Reduction of n-(1,3-dioxolan-2-yl)-1-methylpyridinium ions: Molecular structure of the 4-(l,3-dioxolan-2-yl)-1-methyl-1,2,3,6-tetrahydropyridine-borane complex

The reduction of the n-(1,3-dioxolan-2-yl)-1-methylpyridinium ions with sodium borohydride has been studied to prepare N-methylformylpiperidines. Deuterium oxide was used as the solvent in order to assign the protons in the nmr spectra. As a product of the reaction, the 4-(1,3-dioxolan-2-yl)-1-methyl-1,2,3,6-tetrahy-dropyridine-borane complex, was isolated and crystallized. A X-ray study of this borane complex has been carried out.     

Synthesis of Novel 1,3-Dioxolane Nucleoside Analogues

Novel 1,3-dioxolane C-nucleoside analogues of tiazofurin 2-(2-hydroxymethyl-1,3-dioxolan-4-yl)-1,3-thiazole4-carboxamide as well as N-nucleoside analogues of substituted imidazoles 1-(2-hydroxymethyl-1,3-dioxolan4-yl)-4-nitroimidazole and 1-(2-hydroxymethyl-1,3-dioxolan-4-yl)-4,5-dicyanoimidazole were synthesized from methyl acrylate through a multistep procedure. Their structures were confirmed by IR,^1H NMR,^13C NMR spectraand elemental analysis.     

Synthesis of 3-(N-alkylamino)acetophenones via a benzyne intermediate

Reaction of 2-(2-bromophenyl)-2-methyl-1,3-dioxolane with lithium (1,1-dimethylethyl)amide, lithium (2,2-dimethylpropyl)amide, lithium (1,1-dimethylpropyl)amide gave the corresponding N-(alkyl)-3-(2-methyl-1,3-dioxolan-2-yl)benzenamines in moderate yields. 1-[3-[(1,1-Dimethylethyl)amino]phenyl]ethanone ( 4 ) was prepared in over 80% yield from 2-(2-bromophenyl)-2-methyl-1,3-dioxolane ( 2 ).     

Fluorinated dioxolanes. 3. Nucleophilic reactions of perfluoro-4-methyl-1,3-dioxolanes

Conclusions Perfluoro-2,4-dimethyl-2-fluorocarbonyl-1,3-dioxolane reacts with sodium carbonate to give perfluoro-2-methylene-2-methyl-1,3-dioxolane. Under the reaction conditions, the latter dimerizes to perfluoro-2-(2,4-dimethyl-1,3-dioxolan-2-ylmethylene)-4-methyl-1,3-dioxolane, and on treatment with CsF is converted into perfluoromethyl-(1,3-dioxolany-2-yl)ketone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 938–942, April, 1989.     

Synthesis of New 1,3-Thiazolecarbaldehydes

H-Lithiation and Br-lithiation reactions of 1,3-thiazole were studied in order to obtain new thiazole derivatives. Four isomeric chloromethyl derivatives of 1,3-thiazole containing a protected aldehyde group like 2-(1,3-dioxolan-2-yl)-5-(chloromethyl)-1,3-thiazole, 5-(1,3-dioxolan-2-yl)-2-(chloromethyl)-1,3-thiazole, 4-(1,3-dioxolan-2-yl)-2-(chloromethyl)-1,3-thiazole, and 2-(1,3-dioxolan-2-yl)-4-(chloromethyl)-1,3-thiazole were synthesized. Their nucleophilic substitution reactions with dimethylamine and sodium methylthiolate were studied. New aldehydes of 1,3-thiazole series of low-molecular weight were obtained.     

Synthesis of 1-[3-methyl-2(3H)-benzazolon-5- or 6-yl]-4-{4-[cis-2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl-methyl)-1,3-dioxolan-4-yl]methyleneoxyphenyl}piperazines

Reactions of 3-methyl-6-[4-(4-hydroxyphenyl)-1-piperazinyl]-2(3H)-benzoxazolone, 3-methyl-6-[4-(4-hydroxy-phenyl)-1-piperazinyl]-2(3H)-benzothiazolone and 1,3-dimethyl-5-[4-(4-hydroxyphenyl)-1-piperazinyl]-2(3H)-benzimidazolone with cis-{[2-(2,4-dichlorophenyl) -2-(1H-imidazol-1-ylmethyl)]-1,3-dioxolan-4-yl}methyl meth-anesulfonate in the presence of sodium hydride furnish the title compounds.     

Effect of the β-substituent with respect to the azido group on the reactivity of methyl (2E)-3-[5-(azidomethyl)-2,2-diethyl-1,3-dioxolan-4-yl]-2-methylprop-2-enoate

Unlike methyl (2E)-3-[5-(azidomethyl)-2,2-diethyl-1,3-dioxolan-4-yl]-2—methylprop-2-enoate which is stable on storage, its acyclic derivative, methyl (2E,4S,5S)-6-azido-5-hydroxy-2-methyl-4-(pent-3-yloxy) hex-2-enoate at 20°C undergoes unusual decomposition with formation of exo-methylidenepyrrolidine. Analogous transformation was also observed in the epoxide ring opening in methyl (2E)-2-methyl-4-[(S)-oxiran-2-yl]-4-(pent-3-yloxy)but-2-enoate and in the substitution reaction of ethyl 5,6-bis(methanesulfonyloxy)-2-methyl-4-(pent-3-yloxy)hex-2-enoate with azide ion. Opening of the oxirane ring in the former by the action of azide ion was accompanied by formation of oxazetidine derivative as a minor product. The major intramolecular cyclization products, 4-hydroxy- and 4-mehtanesulfonyloxypyrrolidines were converted into stable pyrrole derivatives via elimination of the leaving groups. The hydrogenation of methyl and ethyl (2E)-3-[5-(azidomethyl)-2,2-diethyl-1,3-dioxolan-4-yl]-2-methylprop-2-enoates over palladium catalyst afforded the expected reduction products.     

Design and synthesis of novel dinucleotide analogs

Syntheses of dinucleotide analogs, (S,R) cis-(4-((4-amino-2-oxopyrimidin-1(2H)-yl)methyl)-1,3-dioxolan-2-yl)methyl (2R,3R,5R)-2-(hydroxymethyl)-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-tetrahydrofuran-3-yl hydrogen phosphate (5a) and (S,R) cis-(5-((4-amino-2-oxopyrimidin-1(2H)-yl)methyl)-1,3-oxathiolan-2-yl)methyl (2R,3R,5R)-2-(hydroxymethyl)-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-tetrahydrofuran-3-yl hydrogen phosphate (5b), were accomplished by the use of a new strategy. The use of phenyldichlorophosphate (Method A) as the coupling reagent was shown to possess superiority relative to the reported use of di(1H-benzo[d][1,2,3]triazol-1-yl)phenyl phosphonate (Method B).     

Photocrosslinking of poly(methyl acrylate)s containing the 1,3-dioxolane structure as a pendant group

(2-Ethyl-2-methyl-1,3-dioxolan-4-yl)methyl- and (2-methyl-2-phenyl-1,3-dioxolan-4-yl) methyl acrylates were synthesized and polymerized. The photochemical behavior of the resulting polymers was investigated to determine whether the polymers pending on the 1,3-dioxolane structure were readily crosslinked with ultraviolet (UV) irradiation. The degree of crosslinking was estimated by the weight-loss method by immersion in acetone, with the result that the polymer with an aromatic substituent was more photocrosslinkable than the polymer that bore the aliphatic substituent. The catalytic effect on photocrosslinking of polymers was also studied by using benzoin and cobalt naphthenate. The infrared (IR) spectra of polymers irradiated in air that showed the new band at 3450 cm^?1 were attributed to a hydroxyl group; however, the spectra of polymers irradiated in vacuum displayed little absorption at 3450 cm^?1. To explain the mechanism of crosslinking model compounds were prepared and irradiated with UV light. It was concluded that crosslinking proceeds mainly from the fission of the 1,3-dioxolane ring and the coupling of the yielding radicals, together with autooxidation by atmospheric oxygen.     

Reactions of 4-methylidenedioxolan-2-ones with 2-methyltryptamines. Synthesis of core analogs of aurantioclavine

4-Hydroxy-4,5,5-trimethyl-3-[2-(2-methyl-7-R-1H-indol-3-yl)ethyl]-1,3-oxazolidin-2-ones (R = H or Alk), which were synthesized from 4-methylidene-1,3-dioxolan-2-one and substituted 2-methyltryptamines, undergo intramolecular amidoalkylation when treated with polyphosphoric acid. First representatives of a new heterocyclic system, viz., oxazolo[3",4":1,2]azepino[5,4,3-cd]indole, which are core analogs of aurantioclavine, were prepared.     

Synthesis of [4,5-Bis(hydroxymethyl)-1,3-dioxolan-2-yl]nucleosides as Potential Inhibitors of HIV

The synthesis of 1,3-dioxolan-2-ylnucleosides and related chemistry is described. We have shown that 2-methoxy-1,3-dioxolane (6) reacts with silylated thymine and trimethylsilyl triflate to give the acyclic formate ester 1-[2-(formyloxy)ethyl]thymine (8) rather than 1-(1,3-dioxolan-2-yl)thymine (7). A tentative mechanism which could explain this result is discussed. On the other hand, 2-methoxy-1,3-dioxolane 13c reacts with silylated bases to give [4,5-bis(hydroxymethyl)-1,3-dioxolan-2-yl]nucleosides, thus representing the first examples of this novel class of compounds. The nature of the nucleobase and the hydroxyl protecting groups was found to have great influence on the reaction and on the stability of the nucleosides. Compounds 16 and 18 were found to be inactive when tested for anti HIV-1 activity in vitro.     

Preparation and polymerization of some vinyl monomers containing the 2-oxo-1,3-dioxolane group

The syntheses and polymerizations of (2-oxo-1,3-dioxolan-4-yl)methyl acrylate, 4-(2-oxo-1,3-dioxolan-4-yl)methyl itaconate, and (2-oxo-1,3-dioxolan-4-yl)methyl maleate are described. Reactivity ratios in the copolymerization of these monomers with other comonomers are reported and the Alfrey-Price Q and e values calculated. The post-polymerization effects of ultraviolet light and heat on these polymers and copolymers are presented and compared to those for similar polymers containing the 2,2-dimethyl-1,3-dixolane groups, which performs as an internal ultraviolet sensitizer. The 2-oxo derivatives are crosslinked thermally but not by ultraviolet light. The crosslinking reaction can be catalyzed by acids, bases, and salts.     

Preliminary studies on a novel synthesis of β-amino acids: stereocontrolled transformation of d- and l-glyceraldehyde into 3-amino-2-(2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)propanoic acids

A stereocontrolled synthesis of the methyl ester of (2S)-3-amino-2-((4′S)-2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)propanoic acid from d-glyceraldehyde is described for the first time. This method involves the stereoselective Michael addition of the lithium salt of tris(phenylthio)methane to (S)-2,2-dimethyl-4-((E)-2-nitrovinyl)-1,3-dioxolane followed by hydrolysis of the resulting (4S)-2,2-dimethyl-4-((2′S)-3′-nitro-1′,1′,1′-tris(phenylthio)propan-2′-yl)-1,3-dioxolane to (2S)-methyl 2-((4′S)-2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)-3-nitropropanoate, which was finally reduced to the target compound. A similarly stereocontrolled transformation of l-glyceraldehyde into (2R)-methyl 3-amino-2-((4′R)-2′,2′-dimethyl-1′,3′-dioxolan-4′-yl)propanoate is also described.     

Synthesis of <Emphasis Type="Italic">O</Emphasis>-[2-hydroxy-3-(vinyloxy)propyl]oximes and <Emphasis Type="Italic">O</Emphasis>-[(2-methyl-1,3-dioxolan-4-yl)methyl]oximes

By oximes reaction with glycidyl vinyl ether O-[2-hydroxy-3-(vinyloxy)propyl]oximes of ketones and acetaldehyde were synthesized in 54–72% yield, and by acid catalysis the compounds were converted into O-[(2-methyl-1,3-dioxolan-4-yl)methyl]oximes in 61–88% yield.     

Preparation and polymerization of some vinyl monomers containing the 1,3-dioxolane group

The synthesis and structure determinations of (2,2-dimethyl-1,3-dioxolan-4-yl)-methyl acrylate, 4-(2,2-dimethyl-1,3-dioxolan-4-yl)methyl itaconate, and [(2,2-dimethyl-1,3-dioxolan-4-yl)methyl] methyl fumarate are described. Reactivity ratios in the copolymerization of these monomers with other comonomers are reported and the Alfrey-Price Q and e values calculated. The post-polymerization study of the effects of ultraviolet light and heat on these polymers and copolymers is presented. The 1,3-dioxolane group when appended to the polymer chain performs as an internal ultraviolet sensitizer. A mechanism is offered to explain the crosslinking behavior of these polymers when treated with ultraviolet light.     

1-Oxa-3-azapentalen-2-ones as Precursors of cis-2-Amino Alcohols: Synthesis from Propargyl Alcohols, CO2, and Amines Using an Intramolecular Amidoalkylation Reaction of Oxazolidin-2-ones

The reaction of 5-methyl-5-(4-methyl-3-pentenyl)-4-methylene-1,3-dioxolan-2-one with primary amines gives the corresponding 4-hydroxy-4-methyloxazolidin-2-ones. These undergo an intramolecular amidoalkylation reaction to form 1-oxa-3-azapentalen-2-ones which are potential precursors of cyclopentanyl cis-2-amino alcohols.     

Synthesis of C-Nucleoside Analogues： 2-[2-（Hydroxymethyl）-1, 3-dioxolan-5-yl]1, 3-thiazole-4-carboxamide and 2-[2-（Mercaptometh-yl）-1, 3-dioxolan-5-yl] 1, 3-thiazole-4-carboxamide

Novel C-nucleosides of tiazofurin analogue (2-[2-(hydroxymethyl)-1,3-dioxolan-5-yl] 1,3-thiazole-4-carboxamide) and its thiol-substituted derivative (2-[2-(mercaptomethyl)-1,3-dioxolan-5-yl] 1, 3-thiazole-4-carboxamide) were synthesized from methyl acrylate through a multistep procedure. Their structures were confirmed by IR, ^1HNMR, ^13CNMR and elemental analysis.     

Piperidine-mediated synthesis of thiazolyl chalcones and their derivatives as potent antimicrobial agents

A series of new thiazolyl chalcones, 1-[2-amino-4-methyl-1,3-thiazol-5-yl]-3-aryl-prop-2-en-1-one were prepared by piperidine mediated Claisen-Schmidt condensation of thiazolyl ketone with aromatic aldehyde. These chalcones on cyclisation gave 2-amino-6-(2-amino-4-methyl-1,3-thiazol-5-yl)-4-aryl-4H-pyridine-3-carbonitrile and 2-amino-6-(2-amino-4-methyl-1,3-thiazol-5-yl)-4-aryl-4H-pyran-3-carbonitrile. The result showed that the compounds exhibited marked potency as antimicrobial agents.     

Photocrosslinking of polymethoxymethylstyrene and copolymers containing (2,2-disubstituted-1,3-dioxolan-4-yl)methoxymethylstyrene

Methoxymethylstyrene (MSt), (2,2-dimethyl-1,3-dioxolan-4-yl)methoxymethylstyrene (MMSt), and (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methoxymethylstyrene (EMSt) were synthesized and homopolymerized and copolymerized. The photochemical behavior of resultant homopolymers and copolymers with methyl methacrylate (MMA) and styrene (St) were investigated. The infrared (IR) and ultraviolet (UV) spectra of poly(MSt) showed that new bands ascribed to methyl benzoate residue increase rapidly with irrdiation time in air, but no detectable changes are observed in vacuum. The solubility measurements of poly(MSt) indicate that the main factor in crosslinking is the direct coupling of the benzyl radical generated by UV irradiation, which was confirmed by photopolymerization of MMA by means of benzyl methyl ether. It was also found that copolymers of MMSt or EMSt with MMA or St are easily crosslinked by UV irradiation. From the results of solubility measurements of these copolymers irradiated both in air and in vaccum, it was concluded that not only the 1,3-dioxolane structure but also the benzyl methyl ether structure takes part in photocrosslinking, as we expected.     

Synthesis of Some New Thiazoles and Pyrazolo[1,5-a]pyrimidines Containing an Antipyrine Moiety

Ethyl 2-{2-[4-(2,3-dimethyl-5-oxo-1-phenyl-3-(pyrazolin-4-yl)]-2-cyano-1-(phenylamino)vinylthio}-acetate, 2-[4-(2,3-dimethyl-5-oxo-1-phenyl-(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]2-(4-oxo-3-phenyl-(1,3-thiazoilidin-2-ylidene))ethanenitrile, 2-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]-2-(4-methyl-3-phenyl(1,3-thiazolin-2-ylidene))ethanenitrile, 2-(5-acetyl-4-methyl-3-phenyl(1,3-thiazolin-2-ylidene))-2-[4-(2,3-dimethyl-5-oxo-1-phenyl(3-pyrazolin-4-yl))(1,3-thiazol-2-yl)]ethanenitrile, and ethyl 2-(cyano(4-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-yl)thiazol-2-yl)methylene)-2,3-dihydro-4-methyl-3-phenylthiazole-5-carboxylate were synthesized by treatment of 2-(4-(2,3-dihydro-1,5-dimethyl-3-oxo-2-phenyl-1H-pyrazol-4-yl)thiazol-2-yl)-3-mercapto-3-(phenylamino)-acrylonitrile with appropriate halo ketones or halo esters. Also, 4-{2-[5,7-dimethyl-2-(phenylamino)(7a-hydropyrazolo[1,5-a]pyrimidin-3-yl](1,-thiazol-4-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one derivatives were synthesized via reaction of 4-{2-[5-amino-3-(phenylamino)pyrazolin-4-yl](1,3-thiazol-2-yl)}-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one with β-diketone or β-keto ester. All synthesized compound were established by elemental analysis, spectral data, and alternative synthesis whenever possible.