Synthesis of C-glycosyl phosphonate derivatives of 4-amino-4-deoxy-α-ʟ-arabinose

• Lukáš Kerner and
• Paul Kosma

Beilstein J. Org. Chem. 2020, 16, 9–14, doi:10.3762/bjoc.16.2

• have frequently been exploited as potential inhibitors for glycosyl transferases since the carbon–phosphorus bond is not hydrolyzed in the active site of glycosyl transferases [10][11][12][13]. Herein, we report on the synthesis of α-anomeric C-arabinosyl methylphosphonate ester derivatives as model

• carbon atom as well as signals of two upfield-shifted deoxy protons at 2.72 and 2.55 ppm, respectively, to the anomeric carbon atom. In addition, for compound 10, lacking the conjugation to the phosphorus atom, a significant downfield shift of the 31P NMR signal was observed (17.97 ppm in 10 versus 10.95

• 14 as the minor isomer in 17% yield. The HPLC-based purification step even allowed for further separation of the diastereomers on phosphorus of both compounds. Selective methyl ester cleavage of 12 and 14 – again using NaI in a minimum volume of acetone – was straightforward and furnished the octyl

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• synthesized chiral compounds based on phosphorus esters and investigated their effects as chiral auxiliaries in the α-alkylation of secondary amines via anodic oxidation [100]. The constant current methoxylation of N-protected chiral pyrrolidines 173 in an undivided cell resulted in 174 in excellent yield

1,5-Phosphonium betaines from N-triflylpropiolamides, triphenylphosphane, and active methylene compounds

• Vito A. Fiore,
• Chiara Freisler and
• Gerhard Maas

Beilstein J. Org. Chem. 2019, 15, 2603–2611, doi:10.3762/bjoc.15.253

• bonding situation in annelated oxaphospholes 8 (Scheme 7) is best described by the contribution of two canonical structures: an oxaphosphole 8A with a pentacovalent phosphorus atom and a P–O bond, and a betaine structure 8B with a phosphonium group and a P···O distance that varies with the electronic

• III (Scheme 1) (PR3 = PMe2Ph, R’ = Ph, 2.597 and 2.620 Å in two symmetry-independent molecules [15]). Furthermore, the coordination around the phosphorus atom comes close to a trigonal-pyramidal geometry with the oxygen and the carbon atom C13 in apical positions: the angle O···P–C13 is 177.1° and the

• sum of bond angles involving atoms C1, C19 and C25 in the equatorial plane is 346.8o (compared to 328.4° for an ideal tetrahedral coordination). All these data point to the description of Z-3e as a 1,5-betaine with an attractive electrostatic interaction of phosphorus and oxygen. The 31P NMR chemical

Chiral terpene auxiliaries V: Synthesis of new chiral γ-hydroxyphosphine oxides derived from α-pinene

• Anna Kmieciak and
• Marek P. Krzemiński

Beilstein J. Org. Chem. 2019, 15, 2493–2499, doi:10.3762/bjoc.15.242

• site providing a trans relationship between the hydroxy and the phosphine substituents. Keywords: isopinocamphone; monoterpenes; phosphines; [2,3]-sigmatropic rearrangement; verbanone; Introduction Chiral phosphorus compounds, despite many years of research, still enjoy unflagging interest of many

• research groups [1]. Compounds with a phosphorus atom attached to a stereogenic carbon center in acyclic and cyclic structures play an important role as chiral ligands in transition metal complexes [2]. They were applied to various catalytic asymmetric reactions [3][4], such as hydrogenations [3][4][5][6

Fluorescent phosphorus dendrimers excited by two photons: synthesis, two-photon absorption properties and biological uses

• Anne-Marie Caminade,
• Artem Zibarov,
• Eduardo Cueto Diaz,
• Aurélien Hameau,
• Maxime Klausen,
• Kathleen Moineau-Chane Ching,
• Jean-Pierre Majoral,
• Jean-Baptiste Verlhac,
• Olivier Mongin and
• Mireille Blanchard-Desce

Beilstein J. Org. Chem. 2019, 15, 2287–2303, doi:10.3762/bjoc.15.221

• Different types of two-photon absorbing (TPA) fluorophores have been synthesized and specifically functionalized to be incorporated in the structure of phosphorus dendrimers (highly branched macromolecules). The TPA fluorophores were included in the periphery as terminal functions, in the core, or in the

• the mechanism of action of anticancer compounds, and for safer photodynamic therapy. Keywords: bioimaging; dendrimer; fluorescence; phosphorus; two-photon absorption; Introduction Natural luminescence phenomena such as the bioluminescence of fireflies or of certain marine microorganisms, or the

• enhancement of TPA responses [17][18][19][20][21]. Phosphorus-containing dendrimers [22], mainly of the phosphorhydrazone type [23], stand out among all the other types of dendrimers by their properties [24], in particular in biology [25][26] and their highly modular structure [27]. Indeed, different types of

Synthesis of ([1,2,4]triazolo[4,3-a]pyridin-3-ylmethyl)phosphonates and their benzo derivatives via 5-exo-dig cyclization

• Aleksandr S. Krylov,
• Artem A. Petrosian,
• Julia L. Piterskaya,
• Nataly I. Svintsitskaya and
• Albina V. Dogadina

Beilstein J. Org. Chem. 2019, 15, 1563–1568, doi:10.3762/bjoc.15.159

• ]thiadiazole [2], and benzo[4,5]imidazo[2,1-b]thiazole [3], as well as due to the simultaneous presence of a biologically active phosphorus function in the molecules. Recently, we have shown that the reaction of chloroethynylphosphonates with 2-aminopyridines proceeds through a 5-endo-dig cyclization to form

• one method for the formation of a [1,2,4]triazolo[4,3-a]pyridine ring with participation of an acetylene triple bond; an oxidative cyclization during the reaction of terminal phenylacetylenes with 2-hydrazinylpyridines [14]. However, data on phosphorus-containing triazolopyridines are scarce, although

• . Chemical shifts of the phosphorus nucleus for compounds 3–8 were registered in the range of δP 22–23 and 18–19 ppm for dimethyl а and diisopropyl phosphonates b, respectively. In the 1Н NMR spectra of products 3–8, the methylene unit was recorded as a doublet signal (δH 3.42–4.19 ppm) with a spin–spin

Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids: a crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates

• Stanislav V. Lozovskiy,
• Alexander Yu. Ivanov and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1491–1504, doi:10.3762/bjoc.15.151

• phosphonic acids and other phosphorus-containing compounds. Contrary to Brønsted acids, 3-methylbuta-1,2-dien-1-ylphosphonic dichloride [Cl2(O=)P–HC=C=CMe2] reacted with the Lewis acid AlCl3 in an intermolecular way forming noncyclic intermediates, which were investigated by NMR spectroscopy and DFT

• substituents at the phosphorus atom of phosphorylallenes [13][14][15][16]. These cations were intermediates in Brønsted and Lewis acid-promoted intramolecular reactions of phosphorus-containing allenes with aromatic π-nucleophiles giving rise to various (bi)cyclic phosphorus-containing compounds [13][14][15

• species E1 (δ 53 ppm) and E2 (δ 43 ppm). This difference may reveal that phosphorus in cation E4 is bound to a carbon atom, rather than to a heteroatom O or N, like in E1 and E2. Structurally close six-membered ring cations, having the C–P bond, resonate at 30.5–31.9 in 31P NMR [16], that is close to the

Microwave-assisted synthesis of N,N-bis(phosphinoylmethyl)amines and N,N,N-tris(phosphinoylmethyl)amines bearing different substituents on the phosphorus atoms

• Erika Bálint,
• Anna Tripolszky,
• László Hegedűs and
• György Keglevich

Beilstein J. Org. Chem. 2019, 15, 469–473, doi:10.3762/bjoc.15.40

• phosphorus atoms was synthesized by the microwave-assisted and catalyst-free Kabachnik–Fields reaction of (aminomethyl)phosphine oxides with paraformaldehyde and diphenylphosphine oxide. The three-component condensation of N,N-bis(phosphinoylmethyl)amine, paraformaldehyde and a secondary phosphine oxide

• now. In this paper, we report the efficient, catalyst-free and MW-assisted synthesis of N,N-bis(phosphinoylmethyl)amine and N,N,N-tris(phosphinoylmethyl)amine derivatives bearing different substituents on the phosphorus atoms. Results and Discussion Synthesis of N,N-bis(phosphinoylmethyl)alkylamines

• containing different substituents on the phosphorus atoms First, the (aminomethyl)phosphine oxide starting materials 5–7 were synthesized following our previous protocol [11]. Thus, the MW-assisted Kabachnik–Fields reaction of primary amines (butyl-, cyclohexyl- or benzylamine), paraformaldehyde and di(p

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

• is most commonly modified to generate the phosphorylated derivative of NR+, nicotinamide mononucleotide, NMN. The phosphorylation is achieved by reacting NR+ in its salt form with phosphorus oxychloride in trimethyl phosphate resulting, after hydrolysis, in NMN (Scheme 17). Lee et al. [27] carefully

• group and – after quenching with water – to give NMN analogues with one alkoxy group at the phosphorus atom. The resulting compounds were purified by column chromatography on an aminopropyl-modified silica gel Quadrasil AP column to yield the pure NMN analogues in low to moderate yields (8–40%). The

• patent publication of Sauve et al. [59] divulges phosphorylation of isopro-NR+ 29 (as triflate salt) with phosphorus oxychloride in trimethyl phosphate at 0 °C for 48 h to give isopro-NMN 33 in 80% yield (Scheme 18) after silica gel column chromatography using a 6:4 DCM/MeOH mixture as an eluent

Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes

• Guillaume Ernouf,
• Jean-Louis Brayer,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2019, 15, 333–350, doi:10.3762/bjoc.15.29

• that observed for 7a/7’a. Other substituents were tolerated on the phosphorus atom including an isopropyl or a cyclohexyl group and the corresponding phosphine oxides 7h/7’h and 7i/7’i were isolated in good yields. Increasing the steric hindrance around the phosphorus atom resulted in a higher

• mechanism (Scheme 8) [37]. To date and to the best of our knowledge, reports on [2,3]-sigmatropic rearrangements of cyclopropenylcarbinol derivatives appear to be limited to the synthesis of alkylidenecyclopropanes incorporating a phosphorus atom. Cyclopropenylcarbinol derivatives can also lead to other

Pd-Catalyzed microwave-assisted synthesis of phosphonated 13α-estrones as potential OATP2B1, 17β-HSD1 and/or STS inhibitors

• Rebeka Jójárt,
• Szabolcs Pécsy,
• György Keglevich,
• Mihály Szécsi,
• Réka Rigó,
• Csilla Özvegy-Laczka,
• Gábor Kecskeméti and
• Erzsébet Mernyák

Beilstein J. Org. Chem. 2018, 14, 2838–2845, doi:10.3762/bjoc.14.262

• [29]; namely, 1 equiv in the case of Pd(PPh3)4 and 1.3 equiv when using Pd(OAc)2. It was earlier established that in the microwave-assisted Pd(II)-catalyzed C–P coupling of aryl bromides and dialkyl phosphites, an excess of the applied dialkyl phosphite may serve as phosphorus ligand and reducing

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• graphite powder (141), potassium persulfate, phosphorus pentoxide, and sulfuric acid was heated at 80 °C for 2 h. The resulted solid was filtered and washed with water, methanol, and ether. Then, the obtained black paste was dried. After mixing the resulting material with sulfuric acid at 0 °C, potassium

Quinolines from the cyclocondensation of isatoic anhydride with ethyl acetoacetate: preparation of ethyl 4-hydroxy-2-methylquinoline-3-carboxylate and derivatives

• Nicholas G. Jentsch,
• Jared D. Hume,
• Emily B. Crull,
• Samer M. Beauti,
• Amy H. Pham,
• Julie A. Pigza,
• Jacques J. Kessl and
• Matthew G. Donahue

Beilstein J. Org. Chem. 2018, 14, 2529–2536, doi:10.3762/bjoc.14.229

• milligrams were met with inconsistent results and variable yields. In our experience, this route is less advantageous due to: (1) the need for a prolonged room temperature condensation reaction time (>5 days in a desiccator with phosphorus pentoxide) to form the initial vinylogous amide; (2) the use of

• the undesired quinoline 12. We then turned to a functional group transformation of the ethyl ester at the 3-position to address the acetic acid sidechain problem (Scheme 7). First, the 4-hydroxy group in quinoline 10f was substituted for chlorine with neat phosphorus oxychloride to afford chloride 14

Non-metal-templated approaches to bis(borane) derivatives of macrocyclic dibridgehead diphosphines via alkene metathesis

• Tobias Fiedler,
• Michał Barbasiewicz,
• Michael Stollenz and
• John A. Gladysz

Beilstein J. Org. Chem. 2018, 14, 2354–2365, doi:10.3762/bjoc.14.211

• H3B·P(n-C8H17)3 (1%), H3B·P((CH2)13CH2)(n-C8H17) (8%; see text for tie bars that indicate additional phosphorus–carbon linkages, which are coded in the abstract with italics), H3B·P((CH2)13CH2)((CH2)14)P((CH2)13CH2)·BH3 (6·2BH3, 10%), in,out-H3B·P((CH2)14)3P·BH3 (in,out-2·2BH3, 4%) and the stereoisomer

• somewhat higher overall yields, as analyzed elsewhere [1][2][3][4]. Setaka has developed a similar chemistry in which the phosphorus atoms are replaced by silicon and the metal fragment by p-phenylene (p-C6H4) or related aromatic moieties [14][15][16][17][18][19]. These types of compounds are viewed as

• series for additional details [22][25][28][29][30]. Interconversions between the in,in/out,out and in,out/out,in manifolds require phosphorus inversion and temperatures considerably in excess of 100 °C. In this paper, we describe two non-metal-templated approaches to 2 that are based upon metatheses of

Coordination-driven self-assembly of discrete Ru₆–Pt₆ prismatic cages

• Aderonke Ajibola Adeyemo and
• Partha Sarathi Mukherjee

Beilstein J. Org. Chem. 2018, 14, 2242–2249, doi:10.3762/bjoc.14.199

• considerably shifted (Figure 1 and Supporting Information File 1, Figure S14). The appearance of a singlet peak in the 31P NMR evidenced the formation of a single product and the fact that the phosphorus moieties are in the same chemical environment (Supporting Information File 1, Figures S15 and S16). The

Anomeric modification of carbohydrates using the Mitsunobu reaction

• Julia Hain,
• Patrick Rollin,
• Werner Klaffke and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1619–1636, doi:10.3762/bjoc.14.138

• pathway A or B as depicted in Scheme 2. Especially when the sugar alcohol is not sterically hindered, phosphorus transfer occurs to yield a phosphine-activated anomeric alcohol (a glycosyloxyphosphonium ion, pathway A). This in turn can be attacked by the deprotonated nucleophile resulting in an

Cobalt–metalloid alloys for electrochemical oxidation of 5-hydroxymethylfurfural as an alternative anode reaction in lieu of oxygen evolution during water splitting

• Jonas Weidner,
• Stefan Barwe,
• Kirill Sliozberg,
• Stefan Piontek,
• Justus Masa,
• Ulf-Peter Apfel and
• Wolfgang Schuhmann

Beilstein J. Org. Chem. 2018, 14, 1436–1445, doi:10.3762/bjoc.14.121

• foam, Ni2P and Ni3S2 on nickel foam, in a one compartment batch type electrochemical reactor [5][28][29]. We recently reported on the synthesis and application of alloys of cobalt with boron and phosphorus as exceptionally active bifunctional HER/OER catalysts for water splitting. Inspired by these

• comparatively lower potential than that required for water oxidation. Suitable catalysts are, however, required to achieve a selective oxidation of HMF to FDCA with a high conversion yield. We recently demonstrated that the modification of cobalt with boron and phosphorus alters the electronic and lattice

• Te), could likewise lead to an enhanced electrocatalysis for reactions other than the OER and the HER. To this end, alloys of cobalt with boron, silicon, phosphorus, arsenic and tellurium were screened for their electrocatalytic activity for HMF oxidation. A detailed synthetic procedure to afford

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

• pure form, i.e., with defined configuration at the stereogenic phosphorus atom [47]. Corresponding RP-configured zwitterionic oligonucleotides formed duplexes with complementary DNA or RNA that were more stable than their respective native counterparts. The modified oligonucleotides showed pronounced

• range and its ability to form both intermolecular electrostatic interactions and hydrogen bonds [50]. Letsinger's aminoalkyl phosphoramidate modification was stereogenic at the phosphorus atom, thus leading to complex mixtures of diastereomeric oligomers (with the exception of the aforementioned related

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

Mechanochemistry of nucleosides, nucleotides and related materials

• Olga Eguaogie,
• Joseph S. Vyle,
• Patrick F. Conlon,
• Manuela A. Gîlea and
• Yipei Liang

Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81

• development of DNA purification which featured mechanochemistry at low temperatures [59]. Miescher reported grinding the solid residues from defatted salmon sperm heads with dilute HCl (0.5%) to effect such a separation and was able to report elemental analysis of nuclein with a phosphorus content (9.6

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

• action of metal ions and to construct models for catalytic centers [11][18]. Review Basic principles of phosphoryl transfer reactions Non-enzymatic cleavage of phosphodiester linkages of nucleic acids proceeds by an intra- (RNA) or intermolecular (DNA) nucleophilic attack on phosphorus. The reaction

• an equatorial position. Bulky ligands tend to be equatorial. If two of the oxygen atoms are bridged by an ethylene group, as in the phosphorane obtained by the attack of 2´-OH of RNA on phosphorus, one must be apical and the other equatorial. A sufficiently stable phosphorane may, however, undergo a

• intermediate [31]. The lifetime for the dianionic pentacoordinated species obtained by the attack of the hydroxide ion on the phosphorus has been argued to represent an energy minimum between the transition states for the attack of HO− and the departure of EtO− and to have a lifetime of 1 picosecond. With

Liquid-assisted grinding and ion pairing regulates percentage conversion and diastereoselectivity of the Wittig reaction under mechanochemical conditions

• Kendra Leahy Denlinger,
• Lianna Ortiz-Trankina,
• Preston Carr,
• Kingsley Benson,
• Daniel C. Waddell and
• James Mack

Beilstein J. Org. Chem. 2018, 14, 688–696, doi:10.3762/bjoc.14.57

• , and 5 indicates that the carbonate bases deprotonated the phosphonium salt to form the ylide which then subsequently added to the benzaldehyde. However, the oxygen anion could not bind to the phosphorus cation to produce the stilbene product, presumably due to the mismatched counter ion pair. After

Copper-catalyzed asymmetric methylation of fluoroalkylated pyruvates with dimethylzinc

• Kohsuke Aikawa,
• Kohei Yabuuchi,
• Kota Torii and
• Koichi Mikami

Beilstein J. Org. Chem. 2018, 14, 576–582, doi:10.3762/bjoc.14.44

• ) groups in good-to-high yields and enantioselectivities. Axial backbones and substituents on phosphorus atoms of chiral phosphine ligands critically influence the enantioselectivity. Moreover, the methylation of simple perfluoroalkylated ketones is found to be facilitated by only chiral phosphines without

• enantioselectivities, and (CuOTf)·C6H6 and CuI led to a racemic product (Table 1, entries 2–4). Chiral phosphine ligands instead of BINAP were further assayed with the aim of enhancing the enantioselectivity. Indeed, the investigation of the effect of axial backbones and substituents on the phosphorus atoms led to an

• increase in the enantioselectivity. In the case of a biphenyl backbone, MeO-BIPHEP showed the same level of enantioselectivity as BINAP, while lower enantioselectivity was obtained by SEGPHOS (Table 1, entries 5 and 6). Exploring the effect of substituents on phosphorus, DM-BINAP slightly exceeded the

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• up to 94% yields. Shinde et al. also published iodine catalysis carried out at room temperature in DCE [45]. Whereas long reaction times were needed in the latter process, good yields could be achieved under mild conditions. In additional publications listed in Table 1, entries 42–64, phosphorus

• pentoxide (P2O5) [46], silica-supported phosphorus pentoxide (P2O5-SiO2) [47], N,N,N’,N’-tetrabromobenzene-1,3-disulfonamide (TBBDA) [48], 1-methyl-3-(2-(sulfoxy)ethyl)-1H-imidazol-3-ium chloride (MSI) [49], succinic acid [50], tannic acid [49], p-nitrobenzoic acid [52], a carbon-based solid acid (CBSA) [53

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• (5H)-one derivatives 204 by refluxing in 1 N sodium hydroxide. Pyrazolo[3,4-d]pyrimidinone 204 were further chlorinated by phosphorus oxychloride and subsequently converted to carboxylic esters 207 via cyanation followed by hydrolysis and esterification. Kaplan et al. [20] explored the synthesis of

• . Chlorination of pyrazolo[3,4-d]pyrimidine derivative 211 with phosphorus oxychloride afforded 4-chloro-1H-pyrazolo[3,4-d]pyrimidine derivative 212. The chloro and nitro groups were manipulated to introduce a 3,6-dihydropyran group at position-4 by Stille reaction which provided 4-(4-(3,6-dihydropyran-4-yl)-1H