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Search for "fusion" in Full Text gives 118 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments
- Aissam Okba,
- Pablo Simón Marqués,
- Kyohei Matsuo,
- Naoki Aratani,
- Hiroko Yamada,
- Gwénaël Rapenne and
- Claire Kammerer
Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30
- -resolution STM and AFM images, revealing the linear fusion of benzene rings with a zigzag edge (Figure 3), and their electronic properties were investigated at the single-molecule scale, with a particular attention devoted to the evolution of the HOMO–LUMO gap along the incremental series of acenes
Graphical Abstract
Scheme 1: “Precursor approach” for the synthesis of π-conjugated polycyclic compounds, with the thermally- or...
Scheme 2: Valence isomerization of chalcogen heteropines and subsequent cheletropic extrusion in the case of ...
Scheme 3: Early example of phenanthrene synthesis via a chemically-induced S-extrusion (and concomitant decar...
Scheme 4: Top: Conversion of dinaphthothiepine bisimides 3a,b and their sulfoxide analogues 4a,b into PBIs 6a,...
Figure 1: Top view (a) and side view (b) of the X-ray crystal structure of thiepine 3b showing its bent confo...
Scheme 5: Modular synthetic route towards dinaphthothiepines 3a–f and the corresponding S-oxides 4a–d, incorp...
Scheme 6: Top: Conversion of dithienobenzothiepine monomeric units into dithienonaphthalenes, upon S-extrusio...
Scheme 7: Synthesis of S-doped extended triphenylene derivative 22 from 3-bromothiophene (17) with the therma...
Scheme 8: Top: Synthesis of thermally-stable O-doped HBC 26a. Bottom: Synthesis of S- and Se-based soluble pr...
Scheme 9: Synthesis of dinaphthooxepine bisimide 33 and conversion into PBI 6f by O-extrusion triggered by el...
Figure 2: Cyclic voltammogram of dinaphthooxepine 33, evidencing the irreversibility of the reduction process...
Scheme 10: Top: Early example of 6-membered ring contraction with concomitant S-extrusion leading to dinaphtho...
Scheme 11: Examples of S-extrusion from annelated 1,2-dithiins under photoactivation (top) or thermal activati...
Scheme 12: Synthesis of dibenzo[1,4]dithiapentalene upon photoextrusion of SO2 [78].
Scheme 13: Extrusion of SO in naphthotrithiin-2-oxides for the synthesis of 2,5-dihydrothiophene 1-oxides [79].
Scheme 14: SO-extrusion as a key step in the synthesis of fullerenes (C60 and C70) encapsulating H2 molecules [80,82]....
Scheme 15: Synthesis of diepoxytetracene precursor 56 and its on-surface conversion into tetracene upon O-extr...
Scheme 16: Soluble precursors of hexacene, decacene and dodecacene incorporating 1,4-epoxides in their hydroca...
Scheme 17: Synthesis of tetraepoxide 59 as soluble precursor of decacene [85].
Figure 3: Constant-height STM measurement of decacene on Au(111) using a CO-functionalized tip (sample voltag...
Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes
- Michio Yamada
Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13
- solution as well as contradictory propensity to form luminescent nanostructure suspensions in hexane (Figure 5) [137]. It was posited that 65 features hollow vesicles, with vesicle fusion releasing curvature energy, leading to a thermodynamically more stable tubular structure. Such aggregation-induced
Graphical Abstract
Scheme 1: Pathway of the [2 + 2] CA–RE reaction of an electron-rich alkyne with TCNE or TCNQ. EDG = electron-...
Scheme 2: Reaction pathway for DMA-appended acetylene and TCNEO.
Scheme 3: Pathway of the [2 + 2] CA–RE reaction between 1 and DCFs.
Scheme 4: Sequential double [2 + 2] CA–RE reactions between 1 and TCNE.
Scheme 5: Divergent chemical transformation pathways of TCBD 6.
Scheme 6: Synthesis of 12.
Scheme 7: [2 + 2] CA–RE reaction of 1 with 14. TCE = 1,1,2,2-tetrachloroethane.
Scheme 8: Autocatalytic model proposed by Nielsen et al.
Scheme 9: Synthesis of anthracene-embedded TCBD compound 19.
Scheme 10: Sequence of the [2 + 2] CA–RE reaction between dibenzo-fused cyclooctyne or cyclooctadiyne and TCNE...
Scheme 11: [2 + 2] CA–RE reaction between the CPP derivatives and TCNE. THF = tetrahydrofuran.
Scheme 12: [2 + 2] CA–RE reaction between ethynylfullerenes 31 and TCNE and subsequent thermal rearrangement.
Scheme 13: Pathway of the [2 + 2] CA–RE reaction between TCNE and 34, followed by additional skeletal transfor...
Scheme 14: Synthesis scheme for heterocycle 38 from the reaction between TCNE and 1 in water and a surfactant.
Scheme 15: Synthesis scheme of the CDA product 41.
Scheme 16: Synthesis of rotaxanes 44 and 46 via the [2 + 2] CA–RE reaction.
Scheme 17: Synthesis of a CuI bisphenanthroline-based rotaxane 50.
Figure 1: Structures of the chiral push–pull chromophores 51–56.
Figure 2: Structures of the axially chiral TCBD 57 and DCNQ 58 bearing a C60 core.
Figure 3: Structures of the axially chiral SubPc–TCBD–aniline conjugates 59 and 60 and the subporphyrin–TCBD–...
Figure 4: Structures of 63 and the TCBD 64.
Figure 5: Structures of the fluorophore-containing TCBDs 65–67.
Figure 6: Structures of the fluorophore-containing TCBDs 68–72.
Figure 7: Structures of the urea-containing TCBDs 73–75.
Figure 8: Structures of the fullerene–TCBD and DCNQ conjugates 76–79 and their reference compounds 80–83.
Figure 9: Structures of the ZnPc–TCBD–aniline conjugates 84 and 85.
Figure 10: Structures of the ZnP–PCBD and TCBD conjugates 86–88.
Figure 11: Structures of the porphyrin-based donor–acceptor conjugates (89–104).
Figure 12: Structures of the porphyrin–PTZ or DMA conjugates 105–112.
Figure 13: Structures of the BODIPY–Acceptor–TPA or PTZ conjugates 113–116.
Figure 14: Structures of the corrole–TCBD conjugates 117 and 118.
Figure 15: Structure of the dendritic TCBD 119.
Figure 16: Structures of the TCBDs 120–126.
Figure 17: Structures of the precursor 127 and TCBDs 128–130.
Figure 18: Structures of 131–134 utilized for BHJ OSCs.
Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway
- Seiji Kawai,
- Akito Yamada,
- Yohei Katsuyama and
- Yasuo Ohnishi
Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1
- and HindIII sites of pHKO4 using In-Fusion (TaKaRa Bio Inc.) [20]. pTYM3a-cmaG was constructed by cloning cmaG (which was amplified by PCR using K. albida genomic DNA as the template) into the NdeI and XbaI sites of pTYM3a using In-Fusion (TaKaRa Bio Inc.). The primers used for plasmid construction
- NdeI and XhoI sites of pColdI using In-Fusion (TaKaRa Bio Inc.). The primers used for plasmid construction are listed in Table S4 of Supporting Information File 1. Each protein expression plasmid was introduced into E. coli BL21(DE3). To obtain holo-CmaA3, pACYC-sfp [21] was co-introduced with pColdI
Graphical Abstract
Figure 1: Comparison of ava and cma clusters and the biosynthetic pathway of p-coumaric acid. A) Schematic re...
Figure 2: Heterologous expression of the cma cluster in S. albus. A) Schematic representation of the gene set...
Figure 3: In vitro analysis of Cma proteins. A) In vitro analysis of CmaA1 and CmaA3. Extracted ion chromatog...
Tying a knot between crown ethers and porphyrins
- Maksym Matviyishyn and
- Bartosz Szyszko
Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120
- revealed a distorted ruffled molecule with a macrocycle incorporating a pyrroloindole subunit formed through the fusion between the para-phenylene ring and the pyrrolic nitrogen. 42 demonstrated fluorophore behaviour with relatively large fluorescence quantum yields of 10–20% and singlet state lifetimes of
Graphical Abstract
Figure 1: Porphyrin and crown ether.
Figure 2: Timeline demonstrating the contributions into the crown ether–porphyrin chemistry.
Figure 3: Tetra-crowned porphyrin 1 and dimer 2 formed upon K+ binding.
Figure 4: meso-Crowned 25-oxasmaragdyrins 3a–c and their boron(III) complexes (3a–c)-BF2.
Scheme 1: CsF ion-pair binding of 4. The molecular structure of 4-CsF is shown on the right [101].
Figure 5: CsF ion pair binding by 5. The molecular structure of 5-CsF is shown on the right [102].
Scheme 2: Ion-pair binding by 6. The molecular structure of (6-CsCl)2 is shown on the right [103].
Scheme 3: Hydrated fluoride binding by 7 [104].
Figure 6: β-Crowned porphyrin 8.
Figure 7: Crown ether-capped porphyrins 9.
Figure 8: The capped porphyrin 10 and complex [10-PQ](PF6)2.
Figure 9: The double-capped porphyrin 11.
Figure 10: Selected examples of iminoporphyrinoids [58,122].
Scheme 4: The synthesis of 13.
Scheme 5: Tripyrrane-based crown ether-embedding porphyrinoid 15.
Figure 11: Macrocycles 16–19 and their coordination compounds.
Scheme 6: The flexibility of 16-Co [66].
Figure 12: Hexagonal wheel composed of six 16-Co(III) monomers [66].
Scheme 7: The synthesis of 16-V [67].
Figure 13: The molecular structure of dimers [16-Mn]2 [67].
Scheme 8: Synthesis of crownphyrins 28–33. Compounds 23a/b and 29a/b were obtained from 4,7,10-trioxa-1,13-tr...
Figure 14: The molecular structures of 22a, 34a·(HCl)2, and 29b [69].
Figure 15: Molecular structures of 22a-Pb and (29b)2-Zn [69].
Scheme 9: Reactivity of 29a/b.
Scheme 10: Synthesis of 36 and 37 [131].
Scheme 11: Synthesis of 40–45.
Figure 16: Potential applications of porphyrin-crown ether hybrids.
Synthesis of ether lipids: natural compounds and analogues
- Marco Antônio G. B. Gomes,
- Alicia Bauduin,
- Chloé Le Roux,
- Romain Fouinneteau,
- Wilfried Berthe,
- Mathieu Berchel,
- Hélène Couthon and
- Paul-Alain Jaffrès
Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96
- mesenchymal transition of breast epithelium cell lines [33], the fusion of membranes with extracellular or intracellular vesicles [34] including neurotransmission vesicles [35]. ELs could also be used as a probe to evaluate climate change [36]. All the articles and reviews reporting the description of natural
Graphical Abstract
Figure 1: Chemical structure of some natural ether lipids (ELs).
Figure 2: Synthesis of lyso-PAF and PAF from 1-O-alkylglycerol [64].
Figure 3: Synthesis of lyso-PAF from 1,3-benzylideneglycerol 3.1 [69].
Figure 4: A) Synthesis of the two enantiomers of octadecylglycerol (4.6 and 4.10) from ᴅ-mannitol (4.1); B) s...
Figure 5: Four-step synthesis of PAF 5.6 from (S)-glycidol [73].
Figure 6: Synthesis of 1-O-alkylglycerol A) from solketal, B) from ᴅ- or ʟ-tartaric acid and the intermediate ...
Figure 7: Synthesis of EL building blocks starting from substituted glycidol 7.1a–c [82].
Figure 8: Synthesis of PAF 8.5 by using phosphoramidite 8.2 [86].
Figure 9: Synthesis of oleyl-PAF 9.7 from ʟ-serine [88].
Figure 10: Synthesis of racemic analogues of lyso-PAF 10.8 and PAF 10.9 featuring a phenyl group between the g...
Figure 11: Synthesis of racemic deoxy-lyso-PAF 11.7 and deoxy-PAF 11.8 [91].
Figure 12: Synthesis of racemic thio-PAF 12.8 [93].
Figure 13: Racemic synthesis of 13.6 to illustrate the modification of the glycerol backbone by adding a methy...
Figure 14: Racemic synthesis of 14.5 as an illustration of the introduction of methyl substituents on the glyc...
Figure 15: Synthesis of functionalized sn-2-acyl chains of PC-EL; A) Steglich esterification or acylation reac...
Figure 16: Synthesis of racemic mc-PAF (16.3), a carbamate analogue of PAF [102].
Figure 17: A) Synthesis of (R)-17.2 and (S)-17.6 starting from (S)-solketal (17.1); B) synthesis of N3-PAF (17...
Figure 18: Modification of the phosphocholine polar head to produce PAF analogues [81].
Figure 19: Racemic PAF analogues 19.3 and 19.5 characterized by the absence of the phosphate group [107].
Figure 20: Synthesis of PIP3-PAF (20.7) [108].
Figure 21: Large-scale synthesis of C18-edelfosine (21.8) [116].
Figure 22: Synthesis of C16-edelfosine (22.10) starting from isopropylidene-ʟ-glyceric acid methyl ester (22.1...
Figure 23: Phosphocholine moiety installation by the use of chlorophosphite 23.2 as key reagent [119].
Figure 24: Synthesis of rac-1-alkyl-2-O-methylglycerol (AMG) [120].
Figure 25: Synthesis of stereocontrolled 1-alkyl-2-O-methyl glycerol 25.9 (AMG) from dimethyl ᴅ-tartrate [81].
Figure 26: A) Racemic synthesis of thioether 26.4 [129,130], B) structure of sulfone analogue 26.5 [129].
Figure 27: Stereocontrolled synthesis of C18-edelfosine thioether analogue 27.8 [118].
Figure 28: Synthesis of thioether 28.4 that include a thiophosphate function [134].
Figure 29: Synthesis of ammonium thioether 29.4 and 29.6 [135].
Figure 30: Synthesis of the N-methylamino analogue of edelfosine 30.6 (BN52211) [138].
Figure 31: Synthesis of 1-desoxy analogues of edelfosine; A) with a saturated alkyl chain; B) synthesis of the...
Figure 32: Stereocontrolled synthesis of edelfosine analogue (S)-32.8 featuring a C18:1 lipid chain [142].
Figure 33: Synthesis of edelfosine analogues with modulation of the lipid chain; A) illustration with the synt...
Figure 34: Synthesis of phospholipid featuring a carbamate function to link the lipid chain to the glycerol un...
Figure 35: Synthesis of sesquiterpene conjugates of phospho glycero ether lipids [148].
Figure 36: Racemic synthesis of methyl-substituted glycerol analogues 36.7 and 36.10: A) synthesis of diether ...
Figure 37: Racemic synthesis of ilmofosine (37.6) [155,156].
Figure 38: A) Stereoselective synthesis of 38.5 via a stereoselective hydroboration reaction; B) synthesis of ...
Figure 39: Racemic synthesis of SRI62-834 (39.6) featuring a spiro-tetrahydrofurane heterocycle in position 2 ...
Figure 40: Racemic synthesis of edelfosine analogue 40.5 featuring an imidazole moiety in sn-2 position [160].
Figure 41: Racemic synthesis of fluorine-functionalized EL: A) Synthesis of 41.6 and B) synthesis of 41.8 [161-163].
Figure 42: A) Synthesis of the β-keto-ester 42.6 that also features a decyl linker between the phosphate and t...
Figure 43: Synthesis of phosphonate-based ether lipids; A) edelfosine phosphonate analogue 43.7 and B) thioeth...
Figure 44: Enantioselective synthesis of phosphonates 44.3 and 44.4 [171].
Figure 45: Racemic synthesis of phosphinate-based ether lipid 45.10 [172].
Figure 46: Racemic synthesis of edelfosine arsonium analogue 46.5 [173].
Figure 47: Synthesis of edelfosine dimethylammonium analogue 47.2 [118].
Figure 48: Synthesis of rac-C18-edelfosine methylammonium analogue 48.4 [176].
Figure 49: A) Synthesis of edelfosine N-methylpyrrolidinium analogue 49.2 or N-methylmorpholinium analogue 49.3...
Figure 50: A) Synthesis of edelfosine’s analogue 50.4 with a PE polar group; B) illustration of a pyridinium d...
Figure 51: A) Synthesis of 51.4 featuring a thiazolium cationic moiety; B) synthesis of thiazolium-based EL 51...
Figure 52: Synthesis of cationic ether lipids 52.3, 52.4 and 52.6 [135,183].
Figure 53: Synthesis of cationic carbamate ether lipid 53.5 [184].
Figure 54: Synthesis of cationic sulfonamide 54.5 [185].
Figure 55: Chemical structure of ONO-6240 (55.1) and SRI-63-119 (55.2).
Figure 56: Synthesis of non-ionic ether lipids 56.2–56.9 [188].
Figure 57: Synthesis of ether lipid conjugated to foscarnet 57.6 [189].
Figure 58: A) Synthesis of ether lipid conjugated to arabinofuranosylcytosine; B) synthesis of AZT conjugated ...
Figure 59: Synthesis of quercetin conjugate to edelfosine [191].
Figure 60: Synthesis of 60.8 (Glc-PAF) [194].
Figure 61: A) Synthesis of amino ether lipid 61.7 functionalized with a rhamnose unit and its amide analogue 6...
Figure 62: A) Synthesis of glucose ether lipid 62.4; B) structure of ether lipid 62.5 possessing a maltose uni...
Figure 63: A) Synthesis of glucuronic methyl ester 63.8; B) structure of cellobiose 63.9 and maltose 63.10 ana...
Figure 64: A) Synthesis of maltosyl glycerolipid 64.7; B) structure of lactose analogue 64.8 prepared followin...
Figure 65: A) Asymmetric synthesis of the aglycone moiety starting from allyl 4-methoxyphenyl ether; B) glycos...
Figure 66: A) Synthesis of ohmline possessing a lactose moiety. B) Structure of other glyco glycero lipids pre...
Figure 67: A) Synthesis of lactose-glycerol ether lipid 67.5; B) analogues possessing a maltose (67.6) or meli...
Figure 68: Synthesis of digalactosyl EL 68.6, A) by using trityl, benzyl and acetyl protecting groups, B) by u...
Figure 69: A) Synthesis of α-ohmline; B) structure of disaccharide ether lipids prepared by using similar meth...
Figure 70: Synthesis of lactose ether lipid 70.3 and its analogue 70.6 featuring a carbamate function as linke...
Figure 71: Synthesis of rhamnopyranoside diether 71.4 [196].
Figure 72: Synthesis of 1-O-hexadecyl-2-O-methyl-3-S-(α-ᴅ-1'-thioglucopyranosyl)-sn-glycerol (72.5) [225].
Figure 73: A) Preparation of lipid intermediate 73.4; B) synthesis of 2-desoxy-C-glycoside 73.10 [226].
Figure 74: Synthesis of galactose-pyridinium salt 74.3 [228].
Figure 75: Synthesis of myo-inositol derivative Ino-C2-PAF (75.10) [230].
Figure 76: A) Synthesis of myo-inositol phosphate building block 76.7; B) synthesis of myo-inositolphosphate d...
Figure 77: A) Synthesis of phosphatidyl-3-desoxy-inositol 77.4; B) synthesis of phosphono-3-desoxyinositol 77.9...
Figure 78: A) Structure of diether phosphatidyl-myo-inositol-3,4-diphosphate 78.1; B) synthesis of phosphatidy...
Figure 79: A) Synthesis of diether-phosphatidyl derivative 79.4 featuring a hydroxymethyl group in place of a ...
Figure 80: Synthesis of Glc-amine-PAF [78].
Figure 81: Synthesis of glucosamine ether lipid 81.4 and its analogues functionalized in position 3 of the ami...
Figure 82: Synthesis of fully deprotected aminoglucoside ether lipid 82.5 [246].
Figure 83: Synthesis of C-aminoglycoside 83.12 using Ramberg–Bäcklund rearrangement as a key step [250].
Figure 84: A) List of the most important glyco lipids and amino glyco lipids included in the study of Arthur a...
Figure 85: Synthesis of mannosamine ether lipid 85.6 [254].
Figure 86: A) Synthesis of glucosamine ether lipids with a non-natural ʟ-glucosamine moiety; B) synthesis of e...
Figure 87: A) Structure of the most efficient anticancer agents 87.1–87.4 featuring a diamino glyco ether lipi...
Figure 88: A) Synthesis of diamino glyco ether lipid 87.4; B) synthesis of bis-glycosylated ether lipid 88.10 [256]....
Figure 89: Synthesis of triamino ether lipid 89.4 [260].
Figure 90: Synthesis of chlorambucil conjugate 90.7 [261].
Figure 91: Three main methods for the preparation of glycerol ether lipid 91.3; A) from solketal and via a tri...
Figure 92: Four different methods for the installation of the phosphocholine polar head group; A) method using...
Figure 93: Illustration of two methods for the installation of saccharides or aminosaccharides; A) O-glycosyla...
Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins
- Chandra Sekhar Tekuri,
- Pargat Singh and
- Mahendra Nath
Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89
- the loss in D4h symmetry after the fusion of a large benzo[f]chromeno[2,3-h]quinoxaline moiety across the porphyrinic β-positions [43], and two Q-bands at ≈562 and 603 nm (Figure 2). Further, the electronic absorpion spectra of free-base benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 9–13 exhibited
- ; Zn-TMPP, Soret band at 425 nm) due to the extended π-conjugation after the fusion of the benzo[f]chromeno[2,3-h]quinoxaline moiety at the β-pyrrolic positions of the porphyrin macrocycle. In the fluorescence spectra, free-base benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 9–13 showed emission bands at
Graphical Abstract
Scheme 1: Synthesis of benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 3–16.
Figure 1: Plausible mechanism for the formation of copper(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrins.
Scheme 2: Sequential synthesis of copper(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrin 3.
Figure 2: Electronic absorption spectra of copper(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 3–8 in CHCl...
Figure 3: Electronic absorption spectra of free-base benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 9–13 in CHCl...
Figure 4: Electronic absorption spectra of zinc(II) benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 14–16 in CHCl...
Figure 5: (a) Emission spectra of free-base benzo[f]chromeno[2,3-h]quinoxalinoporphyrins 9–13 and (b) emissio...
Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series
- Cécile Alleman,
- Charlène Gadais,
- Laurent Legentil and
- François-Hugues Porée
Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23
- backbone resulting from the fusion of a five-, six- and eight-membered ring in which the three rings share a common carbon–carbon bond. Its core structure was investigated in 2011 through the ring-closing metathesis of intermediate 83 [45]. However, the isopropenyl group seemed too hindered and the
Graphical Abstract
Figure 1: Examples of terpenes containing a bicyclo[3.6.0]undecane motif.
Figure 2: Commercially available first and second generation Grubbs and Hoveyda–Grubbs catalysts.
Figure 3: Examples of strategies to access the fusicoccan and ophiobolin tricyclic core structure by RCM.
Scheme 1: Synthesis of bicyclic core structure 12 of ophiobolin M (13) and cycloaraneosene (14).
Scheme 2: Synthesis of the core structure 21 of ophiobolins and fusicoccanes.
Scheme 3: Ring-closing metathesis attempts starting from thioester 22.
Scheme 4: Total synthesis of ent-fusicoauritone (28).
Figure 4: General structure of ophiobolins and congeners.
Scheme 5: Total synthesis of (+)-ophiobolin A (8).
Scheme 6: Investigation of RCM for the synthesis of ophiobolin A (8). Path A) RCM with TBDPS-protected alcoho...
Scheme 7: Synthesis of the core structure of cotylenin A aglycon, cotylenol (50).
Scheme 8: Synthesis of tricyclic core structure of fusicoccans.
Scheme 9: Total synthesis of (−)-teubrevin G (59).
Scheme 10: Synthesis of the core skeleton 63 of the basmane family.
Scheme 11: Total synthesis of (±)-schindilactone A (68).
Scheme 12: Total synthesis of dactylol (72).
Scheme 13: Ring-closing metathesis for the total synthesis of (±)-asteriscanolide (2).
Scheme 14: Synthesis of the simplified skeleton of pleuromutilin (1).
Scheme 15: Total synthesis of (−)-nitidasin (93) using a ring-closing metathesis to construct the eight-member...
Scheme 16: Total synthesis of (±)-naupliolide (97).
Scheme 17: Synthesis of the A-B ring structure of fusicoccane (101).
Scheme 18: First attempts of TRCM of dienyne substrates.
Scheme 19: TRCM on optimized substrates towards the synthesis of ophiobolin A (8).
Scheme 20: Tandem ring-closing metathesis for the synthesis of variecolin intermediates 114 and 115.
Scheme 21: Synthesis of poitediol (118) using the allylsilane ring-closing metathesis.
Scheme 22: Access to scaffold 122 by a NHK coupling reaction.
Scheme 23: Key step to construct the [5-8] bicyclooctanone core of aquatolide (4).
Scheme 24: Initial strategy to access aquatolide (4).
Scheme 25: Synthetic plan to cotylenin A (130).
Scheme 26: [5-8] Bicyclic structure of brachialactone (7) constructed by a Mizoroki–Heck reaction.
Scheme 27: Influence of the replacement of the allylic alcohol moiety.
Scheme 28: Formation of variecolin intermediate 140 through a SmI2-mediated Barbier-type reaction.
Scheme 29: SmI2-mediated ketyl addition. Pleuromutilin (1) eight-membered ring closure via C5–C14 bond formati...
Scheme 30: SmI2-mediated dialdehyde cyclization cascade of [5-8-6] pleuromutilin scaffold 149.
Scheme 31: A) Modular synthetic route to mutilin and pleuromutilin family members by Herzon’s group. B) Scaffo...
Scheme 32: Photocatalyzed oxidative ring expansion in pleuromutilin (1) total synthesis.
Scheme 33: Reductive radical cascade cyclization route towards (−)-6-epi-ophiobolin N (168).
Scheme 34: Reductive radical cascade cyclization route towards (+)-6-epi-ophiobolin A (173).
Scheme 35: Radical 8-endo-trig-cyclization of a xanthate precursor.
Figure 5: Structural representations of hypoestin A (177), albolic acid (178), and ceroplastol II (179) beari...
Scheme 36: Synthesis of the common [5-8-5] tricyclic intermediate of hypoestin A (177), albolic acid (178), an...
Scheme 37: Asymmetric synthesis of hypoestin A (177), albolic acid (178), and ceroplastol II (179).
Figure 6: Scope of the Pauson–Khand reaction.
Scheme 38: Nazarov cyclization revealing the fusicoauritone core structure 192.
Scheme 39: Synthesis of fusicoauritone (28) through Nazarov cyclization.
Scheme 40: (+)-Epoxydictymene (5) synthesis through a Nicholas cyclization followed by a Pauson–Khand reaction...
Scheme 41: Synthesis of aquatolide (4) by a Mukaiyama-type aldolisation.
Scheme 42: Tandem Wolff/Cope rearrangement furnishing the A-B bicyclic moiety 204 of variecolin.
Scheme 43: Asymmetric synthesis of the A-B bicyclic core 205 and 206 of variecolin.
Scheme 44: Formation of [5-8]-fused rings by cyclization under thermal activation.
Scheme 45: Construction of the [5-8-6] tricyclic core structure of variecolin (3) by Diels–Alder reaction.
Scheme 46: Synthesis of the [6-4-8-5]-tetracyclic skeleton by palladium-mediated cyclization.
Scheme 47: Access to the [5-8] bicyclic core structure of asteriscanolide (227) through rhodium-catalyzed cycl...
Scheme 48: Total syntheses of asterisca-3(15),6-diene (230) and asteriscanolide (2) with a Rh-catalyzed cycliz...
Scheme 49: Photocyclization of 2-pyridones to access the [5-8-5] backbone of fusicoccanes.
Scheme 50: Total synthesis of (+)-asteriscunolide D (245) and (+)-aquatolide (4) through photocyclization.
Scheme 51: Biocatalysis pathway to construct the [5-8-5] tricyclic scaffold of brassicicenes.
Scheme 52: Influence of the CotB2 mutant over the cyclization’s outcome of GGDP.
1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures
- Bram Ryckaert,
- Ellen Demeyere,
- Frederick Degroote,
- Hilde Janssens and
- Johan M. Winne
Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12
- like 47 and 49 actually resisted all attempts to further undergo a Diels–Alder reaction with normal dienes, even for highly reactive ones like cyclopentadiene. As a conclusion, the additional benzo-ring fusion seems to be an important factor in the swift propellane-forming reactivity of dithiin-type
Graphical Abstract
Scheme 1: 1,3-Dithianes as useful synthetic building blocks: a) general synthetic utility (in Corey–Seebach-t...
Scheme 2: Metalation of other saturated heterocycles is often problematic due to β-elimination [16,17].
Scheme 3: Thianes as synthetic building blocks in the construction of complex molecules [18].
Figure 1: a) 1,4-Dithiane-type building blocks that can serve as C2-synthons and b) examples of complex targe...
Scheme 4: Synthetic availability of 1,4-dithiane-type building blocks.
Scheme 5: Dithiins and dihydrodithiins as pseudoaryl groups [36-39].
Scheme 6: Metalation of other saturated heterocycles is often problematic due to β-elimination [40-42].
Figure 2: Reactive conformations leading to β-fragmentation for lithiated 1,4-dithianes and 1,4-dithiin.
Scheme 7: Mild metalation of 1,4-dithiins affords stable heteroaryl-magnesium and heteroaryl-zinc-like reagen...
Scheme 8: Dithiin-based dienophiles and their use in synthesis [33,49-54].
Scheme 9: Dithiin-based dienes and their use in synthesis [55-57].
Scheme 10: Stereoselective 5,6-dihydro-1,4-dithiin-based synthesis of cis-olefins [42,58].
Scheme 11: Addition to aldehydes and applications in stereoselective synthesis.
Figure 3: Applications in the total synthesis of complex target products with original attachment place of 1,...
Scheme 12: Direct C–H functionalization methods for 1,4-dithianes [82,83].
Scheme 13: Known cycloaddition reactivity modes of allyl cations [84-100].
Scheme 14: Cycloadditions of 1,4-dithiane-fused allyl cations derived from dihydrodithiin-methanol 90 [101-107].
Scheme 15: Dearomative [3 + 2] cycloadditions of unprotected indoles with 1,4-dithiane-fused allyl alcohol 90 [30]....
Scheme 16: Comparison of reactivity of dithiin-fused allyl alcohols and similar non-cyclic sulfur-substituted ...
Scheme 17: Applications of dihydrodithiins in the rapid assembly of polycyclic terpenoid scaffolds [108,109].
Scheme 18: Dihydrodithiin-mediated allyl cation and vinyl carbene cycloadditions via a gold(I)-catalyzed 1,2-s...
Scheme 19: Activation mode of ethynyldithiolanes towards gold-coordinated 1,4-dithiane-fused allyl cation and ...
Scheme 20: Desulfurization problems.
Scheme 21: oxidative decoration strategies for 1,4-dithiane scaffolds.
Synthesis of (−)-halichonic acid and (−)-halichonic acid B
- Keith P. Reber and
- Emma L. Niner
Beilstein J. Org. Chem. 2022, 18, 1629–1635, doi:10.3762/bjoc.18.174
- coupling constant between the two methine hydrogens at the ring fusion (3J = 12.9 Hz). The rigid nature of the trans-fused 6/5 ring system results in distinct conformers for 9 and 10; fortunately, this allowed for the unambiguous assignment of the relative configurations of these diastereomers via NMR
Graphical Abstract
Figure 1: Structures of halichonic acid ((+)-1) and halichonic acid B ((+)-2).
Scheme 1: Synthesis of (−)-7-amino-7,8-dihydrobisabolene (4) and its conversion to cyclization precursor 7.
Scheme 2: Synthesis of the halichonic acids via a key intramolecular aza-Prins cyclization.
Scheme 3: Proposed intermediates for the intramolecular aza-Prins reaction leading to the formation of ethyl ...
Identification of the new prenyltransferase Ubi-297 from marine bacteria and elucidation of its substrate specificity
- Jamshid Amiri Moghaddam,
- Huijuan Guo,
- Karsten Willing,
- Thomas Wichard and
- Christine Beemelmanns
Beilstein J. Org. Chem. 2022, 18, 722–731, doi:10.3762/bjoc.18.72
- Kit (Qiagen) and PCR amplification of ubiA-297 (922 bp) and menA-1335 (952 bp) genes was carried out using S7 Fusion High-Fidelity DNA Polymerase (Biozym) and designated primer sequences (ubiA-297 forward 5’-CAGGATCCAGGATGTCCAATAAACTAATG-3’ reverse 5’-CGAAGCTTGTCTTAGGTAATGGCAAAAAG-3’; menA forward 5
Graphical Abstract
Figure 1: Prenylated aromatic metabolites are involved in cellular processes like cell respiration (coenzyme Q...
Figure 2: Homology clustering of Ptases encoded in marine Flavobacteria and Saccharomonospora species (G1–G4,...
Figure 3: Regional alignment of ubiA-297 of Maribacter sp. MS6 (EU359911.1) and homologous genes in Z. uligin...
Figure 4: A) Amino acid alignment and binding residues of UbiA-297. G2-Ptases are illustrated in the grey box...
Figure 5: Evaluation of substrate specificity of UbiA-297. Accepted substrates are shown in red, while no pro...
Figure 6: A) Reaction scheme of UbiA-297 catalyzing the assumed para-directed farnesylation of 8-HQA; B) calc...
Synthetic strategies toward 1,3-oxathiolane nucleoside analogues
- Umesh P. Aher,
- Dhananjai Srivastava,
- Girij P. Singh and
- Jayashree B. S
Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182
- -(−)-enantiomer 2, exhibits potential antiviral activity against HIV-1 (EC50 = 0.009 µM) in CEM cells. However, the corresponding ᴅ-(+)-enantiomer is less active against HIV-1 (EC50 = 0.84 µM) [15]. The fusion of an appropriate sugar element, carbacycle, or heterocyclic equivalent with an activated base results
Graphical Abstract
Figure 1: Representative modified 1,3-oxathiolane nucleoside analogues.
Figure 2: Mechanism of antiviral action of 1,3-oxathiolane nucleosides, 3TC (1) and FTC (2), as chain termina...
Figure 3: Synthetic strategies for the construction of the 1,3-oxathiolane sugar ring.
Scheme 1: Synthesis of 4 from benzoyloxyacetaldehyde (3a) and 2-mercapto-substituted dimethyl acetal 3na.
Scheme 2: Synthesis of 8 from protected glycolic aldehyde 3b and 2-mercaptoacetic acid (3o).
Scheme 3: Synthesis of 20 from ᴅ-mannose (3c).
Scheme 4: Synthesis of 20 from 1,6-thioanhydro-ᴅ-galactose (3d).
Scheme 5: Synthesis of 8 from 2-(tert-butyldiphenylsilyloxy)methyl-5-oxo-1,2-oxathiolane (3m).
Scheme 6: Synthesis of 20a from ʟ-gulose derivative 3f.
Scheme 7: Synthesis of 31 from (+)-thiolactic acid 3p and 2-benzoyloxyacetaldehyde (3a).
Scheme 8: Synthesis of 35a from 1,4-dithiane-2,5-diol (3q) and glyoxylic acid (3g) hydrate.
Scheme 9: Synthetic routes toward 41 through Pummerer reaction from methyl 2-mercaptoacetate (3j) and bromoac...
Scheme 10: Strategy for the synthesis of 2,5-substituted 1,3-oxathiolane 41a using 4-nitrobenzyl glyoxylate an...
Scheme 11: Synthesis of 44 by a resolution method using Mucor miehei lipase.
Scheme 12: Synthesis of 45 from benzoyloxyacetaldehyde (3a) and 2-mercaptoacetaldehyde bis(2-methoxyethyl) ace...
Scheme 13: Synthesis of 46 from 2-mercaptoacetaldehyde bis(2-methoxyethyl) acetal (3nc) and diethyl 3-phosphon...
Scheme 14: Synthesis of 48 from 1,3-dihydroxyacetone dimer 3l.
Scheme 15: Approach toward 52 from protected alkene 3rb and lactic acid derivative 51 developed by Snead et al....
Scheme 16: Recent approach toward 56a developed by Kashinath et al.
Scheme 17: Synthesis of 56a from ʟ-menthyl glyoxylate (3h) hydrate by DKR.
Scheme 18: Possible mechanism with catalytic TEA for rapid interconversion of isomers.
Scheme 19: Synthesis of 35a by a classical resolution method through norephedrine salt 58 formation.
Scheme 20: Synthesis of 63 via [1,2]-Brook rearrangement from silyl glyoxylate 61 and thiol 3nb.
Scheme 21: Combined use of STS and CAL-B as catalysts to synthesize an enantiopure oxathiolane precursor 65.
Scheme 22: Synthesis of 1 and 1a from glycolaldehyde dimer 64 and 1,4-dithiane-2,5-diol (3q) using STS and CAL...
Scheme 23: Synthesis of 68 by using Klebsiella oxytoca.
Scheme 24: Synthesis of 71 and 72 using Trichosporon taibachii lipase and kinetic resolution.
Scheme 25: Synthesis of 1,3-oxathiolan-5-ones 77 and 78 via dynamic covalent kinetic resolution.
Figure 4: Pathway for glycosidic bond formation.
Scheme 26: First synthesis of (±)-BCH-189 (1c) by Belleau et al.
Scheme 27: Enantioselective synthesis of 3TC (1).
Scheme 28: Synthesis of cis-diastereomer 3TC (1) from oxathiolane propionate 44.
Scheme 29: Synthesis of (±)-BCH-189 (1c) via SnCl4-mediated N-glycosylation of 8.
Scheme 30: Synthesis of (+)-BCH-189 (1a) via TMSOTf-mediated N-glycosylation of 20.
Scheme 31: Synthesis of 3TC (1) from oxathiolane precursor 20a.
Scheme 32: Synthesis of 83 via N-glycosylation of 20 with pyrimidine bases.
Scheme 33: Synthesis of 85 via N-glycosylation of 20 with purine bases.
Scheme 34: Synthesis of 86 and 87 via N-glycosylation using TMSOTf and pyrimidines.
Scheme 35: Synthesis of 90 and 91 via N-glycosylation using TMSOTf and purines.
Scheme 36: Synthesis of 3TC (1) via TMSI-mediated N-glycosylation.
Scheme 37: Stereoselective N-glycosylation for the synthesis of 1 by anchimeric assistance of a chiral auxilia...
Scheme 38: Whitehead and co-workers’ approach for the synthesis of 1 via direct N-glycosylation without an act...
Scheme 39: ZrCl4-mediated stereoselective N-glycosylation.
Scheme 40: Plausible reaction mechanism for stereoselective N-glycosylation using ZrCl4.
Scheme 41: Synthesis of enantiomerically pure oxathiolane nucleosides 1 and 2.
Scheme 42: Synthesis of tetrazole analogues of 1,3-oxathiolane nucleosides 97.
Scheme 43: Synthetic approach toward 99 from 1,3-oxathiolane 45 by Camplo et al.
Scheme 44: Synthesis of 100 from oxathiolane phosphonate analogue 46.
Scheme 45: Synthetic approach toward 102 and the corresponding cyclic thianucleoside monophosphate 102a by Cha...
Scheme 46: Synthesis of emtricitabine (2) from 1,4-dithiane-2,5-diol (3q) and glyoxylic acid (3g).
Scheme 47: Synthesis of 1 and 2, respectively, from 56a–d using iodine-mediated N-glycosylation.
Scheme 48: Plausible mechanism for silane- and I2-mediated N-glycosylation.
Scheme 49: Pyridinium triflate-mediated N-glycosylation of 35a.
Scheme 50: Possible pathway for stereoselective N-glycosylation via in situ chelation with a metal ligand.
Scheme 51: Synthesis of novel 1,3-oxathiolane nucleoside 108 from oxathiolane precursor 8 and 3-benzyloxy-2-me...
Scheme 52: Synthesis of 110 using T-705 as a nucleobase and 1,3-oxathiolane derivative 8 via N-glycosylation.
Scheme 53: Synthesis of 1 using an asymmetric leaving group and N-glycosylation with bromine and mesitylene.
Scheme 54: Cytidine deaminase for enzymatic separation of 1c.
Scheme 55: Enzymatic resolution of the monophosphate derivative 116 for the synthesis of (−)-BCH-189 (1) and (...
Scheme 56: Enantioselective resolution by PLE-mediated hydrolysis to obtain FTC (2).
Scheme 57: (+)-Menthyl chloroformate as a resolving agent to separate a racemic mixture 120.
Scheme 58: Separation of racemic mixture 1c by cocrystal 123 formation with (S)-(−)-BINOL.
Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing
- Luke O. Jones,
- Leah Williams,
- Tasmin Boam,
- Martin Kalmet,
- Chidubem Oguike and
- Fiona L. Hatton
Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171
- difficulty maintaining porous structures when stacking multiple layers, specifically the fusion of layer contact points without scaffold collapse. The vertical pores remain intact, but horizontal pores in hydrogel scaffolds might collapse due to material softness [64]. Shick et al. also pointed out the
Graphical Abstract
Figure 1: Schematic representation of the process of aqueous cryogel formation, using (a) monomers/small mole...
Figure 2: Microarchitecture of gelatin cryogels. (A) Surface and cross-sectional SEM micrographs of highly po...
Figure 3: Principle of 3D-cryogel printing. A) Illustration of 3D-printing of cryogels. B) Illustration of th...
Figure 4: Illustration of the production of the injectable multifunctional composite, comprised of alginate c...
Figure 5: Digital and SEM photographs of PETEGA cryogel at 20 °C (top) and 50 °C (bottom), synthesised via UV...
Figure 6: Cell morphology of T47D breast cancer cells cultured in HA cryogels. (A) Schematic representation o...
Figure 7: Preparation of PDMA/β-CD cryogel via cryogenic treatment and photochemical crosslinking in frozen s...
Figure 8: (A) Healing rate of wounds treated with autoclaved CG11 cryogels and those treated with 70% ethanol...
Figure 9: In vivo haemostatic capacity evaluation of the cryogels. Blood loss (a) and haemostatic time (b) in...
Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura
- Zhiwei Zhang,
- Tao Zhou,
- Taehui Yang,
- Keisuke Fukaya,
- Enjuro Harunari,
- Shun Saito,
- Katsuhisa Yamada,
- Chiaki Imada,
- Daisuke Urabe and
- Yasuhiro Igarashi
Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141
- ). Correlations for H5/H7, H5/H9, and H7/H9 and large scalar couplings (3JHH > 10 Hz) for H5/H6ax, H6ax/H7, and H5/H9 established the trans-ring fusion of the dehydrodecalin moiety. The axial orientation of the methyl group at C8 was evidenced by NOESY correlations H26/H6ax and H26/H10. Correlations of H25/H10
Graphical Abstract
Figure 1: Structures of nomimicins A–D (4 and 1–3).
Figure 2: COSY and key HMBC correlations for 1.
Figure 3: Relative configuration of 1 determined by ROESY analysis.
Figure 4: Experimental ECD spectra of 1, 2, and 4 and calculated ECD spectrum of 4.
Figure 5: Four tautomers 4a–4d of the tetronic acid moiety of 4 and calculated ECD spectra.
Figure 6: COSY and key HMBC correlations for 3.
Figure 7: Relative configuration of 3 determined by NOESY analysis.
Constrained thermoresponsive polymers – new insights into fundamentals and applications
- Patricia Flemming,
- Alexander S. Münch,
- Andreas Fery and
- Petra Uhlmann
Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138
Graphical Abstract
Figure 1: (a) Schematic representation of the phase stability of a binary mixture based on the free enthalpy ...
Figure 2: Illustration of the relationship between the type of miscibility gap and the temperature dependence...
Figure 3: Schematically pictured phase diagram of a binary mixture composed of a dissolved polymer with a LCS...
Figure 4: Schematic illustration of a thermo-induced swelling behavior of a star polymer composed of responsi...
Figure 5: Schematic illustration of self-assembly of block copolymer amphiphiles in a polar medium.
Figure 6: Schematic comparison of the size and conformation between free polymer chains (a), grafted polymer ...
Figure 7: Comparison of the possible phase diagrams of a polymer in solution with partially miscibility and t...
Figure 8: Selection of polymers exhibiting UCST behavior due to hydrogen bonding (blue) divided into homo- (a...
Figure 9: Part A shows the molecular structure of PDMAPS stars synthesized by Li et al. (left) demonstrating ...
Figure 10: Part A contains a schematic demonstration of conformational transitions of dual-thermoresponsive bl...
Figure 11: Part A pictures zwitterionic brushes grafted from silicon substrates obtaining a nonassociated, hyd...
Figure 12: Part A pictures the UCST phase transition of zwitterionic polymers grafted on the surface of mesopo...
Double-headed nucleosides: Synthesis and applications
- Vineet Verma,
- Jyotirmoy Maity,
- Vipin K. Maikhuri,
- Ritika Sharma,
- Himal K. Ganguly and
- Ashok K. Prasad
Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98
Graphical Abstract
Figure 1: Double-headed nucleosides. B1 and B2 = nucleobases or heterocyclic/carbocyclic moieties; L = linker....
Scheme 1: Synthesis of 2′-(pyrimidin-1-yl)methyl- or 2′-(purin-9-yl)methyl-substituted double-headed nucleosi...
Scheme 2: Synthesis of double-headed nucleoside 7 having two cytosine moieties.
Scheme 3: Synthesis of double-headed nucleoside 2′-deoxy-2′-C-(2-(thymine-1-yl)ethyl)-uridine (11).
Scheme 4: Double-headed nucleosides 14 and 15 obtained by click reaction.
Scheme 5: Synthesis of the double-headed nucleoside 19.
Scheme 6: Synthesis of the double-headed nucleosides 24 and 25.
Scheme 7: Synthesis of double-headed nucleosides 28 and 29.
Scheme 8: Synthesis of double-headed nucleoside 33.
Scheme 9: Synthesis of double-headed nucleoside 37.
Scheme 10: Synthesis of the double-headed nucleoside 1-(5′-O-(4,4′-dimethoxytrityl)-2′-C-((4-(pyren-1-yl)-1,2,...
Scheme 11: Synthesis of triazole-containing double-headed ribonucleosides 46a–c and 50a–e.
Scheme 12: Synthesis of double-headed nucleosides 54a–g.
Scheme 13: Synthesis of double-headed nucleosides 59 and 60.
Scheme 14: Synthesis of the double-headed nucleosides 63 and 64.
Scheme 15: Synthesis of double-headed nucleosides 66a–c.
Scheme 16: Synthesis of benzoxazole-containing double-headed nucleosides 69 and 71 from 5′-amino-5′-deoxynucle...
Scheme 17: Synthesis of 4′-C-((N6-benzoyladenin-9-yl)methyl)thymidine (75) and 4′-C-((thymin-1-yl)methyl)thymi...
Scheme 18: Synthesis of double-headed nucleosides 5′-(adenine-9-yl)-5′-deoxythymidine (79) and 5′-(adenine-9-y...
Scheme 19: Synthesis of double-headed nucleosides 85–87 via reversed nucleosides methodology.
Scheme 20: Double-headed nucleosides 91 and 92 derived from ω-terminal-acetylenic sugar derivatives 90a,b.
Scheme 21: Synthesis of double-headed nucleosides 96a–g.
Scheme 22: Synthesis of double-headed nucleosides 100 and 103.
Scheme 23: Double-headed nucleosides 104 and 105 with a triazole motif.
Scheme 24: Synthesis of the double-headed nucleosides 107 and 108.
Scheme 25: Synthesis of double-headed nucleoside 110 with additional nucleobase in 5′-(S)-C-position joined th...
Scheme 26: Synthesis of double-headed nucleosides 111–113 with additional nucleobases in the 5′-(S)-C-position...
Scheme 27: Synthesis of double-headed nucleoside 114 by click reaction.
Scheme 28: Synthesis of double-headed nucleosides 118 with an additional nucleobase at the 5′-(S)-C-position.
Scheme 29: Synthesis of bicyclic double-headed nucleoside 122.
Scheme 30: Synthesis of double-headed nucleosides 125a–c derived from 2′-amino-LNA.
Scheme 31: Double-headed nucleoside 127 obtained by click reaction.
Scheme 32: Synthesis of double-headed nucleoside 130.
Scheme 33: Double-headed nucleosides 132a–d and 134a–d synthesized by Sonogashira cross coupling reaction.
Scheme 34: Synthesis of double-headed nucleosides 137 and 138 via Suzuki coupling.
Scheme 35: Synthesis of double-headed nucleosides 140 and 141 via Sonogashira cross coupling reaction.
Scheme 36: Synthesis of double-headed nucleoside 143.
Scheme 37: Synthesis of the double-headed nucleoside 146.
Scheme 38: Synthesis of 5-C-alkynyl-functionalized double-headed nucleosides 151a–d.
Scheme 39: Synthesis of 5-C-triazolyl-functionalized double-headed nucleosides 154a, b.
Scheme 40: Synthesis of double-headed nucleosides 157a–c.
Scheme 41: Synthesis of double-headed nucleoside 159, phosphoramidite 160 and the corresponding nucleotide mon...
Scheme 42: Synthesis of double-headed nucleoside 163, phosphoramidite 164 and the corresponding nucleotide mon...
Scheme 43: Synthesis of double-headed nucleoside 167, phosphoramidite 168, and the corresponding nucleotide mo...
Scheme 44: Synthesis of double-headed nucleoside 171, phosphoramidite 172, and the corresponding nucleotide mo...
Scheme 45: Synthesis of double-headed nucleoside 175, phosphoramidite 176, and the corresponding nucleotide mo...
Scheme 46: Synthesis of double-headed nucleoside 178.
Scheme 47: Synthesis of the double-headed nucleosides 181 and 183.
Scheme 48: Alternative synthesis of the double-headed nucleoside 183.
Scheme 49: Synthesis of double-headed nucleoside 188 through thermal [2 + 3] sydnone–alkyne cycloaddition reac...
Scheme 50: Synthesis of the double-headed nucleosides 190 and 191.
Scheme 51: Synthesis of 1-((5S)-2,3,4-tri-O-acetyl-5-(2,6-dichloropurin-9-yl)-β-ᴅ-xylopyranosyl)uracil (195).
Scheme 52: Synthesis of hexopyranosyl double-headed pyrimidine homonucleosides 200a–c.
Figure 2: 3′-C-Ethynyl-β-ᴅ-allopyranonucleoside derivatives 201a–f.
Scheme 53: Synthesis of 3′-C-(1,4-disubstituted-1,2,3-triazolyl)-double-headed pyranonucleosides 203–207.
Scheme 54: Synthesis of 3′-C-(1,4-disubstituted-1,2,3-triazolyl)-double-headed pyranonucleosides 208 and 209.
Scheme 55: Synthesis of 3′-C-(1,4-disubstituted-1,2,3-triazolyl)-double-headed pyranonucleoside 210.
Scheme 56: Synthesis of double-headed acyclic nucleosides (2S,3R)-1,4-bis(thymine-1-yl)butane-2,3-diol (213a) ...
Scheme 57: Synthesis of double-headed acyclic nucleosides (2R,3S)-1,4-bis(thymine-1-yl)butane-2,3-diol (213c) ...
Scheme 58: Synthesis of double-headed acetylated 1,3,4-oxadiazino[6,5-b]indolium-substituted C-nucleosides 218b...
Scheme 59: Synthesis of double-headed acyclic nucleoside 222.
Scheme 60: Synthesis of functionalized 1,2-bis(1,2,4-triazol-3-yl)ethane-1,2-diols 223a–f.
Scheme 61: Synthesis of acyclic double-headed 1,2,4-triazino[5,6-b]indole C-nucleosides 226–231.
Scheme 62: Synthesis of double-headed 1,3,4-thiadiazoline, 1,3,4-oxadiazoline, and 1,2,4-triazoline acyclo C-n...
Scheme 63: Synthesis of double-headed acyclo C-nucleosides 240–242.
Scheme 64: Synthesis of double-headed acyclo C-nucleoside 246.
Scheme 65: Synthesis of acyclo double-headed nucleoside 250.
Scheme 66: Synthesis of acyclo double-headed nucleoside 253.
Scheme 67: Synthesis of acyclo double-headed nucleosides 259a–d.
Scheme 68: Synthesis of acyclo double-headed nucleoside 261.
Design, synthesis and photophysical properties of novel star-shaped truxene-based heterocycles utilizing ring-closing metathesis, Clauson–Kaas, Van Leusen and Ullmann-type reactions as key tools
- Shakeel Alvi and
- Rashid Ali
Beilstein J. Org. Chem. 2021, 17, 1374–1384, doi:10.3762/bjoc.17.96
- . 320.41 nm and 291.07 nm in addition to an extra band at 263.22 nm due to the fusion of three benzene rings onto the imidazole moieties. In sharp contrast, more red-shifted absorption bands at 341.64 nm and 326.99 nm along with two shoulders at ca. 306.75 nm, and 279.94 nm were found with truxene having
Graphical Abstract
Scheme 1: Retrosynthetic pathways to the pyrrole-based C3-symmetric truxene derivative 6.
Scheme 2: Synthesis of tripyrrolotruxene 6 via cyclotrimerization and RCM as crucial steps.
Scheme 3: Synthesis of star-shaped molecule 6 utilizing the Clauson–Kaas pyrrole strategy.
Scheme 4: Synthesis of truxene derivative 6 involving Ullmann-type cross-coupling reaction.
Scheme 5: Synthesis of imidazole and benzimidazole containing truxene derivatives 14 and 16.
Scheme 6: Construction of truxene-based di- and trioxazole derivatives 21 and 20.
Scheme 7: Synthesis of benzene-bridged rings containing trioxazolotruxene system 25.
Figure 1: Normalized absorption (left); fluorescence spectra (right) of the synthesized truxene derivatives (...
Synthetic accesses to biguanide compounds
- Oleksandr Grytsai,
- Cyril Ronco and
- Rachid Benhida
Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82
- ], b) the direct fusion of cyanoguanidine with amine hydrochlorides [14], and c) heating a mixture of these components in alcohol (Scheme 1) [15]. Surprisingly, these methods are still largely popular nowadays. Reaction of cyanoguanidine with amines in the presence of copper salts: Cyanoguanidine was
- examples have also been reported for the addition of amines to arylcyanoguanidines (vide infra). Fusion of cyanoguanidine and amine hydrochlorides: The direct fusion of a mixture of cyanoguanidine and amine salts was one of the earliest synthetic methods of biguanides, described for the first time in 1892
- and shorter reaction times were reported by Tonelli et al. who described the preparation of different cycloalkyl- and benzylbiguanides with relatively good yields (69–84%) after only 1 h of fusion at 180–200 °C (Scheme 3B) [18]. Heating of cyanoguanidine and amine hydrochlorides in a solvent: Early in
Graphical Abstract
Figure 1: Tautomeric forms of biguanide.
Figure 2: Illustrations of neutral, monoprotonated, and diprotonated structures biguanide.
Figure 3: The main approaches for the synthesis of biguanides. The core structure is obtained via the additio...
Scheme 1: The three main preparations of biguanides from cyanoguanidine.
Scheme 2: Synthesis of butylbiguanide using CuCl2 [16].
Scheme 3: Synthesis of biguanides by the direct fusion of cyanoguanidine and amine hydrochlorides [17,18].
Scheme 4: Synthesis of ethylbiguanide and phenylbiguanide as reported by Smolka and Friedreich [14].
Scheme 5: Synthesis of arylbiguanides through the reaction of cyanoguanidine with anilines in water [19].
Scheme 6: Synthesis of aryl- and alkylbiguanides by adaptations of Cohn’s procedure [20,21].
Scheme 7: Microwave-assisted synthesis of N1-aryl and -dialkylbiguanides [22,23].
Scheme 8: Synthesis of aryl- and alkylbiguanides by trimethylsilyl activation [24,26].
Scheme 9: Synthesis of phenformin analogs by TMSOTf activation [27].
Scheme 10: Synthesis of N1-(1,2,4-triazolyl)biguanides [28].
Scheme 11: Synthesis of 2-guanidinobenzazoles by addition of ortho-substituted anilines to cyanoguanidine [30,32] and...
Scheme 12: Synthesis of 2,4-diaminoquinazolines by the addition of 2-cyanoaniline to cyanoguanidine and from 3...
Scheme 13: Reactions of anthranilic acid and 2-mercaptobenzoic acid with cyanoguanidine [24,36,37].
Scheme 14: Synthesis of disubstituted biguanides with Cu(II) salts [38].
Scheme 15: Synthesis of an N1,N2,N5-trisubstituted biguanide by fusion of an amine hydrochloride and 2-cyano-1...
Scheme 16: Synthesis of N1,N5-disubstituted biguanides by the addition of anilines to cyanoguanidine derivativ...
Scheme 17: Microwave-assisted additions of piperazine and aniline hydrochloride to substituted cyanoguanidines ...
Scheme 18: Synthesis of N1,N5-alkyl-substituted biguanides by TMSOTf activation [27].
Scheme 19: Additions of oxoamines hydrochlorides to dimethylcyanoguanidine [49].
Scheme 20: Unexpected cyclization of pyridylcyanoguanidines under acidic conditions [50].
Scheme 21: Example of industrial synthesis of chlorhexidine [51].
Scheme 22: Synthesis of symmetrical N1,N5-diarylbiguanides from sodium dicyanamide [52,53].
Scheme 23: Synthesis of symmetrical N1,N5-dialkylbiguanides from sodium dicyanamide [54-56].
Scheme 24: Stepwise synthesis of unsymmetrical N1,N5-trisubstituted biguanides from sodium dicyanamide [57].
Scheme 25: Examples for the synthesis of unsymmetrical biguanides [58].
Scheme 26: Examples for the synthesis of an 1,3-diaminobenzoquinazoline derivative by the SEAr cyclization of ...
Scheme 27: Major isomers formed by the SEAr cyclization of symmetric biguanides derived from 2- and 3-aminophe...
Scheme 28: Lewis acid-catalyzed synthesis of 8H-pyrrolo[3,2-g]quinazoline-2,4-diamine [63].
Scheme 29: Synthesis of [1,2,4]oxadiazoles by the addition of hydroxylamine to dicyanamide [49,64].
Scheme 30: Principle of “bisamidine transfer” and analogy between the reactions with N-amidinopyrazole and N-a...
Scheme 31: Representative syntheses of N-amidino-amidinopyrazole hydrochloride [68,69].
Scheme 32: First examples of biguanide syntheses using N-amidino-amidinopyrazole [66].
Scheme 33: Example of “biguanidylation” of a hydrazide substrate [70].
Scheme 34: Example for the synthesis of biguanides using S-methylguanylisothiouronium iodide as “bisamidine tr...
Scheme 35: Synthesis of N-substituted N1-cyano-S-methylisothiourea precursors.
Scheme 36: Addition routes on N1-cyano-S-methylisothioureas.
Scheme 37: Synthesis of an hydroxybiguanidine from N1-cyano-S-methylisothiourea [77].
Scheme 38: Synthesis of an N1,N2,N3,N4,N5-pentaarylbiguanide from the corresponding triarylguanidine and carbo...
Scheme 39: Reactions of N,N,N’,N’-tetramethylguanidine (TMG) with carbodiimides to synthesize hexasubstituted ...
Scheme 40: Microwave-assisted addition of N,N,N’,N’-tetramethylguanidine to carbodiimides [80].
Scheme 41: Synthesis of N1-aryl heptasubstituted biguanides via a one-pot biguanide formation–copper-catalyzed ...
Scheme 42: Formation of 1,2-dihydro-1,3,5-triazine derivatives by the reaction of guanidine with excess carbod...
Scheme 43: Plausible mechanism for the spontaneous cyclization of triguanides [82].
Scheme 44: a) Formation of mono- and disubstituted (iso)melamine derivatives by the reaction of biguanides and...
Scheme 45: Reactions of 2-aminopyrimidine with carbodiimides to synthesize 2-guanidinopyrimidines as “biguanid...
Scheme 46: Non-catalyzed alternatives for the addition of 2-aminopyrimidine derivatives to carbodiimides. A) h...
Scheme 47: Addition of guanidinomagnesium halides to substituted cyanamides [90].
Scheme 48: Microwave-assisted synthesis of [11C]metformin by the reaction of 11C-labelled dimethylcyanamide an...
Scheme 49: Formation of 4-amino-6-dimethylamino[1,3,5]triazin-2-ol through the reaction of Boc-guanidine and d...
Scheme 50: Formation of 1,3,5-triazine derivatives via the addition of guanidines to substituted cyanamides [92].
Scheme 51: Synthesis of biguanide by the reaction of O-alkylisourea and guanidine [93].
Scheme 52: Aromatic nucleophilic substitution of guanidine on 2-O-ethyl-1,3,5-triazine [95].
Scheme 53: Synthesis of N1,N2-disubstituted biguanides by the reaction of guanidine and thioureas in the prese...
Scheme 54: Cyclization reactions involving condensations of guanidine(-like) structures with thioureas [97,98].
Scheme 55: Condensations of guanidine-like structures with thioureas [99,100].
Scheme 56: Condensations of guanidines with S-methylisothioureas [101,102].
Scheme 57: Addition of 2-amino-1,3-diazaaromatics to S-alkylisothioureas [103,104].
Scheme 58: Addition of guanidines to 2-(methylsulfonyl)pyrimidines [105].
Scheme 59: An example of a cyclodesulfurization reaction to a fused 3,5-diamino-1,2,4-triazole [106].
Scheme 60: Ring-opening reactions of 1,3-diaryl-2,4-bis(arylimino)-1,3-diazetidines [107].
Scheme 61: Formation of 3,5-diamino-1,2,4-triazole derivatives via addition of hydrazines to 1,3-diazetidine-2...
Scheme 62: Formation of a biguanide via the addition of aniline to 1,2,4-thiadiazol-3,5-diamines, ring opening...
Figure 4: Substitution pattern of biguanides accessible by synthetic pathways a–h.
Simulating the enzymes of ganglioside biosynthesis with Glycologue
- Andrew G. McDonald and
- Gavin P. Davey
Beilstein J. Org. Chem. 2021, 17, 739–748, doi:10.3762/bjoc.17.64
- then to subsequent ceramide-linked glycoconjugate acceptors, before transport and eventual incorporation into the plasma membrane via vesicular fusion. Gangliosides, which function as antigenic determinants [4], may play a role in membrane organization [5], cell signaling [6], apoptosis [7], and in
Graphical Abstract
Figure 1: Chemical structure of ganglioside GM1a (a β-ᴅ-galactosyl-(1→3)-N-acetyl-β-ᴅ-galactosaminyl-(1→4)-[α-...
Figure 2: Construction of the Svennerholm name GP1cα from its Glycologue structure identifier. At each step o...
Figure 3: Ganglioside carbohydrates predicted by the model. All structures are linked to ceramide at the base...
Figure 4: Ganglioside biosynthetic reaction network predicted by the Glycologue enzyme simulator. Starting fr...
Figure 5: Predicted effects on the pathways of ganglioside biosynthesis when individual enzyme activities are...
Semiautomated glycoproteomics data analysis workflow for maximized glycopeptide identification and reliable quantification
- Steffen Lippold,
- Arnoud H. de Ru,
- Jan Nouta,
- Peter A. van Veelen,
- Magnus Palmblad,
- Manfred Wuhrer and
- Noortje de Haan
Beilstein J. Org. Chem. 2020, 16, 3038–3051, doi:10.3762/bjoc.16.253
- ) and 20% water/80% acetonitrile + 0.1% formic acid (B) were used. A gradient from 10–40% of the mobile phase B was applied within 20 min. The LC was hyphenated to an Orbitrap Fusion Lumos MS (Thermo Fisher Scientific). For MS1 analysis, scans were acquired in a mass range of m/z 400–3,500 in positive
Graphical Abstract
Figure 1: Integration of automated glycopeptide identification by Byonic and GlycopeptideGraphMS (aided by Op...
Figure 2: Representative IgG and IgA glycopeptide clusters detected by GlycopeptideGraphMS.
Figure 3: Representative GlycopeptideGraphMS output for peptides of interest. Assigned compositions were iden...
Figure 4: Comparison of quantification results obtained by manual integration of EICs in Skyline (black), aut...
Using multiple self-sorting for switching functions in discrete multicomponent systems
- Amit Ghosh and
- Michael Schmittel
Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233
- . The successive addition of the supramolecular architecture 55 and (57 + 58), a mixture of triangle and square, first induced a fusion into the three-component quadrilateral 56 (SelfSORT-II) and then to the five-component scalene triangle 59 (SelfSORT-III). The cycle was closed upon the addition of the
Graphical Abstract
Figure 1: Some selected self-sorting outcomes and their qualitative and quantitative assessment.
Figure 2: Illustration of an integrative vs a non-integrative self-sorting.
Figure 3: The pH-driven four-component 2-fold completive self-sorting based on host–guest chemistry.
Figure 4: (a) The monomers 5 and 6 and their H-bonding array. (b) The hydrogen-bonded octameric and tetrameri...
Figure 5: (a) Two new Zn4L6-type cages. (b) The encapsulation of C70 induced distinct reconstitutions within ...
Figure 6: The formation of octahedral cages (a) [Co6(10')4]12+ and (b) [Co6(11')4]12+. (c) The 2-fold complet...
Figure 7: Exchange of Ag+ for Au+ ions in poly-NHC ligand-based organometallic assemblies.
Figure 8: The reversible interconversion between the three-component rectangle [Cu4(16)2(17)2]4+ and the four...
Figure 9: a) Chemical structure of the monomer 20 with its quadruple hydrogen-bonding array and a metal-affin...
Figure 10: Communication between the nanoswitch 21 and the supramolecular assemblies [Cu4(22)2(24)2]4+ or [Cu6(...
Figure 11: (a) The chemical structures and cartoon representations of the switch 25, the decks 26 and 27, and ...
Figure 12: Double self-sorting leads to a catalytic machinery in SelfSORT-II, in which the 46 kHz-nanorotor ac...
Figure 13: ON/OFF control of a networked catalytic catch–release system.
Figure 14: A multicomponent information system for the reversible reconfiguration of switchable dual catalysis....
Figure 15: a) The chemically fueled cascaded ion translocation, monitored by distinct emission colors. b) Work...
Figure 16: Cyclic metallosupramolecular transformations.
Figure 17: Fully reversible multiple-state rearrangement of metallosupramolecular architectures depending upon...
Figure 18: The selective encapsulation and sequential release of guests in a self-sorted mixture of three tetr...
Figure 19: Two catalytic reactions are alternately controlled by a toggle nanoswitch.
Figure 20: A biped walking along a tetrahedral track and unfolding its catalytic action. Adapted with permissi...
Figure 21: A three state supramolecular AND logic gate.
Figure 22: Four-component nanorotor and its catalytic activity. Adapted with permission from (Biswas, P. K.; S...
Tools for generating and analyzing glycan microarray data
- Akul Y. Mehta,
- Jamie Heimburg-Molinaro and
- Richard D. Cummings
Beilstein J. Org. Chem. 2020, 16, 2260–2271, doi:10.3762/bjoc.16.187
- to extraneous factors such as poor printing due to a flaw in the surface, spot overlap/fusion with adjacent spot or presence of dust particles are flagged with a “bad” (or some numeric value) flag, so as to be disregarded in the data processing. The software then provides a results file as an output
Graphical Abstract
Figure 1: Overview of a typical glycan microarray workflow, beginning with the obtention of glycans to analys...
Figure 2: A decision tree to determine which type of surface to use depending on glycoconjugate and linker ty...
Figure 3: Screenshot of microarray databases: (A) Screenshot of an example of CFG glycan array data; (B) scre...
Figure 4: A demonstration of glycan array data visualization with GLAD. The dataset used is from Byrd-Leotis ...
Automated high-content imaging for cellular uptake, from the Schmuck cation to the latest cyclic oligochalcogenides
- Rémi Martinent,
- Javier López-Andarias,
- Dimitri Moreau,
- Yangyang Cheng,
- Naomi Sakai and
- Stefan Matile
Beilstein J. Org. Chem. 2020, 16, 2007–2016, doi:10.3762/bjoc.16.167
- react with carboxylate in the active site to produce an ester, and thus covalently attach the transporter to the fusion protein (Figure 6b). The subsequently added reporter 26 passively diffuses into the cells and labels all free HaloTags. The fluorescence signal from the HaloTag reporter 26 is then
- , using multiwell plates and registering data on the fluorescence intensity and fluorescence localization in thousands of cells per condition, at HT [56][57][58][59]. To properly assess its potential, automated HC imaging was optimized first. The fluorescence of the Hoechst dye and the GFP of the fusion
- generally decreases with the size [18], this similarity is particularly impressive, considering that the COC carrying a 52 kDa protein is compared to a small undecapeptide. The compatibility of the assay with other fusion proteins and more adverse conditions, such as transient transfection, has never been
Graphical Abstract
Figure 1: Schematic representation of binding models between organic cations (simple ammonium, guanidinium, S...
Figure 2: From Schmuck cations to cell-penetrating dipeptides, with schematic representation of the binding m...
Figure 3: Peptide tweezers and cyclic peptides with Schmuck cations for gene transfection.
Figure 4: Evolution from CPPs to CPDs and COCs.
Figure 5: Structure of a) the trifunctional transporter 23 and c) the HaloTag reporter 26. b) Schematic mecha...
Figure 6: CAPA assay for the complex 25, composed of three transporters 23 bound to one streptavidin 24 (with...
Figure 7: Examples from the automated HC imaging of stable HGM cells with HaloTag–GFP on mitochondria, labele...
Figure 8: Evaluation of the automated HC imaging of stable HGM cells with HaloTag–GFP on mitochondria, labele...
Figure 9: a) Automated HC imaging of the cellular uptake of 25, covering the concentration dependence for the...
Figure 10: Examples of automated HC imaging of transiently transfected HeLa cells with HaloTag–GFP on Golgi, l...
Figure 11: Evaluation of the automated HC imaging of the transiently transfected HeLa cells with HaloTag–GFP o...
Heterogeneous photocatalysis in flow chemical reactors
- Christopher G. Thomson,
- Ai-Lan Lee and
- Filipe Vilela
Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125
- that permits using long-wavelength irradiation to deeply penetrate through a reaction medium and material surface and activate the bulk of the material. Congreve, Rovis, Campos, and co-workers utilised triplet fusion upconversion to drive a series of homogeneous photoredox transformations with >700 nm
Graphical Abstract
Figure 1: A) Bar chart of the publications per year for the topics “Photocatalysis” (49,662 instances) and “P...
Figure 2: A) Professor Giacomo Ciamician and Dr. Paolo Silber on their roof laboratory at the University of B...
Scheme 1: PRC trifluoromethylation of N-methylpyrrole (1) using hazardous gaseous CF3I safely in a flow react...
Figure 3: A) Unit cells of the three most common crystal structures of TiO2: rutile, brookite, and anatase. R...
Figure 4: Illustration of the key semiconductor photocatalysis events: 1) A photon with a frequency exceeding...
Figure 5: Photocatalytic splitting of water by oxygen vacancies on a TiO2(110) surface. Reprinted with permis...
Figure 6: Proposed adsorption modes of A) benzene, B) chlorobenzene, C) toluene, D) phenol, E) anisole, and F...
Figure 7: Structures of the sulfonate-containing organic dyes RB5 (3) and MX-5B (4) and the adsorption isothe...
Figure 8: Idealised triclinic unit cell of a g-C3N4 type polymer, displaying possible hopping transport scena...
Figure 9: Idealised structure of a perfect g-C3N4 sheet. The central unit highlighted in red represents one t...
Figure 10: Timeline of the key processes of charge transport following the photoexcitation of g-C3N4, leading ...
Scheme 2: Photocatalytic bifunctionalisation of heteroarenes using mpg-C3N4, with the selected examples 5 and ...
Figure 11: A) Structure of four linear conjugated polymer photocatalysts for hydrogen evolution, displaying th...
Figure 12: Graphical representation of the common methods used to immobilise molecular photocatalysts (PC) ont...
Figure 13: Wireless light emitter-supported TiO2 (TiO2@WLE) HPCat spheres powered by resonant inductive coupli...
Figure 14: Graphical representation of zinc–perylene diimide (Zn-PDI) supramolecular assembly photocatalysis v...
Scheme 3: Upconversion of NIR photons to the UV frequency by NaYF4:Yb,Tm nanocrystals sequentially coated wit...
Figure 15: Types of reactors employed in heterogeneous photocatalysis in flow. A) Fixed bed reactors and the s...
Figure 16: Electrochemical potential of common semiconductor, transition metal, and organic dye-based photocat...
Scheme 4: Possible mechanisms of an immobilised molecular photoredox catalyst by oxidative or reductive quenc...
Scheme 5: Scheme of the CMB-C3N4 photocatalytic decarboxylative fluorination of aryloxyacetic acids, with the...
Scheme 6: Scheme of the g-C3N4 photocatalytic desilylative coupling reaction in flow and proposed mechanism [208].
Scheme 7: Proposed mechanism of the radical cyclisation of unsaturated alkyl 2-bromo-1,3-dicarbonyl compounds...
Scheme 8: N-alkylation of benzylamine and schematic of the TiO2-coated microfluidic device [213].
Scheme 9: Proposed mechanism of the Pt@TiO2 photocatalytic deaminitive cyclisation of ʟ-lysine (23) to ʟ-pipe...
Scheme 10: A) Proposed mechanism for the photocatalytic oxidation of phenylboronic acid (24). B) Photos and SE...
Scheme 11: Proposed mechanism for the DA-CMP3 photocatalytic aza-Henry reaction performed in a continuous flow...
Scheme 12: Proposed mechanism for the formation of the cyclic product 32 by TiO2-NC HPCats in a slurry flow re...
Scheme 13: Reaction scheme for the photocatalytic synthesis of homo and hetero disulfides in flow and scope of...
Scheme 14: Reaction scheme for the MoOx/TiO2 HPCat oxidation of cyclohexane (34) to benzene. The graph shows t...
Scheme 15: Proposed mechanism of the TiO2 HPC heteroarene C–H functionalisation via aryl radicals generated fr...
Scheme 16: Scheme of the oxidative coupling of benzylamines with the HOTT-HATN HPCat and selected examples of ...
Scheme 17: Photocatalysis oxidation of benzyl alcohol (40) to benzaldehyde (41) in a microflow reactor coated ...
Figure 17: Mechanisms of Dexter and Forster energy transfer.
Scheme 18: Continuous flow process for the isomerisation of alkenes with an ionic liquid-immobilised photocata...
Scheme 19: Singlet oxygen synthetic step in the total synthesis of canataxpropellane [265].
Scheme 20: Scheme and proposed mechanism of the singlet oxygen photosensitisation by CMP_X HPCats, with the st...
Scheme 21: Structures of CMP HPCat materials applied by Vilela and co-workers for the singlet oxygen photosens...
Scheme 22: Polyvinylchloride resin-supported TDCPP photosensitisers applied for singlet oxygen photosensitisat...
Scheme 23: Structure of the ionically immobilised TPP photosensitiser on amberlyst-15 ion exchange resins (TPP...
Scheme 24: Photosensitised singlet oxygen oxidation of citronellol (46) in scCO2, with automatic phase separat...
Scheme 25: Schematic of PS-Est-BDP-Cl2 being applied for singlet oxygen photosensitisation in flow. A) Pseudo-...
Scheme 26: Reaction scheme of the singlet oxygen oxidation of furoic acid (54) using a 3D-printed microfluidic...
Figure 18: A) Photocatalytic bactericidal mechanism by ROS oxidative cleavage of membrane lipids (R = H, amino...
Figure 19: A) Suggested mechanisms for the aqueous pollutant degradation by TiO2 in a slurry flow reactor [284-287]. B)...
Figure 20: Schematic of the flow system used for the degradation of aqueous oxytetracycline (56) solutions [215]. M...
Scheme 27: Degradation of a salicylic acid (57) solution by a coupled solar photoelectro-Fenton (SPEF) process...
Figure 21: A) Schematic flow diagram using the TiO2-coated NETmix microfluidic device for an efficient mass tr...
Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties
- Liliia Moshniaha,
- Marika Żyła-Karwowska,
- Joanna Cybińska,
- Piotr J. Chmielewski,
- Ludovic Favereau and
- Marcin Stępień
Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81
- ], with FeCl3 being particularly notable for its versatility, ease of use, and low price [5]. Nevertheless, the synthetic utility of oxidative couplings is often limited by several factors [6]. Consequently, incomplete ring fusion and various side reactions, e.g., chlorination [7], or unexpected
Graphical Abstract
Scheme 1: The previously reported family of the boomerang bipyrroles obtained by Pd-induced double C–H bond a...
Scheme 2: Synthesis and structures of α-free and α-oxygenated bipyrrole boomerangs. Reagents and conditions: ...
Figure 1: DFT-Optimized structures (B3LYP/6-31G(d,p)) of cNDA2O and cNMI3H.
Figure 2: Absorption and emission spectra of cNMI2H (top) and cNMI3H (bottom) measured in toluene, dichlorome...
One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation
- Ji Ma,
- Yubin Fu,
- Junzhi Liu and
- Xinliang Feng
Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72
- exhibits a narrow energy gap (1.78 eV) and a lower LUMO energy level than the parent peropyrene without the fusion of the five-membered rings. In addition, the effects of the peri-fused pentagons on the aromaticity and molecular orbitals of 1 were evaluated by theoretical calculations. This work presents
Graphical Abstract
Scheme 1: Chemical structures of dicyclopenta-fused pyrene derivatives i–iii, peropyrene and the dicyclopenta...
Scheme 2: Synthetic route towards compound 1. a) B2pin2, dtbpy, [Ir(OMe)cod]2, cyclohexane, 70 °C, 20 h, 67%;...
Figure 1: High-resolution MALDI-TOF mass spectrum of 1. Inset: isotopic distribution compared to mass spectru...
Figure 2: Single-crystal X-ray structure of 1. (a) Top view and (b) side view of the (P,P) isomer. c) Crystal...
Figure 3: (a) UV–vis absorption spectra of precursor 5 and 1 in CH2Cl2 solution (10−5 M). Inset: photograph o...
Figure 4: Molecular orbitals of peropyrene derivative 6 and the dicyclopenta-fused peropyrene 1.
