- [(Diphenoxyphosphinyl)methylidene]triphenylphosphorane - The double P +-stabilised carbanion: A crystallographic, computational and solution NMR comparative study on the ylidic bonding
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The crystal and molecular structure of the title compound (1) was established by an X-ray diffraction analysis. Some geometrical parameters including a slightly pyramidal shape around its ylidic Cβ-atom were determined (trans-bent type conformation), providing evidence for a strong electron delocalisation in the PαCβP γOδ backbone. The charge density redistribution within this molecular unit and its other fully optimised geometries was evaluated in ab initio MO calculations using both the HF and DFT (B3LYP) formalism, which supported such a concept. As a result, the double zwitterionic form (structure C) was suggested as the best description of 1. The absence of an experimentally NMR observable 2JPα-Cβ -Hβ coupling was tentatively rationalised in terms of fast pyramidalisation of the Cβ-anionic site. Crystallographic and solution NMR data for ylide 1 were compared with those reported for the other mesomerically stabilised Wittig-type reagents and structurally related anionic species. It was concluded that all aforementioned systems have almost identical P-ylidic bonding most likely governed mainly by very strong electrostatic interactions, with a small contribution of negative hyperconjugation.
- Ch?cińska, Lilianna,Kudzin, Zbigniew H.,Ma?ecka, Magdalena,Nazarski, Ryszard B.,Okruszek, Andrzej
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- Reactions of α-aminoalkylphosphonates with iso(thio) cyanatophosphates(phosphonates, phosphinates). Synthesis of 1,3,4- diazaphospholidines and 1,3,4-oxaza(thiaza)phospholines
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Phenyl α-aminoalkylphosphonates add to phenyl iso(thio)cyanates to give saturated heterocycles, 1,3,4-diazaphospholidin-2-(thi)ones. The reaction of diphenyl (α-methylamino)benzylphosphonate with diethyl isothiocyanatophosphate involves initial formation of 1,3,4-tiazaphospholidine- 2-thiones containing exo- and endocyclic phosphorus atoms. These products are readily hydrolyzed in air, yielding diethyl isothiocyanatophosphate and phenyl hydrogen (α-methylamino)benzylphosphonate. The final products of the reaction of chloromethyl isocyanatophosphonates with aminoalkylphosphonates are 1,3,4-oxazaphospholines. Phenyl aminoalkylphosphonates react with chloromethyl isocyanatophosphonates to give saturated heterocycles, 1,3,4- diazaphospholidines, whereas with chloromethyl isothiocyanatophosphonates 1,3,4-thiazaphospholines are formed.
- Khailova,Shaimardanova,Saakyan,Zyablikova,Azancheev,Krivolapov,Gubaidullin,Litvinov,Musin,Chmutova,Pudovik,Pudovik
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- The molecular structure of chloromethylphosphine, CClH2PH2, as determined by gas-phase electron diffraction and ab initio computations
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The gas-phase structure of chloromethylphosphine, CClH2PH2, has been determined by electron diffraction employing constraints derived from ab initio computations at the CISD(fc)/6-31+G** level.At 293 K, the compound exists in two conformations, anti and gauche (phosphorus lone pair relative to the C-Cl bond); the mole fraction of the gauche conformer is 0.22(5).Important experimental structural parameters (rg/pm, /deg) for the anti and gauche conformers, respectively, are (values without e.s.d.s. indicate that the difference between the parameters for the two conformers was fixed at the theoretical value): r(C-P) = 186.3(3), 187.4; r(C-Cl) = 179.1(5), 179.0; r(P-H) = 141.5(4), 142.9; PCCl = 115.7(1), 107.8(5) .The large difference between the PCCl angles in the conformers can be rationalised on the basis of overlaps between non-bonding and antibonding molecular orbitals.
- Brain, Paul T.,Rankin, David W. H.,Robertson, Heather E.,Downs, Anthony J.,Greene, Tim M.,et al.
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- Reaction of chloromethyliso(thio)cyanato(thio)phosphonates(-phosphinates) with phenol, ethanol, and thiols
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(Chloromethyl)isocyanatophosphonates(-phosphinates) take up phenol to form carbamates whose β-cleavage gives rise to phenyl (chloromethyl) phosphonates(-phosphinates). (Chloromethyl)(thio)phosphinic-(phosphonic) isothiocyanates react with phenol at 20°C in the absence of catalyst to afford phenyl phosphinates(-phosphonates). (Alkylsulfanyl)carbamates formed by addition of thiols to (chloromethyl)iso(thio)cyanastophosphonates(-phosphinates) under the action of an equimolar amount of triethylamine undergo cyclization into 1,3,4-oxaza(thiaza)phospholines. 2004 MAIK "Nauka/ Interperiodica".
- Khailova,Bagautdinova,Shaimardanova,Krepysheva,Pudovik,Chmutova,Azancheev,Musin,Pudovik
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p. 1335 - 1340
(2007/10/03)
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- Synthesis and Properties of Some Derivatives of (Chloromethyl)phosphonic and Bis(chloromethyl)phosphinic Acids
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(Chloromethyl)phosphonic(phosphinic) chlorides were reacted with primary amines and hepta-methyldisilazane to obtain the corresponding amides. The reaction of phenyl N-methyl-N-(trimethylsilyl)-(chloromethyl)phosphonamidate with phenyl isocyanate involves intermediate formation of phosphorylated urea which undergoes cyclization into 1,4,2-diazaphospholidin-5-one. The reaction with benzaldehyde occurs by β cleavage, yielding trimethylsilyl (chloromethyl)phosphonate. Phosphorylation of amides and silylamides of (chloromethyl)phosphonic(phosphinic) acids with four-coordinate phosphorus acid chlorides was studied.
- Pudovik,Terent'eva,Pudovik
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- Synthesis of certain nucleoside methylenediphosphonate sugars as potential inhibitors of glycosyltransferases
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The synthesis of α-D-glucopyranosyl 1-(methylenediphosphonate) (11), α-D-galactopyranosyl 1-(methylenediphosphonate) (14), and α-D-mannopyranosyl 1-(methylenediphosphonate) (17) has been accomplished. [(Diphenoxyphosphinyl)methyl]phosphonic acid (diphenyl-MDP) (5), synthesized by two different procedures, was fused with β-D-glucopyranose pentaacetate followed by catalytic hydrogenation to give 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl methylenediphosphonate (glucose-MDP) (10). The anomeric configuration of 10 was assigned on the basis of NMR spectral studies. Condensation of 10 with 2',3'-di-O-acetyladenosine was accomplished by using 1-(mesitylene-2-sulfonyl)-3-nitro-1,2,4-triazole (MSNT) as coupling agent, and removal of the blocking groups gave adenosine 5'-[(α-D-glucopyranosylhydroxyphosphinyl)methyl]phosphonate (20). Uridine 5'-[(α-D-galactopyranosylhydroxyphosphinyl)methyl]phosphonate (23) and guanosine 5'-[(α-D-mannopyranosylhydroxyphosphinyl)methyl]phosphonate (26) were similarly prepared. Using a specific glycoprotein galactosyltransferase (EC 2.4.1.38) assay, uridine 5'-[(α-D-galactopyranosylhydroxyphosphinyl)methyl]phosphonate (23) demonstrated competitive inhibition with an apparent K(i) of 97 μM. The adenosine analogue did not inhibit the enzyme. None of the above compounds show any in vitro antitumor or antiviral activity. Such specific inhibitors of glycosyltransferases may serve as specific probes to study various glycosyltransferases that might be involved in the process of metastasis.
- Vaghefi,Bernacki,Hennen,Robins
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p. 1391 - 1399
(2007/10/02)
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