The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

Fabclavine diversity in Xenorhabdus bacteria

• Sebastian L. Wenski,
• Harun Cimen,
• Natalie Berghaus,
• Sebastian W. Fuchs,
• Selcuk Hazir and
• Helge B. Bode

Beilstein J. Org. Chem. 2020, 16, 956–965, doi:10.3762/bjoc.16.84

• ]. Fabclavines are hexapeptide/polyketide hybrids derived from nonribosomal peptide synthetases (NRPS) and a polyketide synthase (PKS), which are connected to an unusual polyamine derived from polyunsaturated fatty acid (PUFA) synthases [20]. Beside full-length fabclavines, also shortened derivatives were

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• dried. It was demonstrated that the CuO nanoparticles–graphene hybrids could act as an effective catalyst for the “click” reaction in aqueous medium under aerobic conditions. The reusability of the catalyst CuO–GO was screened as well: the catalyst was recycled by simple filtration and washing with

Synthesis of triphenylene-fused phosphole oxides via C–H functionalizations

• Md. Shafiqur Rahman and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2020, 16, 524–529, doi:10.3762/bjoc.16.48

• nature as hybrids of triphenylene and benzo[b]phosphole. Keywords: C–H functionalization; fluorescence; phosphole; polycyclic aromatic hydrocarbons; triphenylene; Introduction The phosphorus-containing five-membered ring, phosphole, has attracted significant attention as a structural motif in π

• structurally related benzo[b]phosphole and triphenylene derivatives. The optical data illustrate the nature of compounds 8a–c as hybrids of triphenylene and benzo[b]phosphole oxide. Regarding the absorption, 8a and 8b displayed multiple absorption bands from 250–400 nm (Table 1, entries 1 and 2), which

• strong blue fluorescence in solution. The absorption and emission profiles of the π-extended phosphole oxide revealed their characteristics as hybrids of 2,3-dialkoxytriphenylene and 1-phenyl-2,3-dialkylbenzo[b]phosphole. We anticipate that the key intermediate of the present synthesis, 3, and related

Combining the Ugi-azide multicomponent reaction and rhodium(III)-catalyzed annulation for the synthesis of tetrazole-isoquinolone/pyridone hybrids

• Gerardo M. Ojeda,
• Prabhat Ranjan,
• Pavel Fedoseev,
• Lisandra Amable,
• Upendra K. Sharma,
• Daniel G. Rivera and
• Erik V. Van der Eycken

Beilstein J. Org. Chem. 2019, 15, 2447–2457, doi:10.3762/bjoc.15.237

• rhodium(III)-catalyzed intermolecular annulation has been established for the preparation of tetrazole-isoquinolone/pyridone hybrids. Several N-acylaminomethyltetrazoles were reacted with arylacetylenes to form the hybrid products in moderate to very good yields. The method relies on the capacity of the

• /pyridone hybrids by means of a reaction sequence comprising an Ugi-azide-4CR and a Rh(III)-catalyzed annulation as key steps (Scheme 1D). Results and Discussion In previous works, our group has described a variety of synthetic approaches that combine the diversity-generating character of multicomponent

• , compounds 1a–o were reacted with diphenylacetylene under the optimized catalytic conditions to furnish – eventually – the corresponding tetrazole/isoquinolone hybrids 4a–o. We first fixed the R2 substituent as H (derived from paraformaldehyde as aldehyde component in the Ugi-azide-4CR, Scheme 1) to better

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• -4CR, which is indeed one of the MCRs of major incidence in the field of steroid chemistry. Rivera and co-workers were the first to employ this 4CR for the conjugation of amino acids to steroids [19] as part of a general program for the synthesis of peptidomimetic–steroid hybrids [20][21]. As shown in

• -diketopiperazines based on a diastereoselective Ugi-4CR with an androstanic aldehyde derived from dehydroepiandrosterone (DHEA) [16]. Multicomponent synthesis of a heterocycle–steroid hybrid using a ketosteroid as carbonyl component [18]. Synthesis of peptidomimetic–steroid hybrids using the Ugi-4CR with

• with an alkynyl seco-cholestane [34]. Multicomponent synthesis of steroid–thiazole hybrids from a steroidal ketone [36]. Synthesis of cholanic pseudo-peptide derivatives by novel MCRs based on the reactivity of ynamide [37][38]. Synthesis of steroid-fused pyrimidines and pyrimidones using the Biginelli

Catalyst-free assembly of giant tris(heteroaryl)methanes: synthesis of novel pharmacophoric triads and model sterically crowded tris(heteroaryl/aryl)methyl cation salts

• Rodrigo Abonia,
• Luisa F. Gutiérrez,
• Braulio Insuasty,
• Jairo Quiroga,
• Kenneth K. Laali,
• Chunqing Zhao,
• Gabriela L. Borosky,
• Samantha M. Horwitz and
• Scott D. Bunge

Beilstein J. Org. Chem. 2019, 15, 642–654, doi:10.3762/bjoc.15.60

• ternary heteroarylmethane-inspired hybrids by coupling diversely substituted indoles (Ar1) with quinoline aldehydes, quinolone aldehydes, chromone aldehydes, and fluorene aldehydes (Ar2CHO) and coumarins (Ar3) in 1:1:1 ratio by simple reflux in ethanol solvent to form the corresponding highly crowded tris

• synthesis of ternary heteroarylmethane-inspired hybrids is presented, by coupling quinoline aldehydes, quinolone aldehydes, chromone aldehydes, and fluorene aldehydes with substituted indoles and coumarins. The method enabled the synthesis of novel libraries of giant (Ar1Ar1Ar2)CH and (Ar1Ar2Ar3)CH triads 8

• -PF6 salt 10{4,4,8}. 1D- and 2D-based NMR assignments for methylium-PF6 salt 10{4,4,11}. Optimized geometry of methylium-PF6 salts 10{4,4,8}. Optimized geometry of methylium-PF6 salt 10{4,4,11}. Representative examples of tris(hetero/aryl)methanes, molecular hybrids and bis(indolyl)methanes with useful

Synthesis and SAR of the antistaphylococcal natural product nematophin from Xenorhabdus nematophila

• Frank Wesche,
• Hélène Adihou,
• Thomas A. Wichelhaus and
• Helge B. Bode

Beilstein J. Org. Chem. 2019, 15, 535–541, doi:10.3762/bjoc.15.47

• pathogenic against humans, they are widely used as biocontrol agents in agriculture [9]. Natural products produced by bacteria play an important role in the bacteria/nematode/insect life cycle and most natural products are non-ribosomal peptides (NRP), e.g., rhabdopeptides [10][11] and polyketide–NRP hybrids

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• minor amount of homometathesis. Fortunately, the product of homocoupling could be easily separated from the desired CM products. The presence of the carborane clusters was shown to enhance the thermal stability of the materials. Absorption and emission data of carborane–POSS hybrids indicate a large red

• the range of 1.3–1.9. The surface morphology and thermal properties of hybrids were found to be affected by the POSS macromer. TEM analysis of copolymer films revealed the presence of POSS agglomerates. An analogous macromer bearing POSS-bound via phenylene linker was used in the synthesis of a series

Synthesis, biophysical properties, and RNase H activity of 6’-difluoro[4.3.0]bicyclo-DNA

• Sibylle Frei,
• Adam K. Katolik and
• Christian J. Leumann

Beilstein J. Org. Chem. 2019, 15, 79–88, doi:10.3762/bjoc.15.9

• . There, the band at 245 nm was depressed and the two positive ellipticities (≈220 nm and ≈280 nm) expressed increased intensities. Besides this, the ellipticity at 280 nm was blue-shifted (≈6 nm). All four modified DNA/RNA hybrids exhibited the characteristic shape of an intermediate A/B-type helix [48

Synthesis of indole–cycloalkyl[b]pyridine hybrids via a four-component six-step tandem process

• Muthumani Muthu,
• Rakkappan Vishnu Priya,
• Abdulrahman I. Almansour,
• Raju Suresh Kumar and
• Raju Ranjith Kumar

Beilstein J. Org. Chem. 2018, 14, 2907–2915, doi:10.3762/bjoc.14.269

• -carbonitrile hybrids 15–18 were isolated (Table 4). The structure of all the hybrid heterocycles 15–18 was elucidated using NMR spectroscopy and in the case of 16f the structure was further confirmed from single crystal X-ray studies (Figure 4) [74]. Conclusion The syntheses of a library of novel indole

• (representative cases). ORTEP diagram of 12r. ORTEP diagram of 16f. Synthesis of 3-oxopropanenitriles 3. Proposed mechanism for the formation of 7f. Synthesis of indole–cyclododeca[b]pyridine-3-carbonitriles 7 and 14. Synthesis of indole–cycloalkyl[b]pyridine-3-carbonitrile hybrids 15–18. Synthesis of indole

Synthesis of 3-aminocoumarin-N-benzylpyridinium conjugates with nanomolar inhibitory activity against acetylcholinesterase

• Nisachon Khunnawutmanotham,
• Cherdchai Laongthipparos,
• Patchreenart Saparpakorn,
• Nitirat Chimnoi and
• Supanna Techasakul

Beilstein J. Org. Chem. 2018, 14, 2545–2552, doi:10.3762/bjoc.14.231

• . Hybrid compounds such as huperzine A–tacrine hybrids [5], donepezil–tacrine hybrid related derivatives [6][7] and tacrine–indole hybrids [8] with dual-binding site properties exhibit potent AChE inhibition activities. In addition, coumarin compounds linked with various side chain moieties [9][10][11] as

Comparative cell biological study of in vitro antitumor and antimetastatic activity on melanoma cells of GnRH-III-containing conjugates modified with short-chain fatty acids

• Eszter Lajkó,
• Sarah Spring,
• Rózsa Hegedüs,
• Beáta Biri-Kovács,
• Sven Ingebrandt,
• Gábor Mező and
• László Kőhidai

Beilstein J. Org. Chem. 2018, 14, 2495–2509, doi:10.3762/bjoc.14.226

• internalize into the cells by receptor-mediated manner, where the attached drug should be released from the conjugate in order to exert its antineoplastic activity [1]. The first GnRH-drug hybrids were developed by Schally and co-workers [9]. One of their most efficient conjugates was the zoptarelin

Oligonucleotide analogues with cationic backbone linkages

• Melissa Meng and
• Christian Ducho

Beilstein J. Org. Chem. 2018, 14, 1293–1308, doi:10.3762/bjoc.14.111

• native DNA or RNA counterstrands, but with moderate destabilization relative to unmodified native duplexes, in particular for DNA–RNA hybrids. The fidelity of base pairing was studied using native DNA counterstrands containing a single base mismatch. Furthermore, structures of the duplexes were

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• fashion, they further reported a series of novel hybrids by tethering distamycin A with the antineoplastic agent uramustine via a flexible polymethylene chain of variable length (n = 1 to 6) in order to test their DNA binding affinity and cytotoxicity [57]. It has been observed that hybrid conjugates 8, 9

• anthraquinone–chalcone hybrids were synthesized using Claisen–Schmidt reaction in order to test their anticancer potential against human cancer cell lines and DNA binding affinity and specificity. It has been observed that three conjugates 32–34 exhibited significant cytotoxicity against LS174 and HeLa cancer

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• triarylboron moieties as acceptors. As possible donors, diarylamines have often been proposed (carbazole, triphenylamine, carbazole/triphenylamine hybrids, 9,9-dimethyl-9,10-dihydroacridine), as exemplified in Figure 2 [34][35][36]. In B1 and B2, isolation of the two parts was obtained by linking the 10H

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

• unique properties not observed in other classes of oligonucleotide analogues with negatively charged phosphate groups. These include the relative insensitivity of the PNA–DNA or PNA–RNA hybrids to the ionic strength of the solvent [23], and the complete stability towards nucleases as well as proteases

• labels (TAMRA/Dabcyl) at both ends of the PNA molecule and demonstrated that the fluorescence changed in response to the presence of the DNA target [43]. The high stability of PNA–PNA self-hybrids allows the design of a beacon with a relatively short stem (four bases). In this particular case, an

• probes [108][109]. The slow kinetics of the strand displacement involving highly stable PNA–DNA hybrids can be a major limitation of all the PNA-based strand displacement probes. Strand exchange can be facilitated by heating or increasing the salt concentration, where Mg2+ is more effective than Na+ [107

Synthesis and spectroscopic properties of β-meso directly linked porphyrin–corrole hybrid compounds

• Baris Temelli and
• Hilal Kalkan

Beilstein J. Org. Chem. 2018, 14, 187–193, doi:10.3762/bjoc.14.13

• Baris Temelli Hilal Kalkan Hacettepe University, Department of Chemistry, Beytepe Campus, 06800, Ankara, Turkey 10.3762/bjoc.14.13 Abstract The preparation of β-meso directly linked porphyrin–corrole hybrids was realized for the first time via an InCl3-catalyzed condensation reaction of 2-formyl

• conjugates, systematic studies on directly linked porphyrin–corrole hybrid structures are limited and there is no report on β-porphyrin, meso-corrole linked hybrids of these conjugates. Zheng et al. synthesized meso–meso directly linked porphyrin–corrole dyads by the condensation reaction of meso-formylated

Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles

• Vivek Poonthiyil,
• Thisbe K. Lindhorst,
• Vladimir B. Golovko and
• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 11–24, doi:10.3762/bjoc.14.2

• synthesize peptide-decorated AuNPs [59] and nanomaterial hybrids containing single walled carbon nanotubes and AuNPs [60]. AuNP surface modification by CuAAC The distinct advantages of CuAAC over NCAAC, such as improved regioselectivity and rates of the reaction, motivated several groups to use CuAAC for the

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• methine C-3 protons displayed in a 1H,1H-NOESY spectrum of 4 (Figure S10 in Supporting Information File 1). Compound 4 was then submitted to Cu(I)-catalyzed 1,3-dipolar cycloaddition with selected halogen-substituted and non-substituted aromatic azides to yield target N-heterocyclic hybrids 5–8 containing

Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines

• Satoru Mori and
• Norio Shibata

Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224

• possible use in PDT [99]. The deoxyribonucleoside unit is expected to enhance the water solubility of the phthalocyanine, facilitating its incorporation into cancer cells which undergo active cell division. These TFEO-ZnPc/deoxyribonucleoside hybrids were synthesized from unsymmetrical A3B-type TFEO-ZnPc

Energy down converting organic fluorophore functionalized mesoporous silica hybrids for monolith-coated light emitting diodes

• Markus Börgardts and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 768–778, doi:10.3762/bjoc.13.76

• convert the emitted UV light into light with correlated color temperatures of very cold white (41100 K, 10700 K) as well as a greenish white emission with correlated color temperatures of about 5500 K. Keywords: benzofurazane; LED; luminophores; mesoporous silica hybrids; monoliths; Nile red; perylene

• as transparent monoliths in different shapes [17][18][19]. Here, we communicate our first efforts to design red, green, and blue light-emitting mesoporous materials from organic chromophores, their blending to white light-emitting silica hybrids based upon additive color mixing, and as a proof of

• loadings of the hybrids are correlated with the surface area of the silica material, typically 700 m2·g−1, self-quenching effects should occur at loadings higher than 10 μmol·g−1 as illustrated in Figure 3 [24]. Although aggregation-induced self-quenching can be prevented by covalently ligating dye

Derivatives of the triaminoguanidinium ion, 5. Acylation of triaminoguanidines leading to symmetrical tris(acylamino)guanidines and mesoionic 1,2,4-triazolium-3-aminides

• Jan Szabo,
• Julian Greiner and
• Gerhard Maas

Beilstein J. Org. Chem. 2017, 13, 579–588, doi:10.3762/bjoc.13.57

• through hydrogen bonds with N4–H as the donor and the oxygen atom of water as the acceptor (Figure 3, right). Structural and spectroscopic characterization of 1,2,4-triazolium-3-aminides 7 The bond structure of mesoionic compounds such as 7 can be described as resonance hybrids of quite a number of

A postsynthetically 2’-“clickable” uridine with arabino configuration and its application for fluorescent labeling and imaging of DNA

• Heidi-Kristin Walter,
• Bettina Olshausen,
• Ute Schepers and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2017, 13, 127–137, doi:10.3762/bjoc.13.16

• by blue and green emitting cyanine-styryl dyes were improved due to the arabino-configured anchor. These oligonucleotides were used as energy transfer donors in hybrids with oligonucleotides modified with acceptor dyes that emit in the yellow-red range. These combinations give energy transfer pairs

• with blue–yellow, blue–red and green–red emission color changes. All combinations of arabino- and ribo-configured donor strands with arabino- and ribo-configured acceptor strands were evaluated. This array of doubly modified hybrids was screened by their emission color contrast and fluorescence quantum

• first report [21]. The orientation of the 2’-OH group in the arabino configuration towards the major groove yields hybrids with RNA that show a slightly lower thermal stability compared to DNA/RNA hybrids. In order to evaluate this structural influence for our fluorescently labelled oligonucleotides, we

Diastereoselective anodic hetero- and homo-coupling of menthol-, 8-methylmenthol- and 8-phenylmenthol-2-alkylmalonates

• Matthias C. Letzel,
• Hans J. Schäfer and
• Roland Fröhlich

Beilstein J. Org. Chem. 2017, 13, 33–42, doi:10.3762/bjoc.13.5

• compound 23b (Figure 2) and converting the sp3 hybridized carbon atoms C2’ and C3’ into sp2 hybrids shows that the minor stereoisomer is formed by the shielding of the re-face through the tert-butyl group. Hence the major diastereomer 23a is formed by an attack via the less shielded si-face. The same