Synthesis of new liquid-crystalline compounds from the 3-aryl-5-alkylpyrazole series

A method was developed for the preparation of new liquid-crystalline substances, pyrazole derivatives, through the corresponding 2-isoxazolines and isoxazoles. The hydrogenolysis of the heterocycle in 3-(4-hydroxyphenyl)-5-amylisoxazole afforded 1-amino-1-(4-hydroxyphenyl)-1-octen-3-one. The acid hydrolysis of the compound followed by treating with hydrazine hydrate resulted in 5-amyl-3-(4-hydroxyphenyl)-1H-pyrazole, whose benzylation and esterification with the corresponding mesogenous benzyl chlorides and benzoyl chlorides provided liquid-crystalline 5-alkyl-3-aryl-1H-pyrazoles.     

5-烃基-5-对甲苯磺酰氧基丙二酸亚异丙酯的合成

报道了利用羟基(对甲苯磺酰氧基)碘苯与5-烃基丙二酸亚异丙酯的反应合成5-烃基-5-对甲苯磺酰氧基丙二酸亚异丙酯的方法。提出了该反应的可能机理。     

Synthesis and properties of 2-alkyl-5-ethynyltetrazoles

2-Alkyl-5-ethynyltetrazoles were synthesized. It is shown that ethynyltetrazoles have a triple bond with increased electrophilicity. They readily add aliphatic alcohols and amines and undergo aminomethylation, the Iotsich reaction, oxidative dimerization, and the cycloaddition of azides. 1-Phenyl-3-tetrazolyl-2-propyne, which has the properties of α-acetylenic ketones, was obtained by selective oxidation of tetrazolylethynylcarbinol. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 842–847, June, 1980.     

Synthesis of 4-methyl-5-alkyl-2-imidazolinones

Conclusions 4-Methyl-5-alkyl-2-imidazolinones were synthesized by heating 3-halo-2-alkanones with a mixture of piperidine, N,N-diethylacetamide, urea, zinc chloride and magnesium carbonate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1887–1890, August, 1987.     

Synthesis of 1-alkyl-2-nitroimidazole-5-carboxaldehydes

We report the preparation of 1-methyl- and 1-ethyl-2-nitroimidazole-5-carboxaldehydes (Ia,b). For Ia three different routes of synthesis are described, which appear of general value for preparing 1-alkyl substituted 2-nitroimidazole-5-carboxaldehydes.     

Synthesis and nucleophilic substitutions of 3-alkyl-5-chloroisoxazoles

A 3-alkyl-5-chloroisoxazole synthesis is described based on the cycloaddition of nitrile oxides to 1,1-dichloroethylene, an inexpensive dipolarophile. Substitution of the chloride in these adducts by various nucleophiles is also described.     

Synthesis of 5-alkyl-1,3,5-triazinan-2-ones and 5-alkyl-1,3,5-triazinane-2-thiones using Cu- and Sm-containing catalysts

Efficient procedures have been developed for the synthesis of 5-alkyl-1,3,5-triazinan-2-ones and 5-alkyl-1,3,5-triazinane-2-thiones by reaction of urea (thiourea) with primary alkylamines and N,N,N′,N′-tetramethylmethylenediamine and by reaction of primary amines with N,N′-bis(dimethylaminomethyl)urea(thiourea) in the presence of Cu- and Sm-containing catalysts.     

Synthesis of bis-3-alkyl-5-arylhydantoins and bis-3-alkyl-5-arylthiohydantoins separated by two and four carbon atoms

Synthesis of 1,2- and 1,4-bis-thiohydantoins and hydantoins employing ethylenediamine and 1,4-diaminobutane as spacers is described. Compounds containing a two carbon bridge were synthesized by alkylation of ethylenediamine with two equivalents of N-t-butyl-α-(p-toluenesulfonyloxy)phenylacetamide 3 . The phenyl isothiocyanate adduct of 3 cyclized in refluxing toluene to form 1a . Other isothiocyanate or isocyanate adducts derived from alkylation product 4 required hydrolysis to induce cyclization. Compounds 1b-1f were obtained in this way. Compounds with a four carbon bridge were obtained by reaction of two equivalents of methyl α-bromophenyl acetate and 1,4-diaminobutane to produce N,N'-bis-[(α-phenyl-α-methoxycarbonyl)methyl]butylenediamine 6 . The isothiocyanate or isocyanate adducts from 6 cyclized, without hydrolysis, to form compounds 2a-2e .     

Synthesis of 5-alkyl-3H-thiolen-2-ones and 5-alkyl-3H-furan-2-ones and condensation reactions at the heterocyclic methylene group

The intramolecular cyclization of -ketocarboxylic acids and their esters gives 5-alkylsubstituted 3H-thiolen-2-ones and 3H-furan-2-ones. It was shown that reaction occurred at the heterocyclic methylene group and that the conditions under which the reaction took place depended on the nature of the heterocyclic atom.Translated from Khimiya Geterotsiklicheskikh Soedinnenii, No. 4, pp. 451–454, April, 1987.     

Synthesis of 1-alkyl-4(5)-hydroxymethyl-1,2,3-triazoles

An in situ method for the synthesis of 1-alkyl-4(5)-hydroxymethyl-1,2,3-triazoles by the action of acetylenic alcohols with alkyl azides as the latter are formed from sodium azide and alkyl halides in dimethylformamide is proposed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1688–1689, December, 1980.     

Synthesis of mesomorphic 2-alkyl-5-(p-cyanophenyl)pyridines

A new series of liquid-crystal derivatives of 2-alkyl-5-(p-cyanophenyl)pyridines were obtained by halogenation of 2-alkyl-5-phenylpyridines under the conditions of the Birckenbach-Gubo-Waters reaction with subsequent conversion of the 2-alkyl-5-(p-bromo- or iodophenyl) pyridines to the cyano derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 85–88, January, 1981.     

Synthesis of 4-alkyl-3-pyridinols from 3-benzyloxypyridine

The addition of Grignard reagents to the 1-phenoxycarbonyl salt of 3-benzyloxypyridine and a catalytic amount of cuprous iodide afforded 4-alkyl-3-benzyloxy-1-phenoxycarbonyl-1,4-dihydropyridines in good yield. The crude dihydropyridines were aromatized with o-chloranil to give 4-alkyl-3-benzyloxypyridines, which were debenzylated with hydrogen and 10% palladium on carbon to provide 4-alkyl-3-pyridinols.     

Synthesis of 1-alkyl-5-phenyl-4(1H)pyrimidinones

1-Alkyl-5-phenyl-4(1H)pyrimidinones are readily synthesized by condensing β-(dimethylamino)-N-[(dimethylamino)methylene] atropamides with methyl or ethyl amine. The latter compounds are prepared from phenylacetamides and dimethylformamide dimethyl acetal.