Synthesis of some substituted 3-alkenyl-1-phenylpyrazoles

The regioselective synthesis of new 3-alkenyl-1-phenylpyrazoles 4 from the reaction of phenylhydrazine with 2,3-dihydro-4H-pyran-4-ones 1 is described.     

Synthesis and some transformations of 2,6-diphenyl-4-hydroxybenzofuran

A 4-oxotetrahydrobenzofuran derivative was obtained from 5-phenylcyclohexane-1,3-dione and phenacyl bromide, and dehydrogenation of the latter gave 2,6-diphenyl-4-hydroxybenzofuran. Some reactions of 2,6-diphenyl-4-hydroxybenzofuran and its derivatives were studied.     

Synthesis of some 3-alkenyl-4-oxo-6,7-dihydro-4H-pyrano[3,4-d]isoxazoles

A series of 3-alkenyl-4-oxo-6,7-dihydro-4H-pyrano[3,4-d]isoxazole derivatives was prepared by reaction of hydroxylamine with 4,5-dioxo-2,3,7,8-tetrahydro-4H,5H-pyrano[4,3-b]pyran derivatives.     

Synthesis and pharmacological effect of some 5-alkyl and 5-alkenyl-4-hydroxyisophthalic acids and esters

The synthesis of some 5-alkyl- and 5-alkenyl-4-hydroxy (resp. acyloxy- resp. alkoxy)-isophthalic acids and esters is described. Some of the described derivatives exhibit analgetic, antipyretic and antiphlogistic activity.     

Synthesis and some transformations of 1, 2, 3, 4-tetrahydrophenothiazine derivatives

1,2,3,4-Tetrahydrophenothiazine derivatives were obtained from cyclic monoketones and 1,3-diketones and o-nitroarenesulfenyl chlorides. The alkylation, aminomethylation, and oxidation of the compounds obtained were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1509–1513, November, 1972.     

Synthesis and some transformations of 6(8)-substituted 4-hydrazino-2-methylquinolines

6(8)-Substituted 4-hydrazino-2-methylquinolines were synthesized by reaction of the corresponding 4-chloro-2-methylquinolines with hydrazine hydrate. Reactions of the title compounds with ethyl acetoacetate and acetone gave 2,4-dimethyl-1H-pyrrolo[3,2-c]quinolines and 4-(5-ethoxy-3-methyl-1H-pyrazol-1-yl)-2-methylquinolines.     

Synthesis and some transformations of 2-acylmethyl-1,3-oxathiolanes

2-Acylmethyl-1,3-oxathiolanes, which form oximes with hydroxylamine and perchlorates with perchloric acid, were synthesized by reaction of -alkynyl ketones with ß-mercaptoethanol.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1041–1043, August, 1978.     

Synthesis of 4-acyl-and 235 4-alkenyl-3,5-dimethylisothiazole derivatives

4-Acyl- and 4-alkenyl-3,5-dimethylisothiazole derivatives, not available by direct electrophilic substitution [1–5] have been prepared from 3,5-dimethyl-4-isothiazolylcarbonitrile 1 and the corresponding aldehyde 2 in satisfactory yields. Both compounds, 1 and 2 , are readily obtained from 3,5-dimethyl-4-iodoisothiazole, whose preparation we have previously reported [6].     

2-perfluoroalkanoylcyclopentane-1,3-diones. Synthesis and some transformations

2-Perfluoroalkanoylcyclopentane-1,3-diones were synthesized for the first time by acylation of cyclopentane-1,3-dione with perfluorocarboxylic acids in the presence of 1,1??-carbonyldiimidazole or with perfluorocarboxylic anhydrides in the presence of imidazole. 2-Perfluoroalkanoylcyclopentane-1,3-diones were selectively reduced to 2-(1-hydroxyperfluoroalkyl)cyclopentane-1,3-diones by the action of triethylsilane in trifluoroacetic acid in the presence of a catalytic amount of lithium perchlorate. Treatment of the title compounds with oxalyl chloride and subsequent reaction with 2 equiv of primary amine (4-fluoroaniline, 4-fluorobenzylamine, 3,4-difluoroaniline, 3-trifluoromethylbenzylamine) gave the corresponding 3-arylamino-2-perfluoroalkanoylcyclopent-2-en-1-ones.     

Synthesis and transformations of 4-substituted 2-aminothiazoles

4-Substituted 2-aminothiazoles were synthesized and some of the transformations of these compounds at the amino group were studied. A number of new thiazole derivatives were obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 715–718, May, 1993.     

Synthesis of 2-imino-4-vinyl-2,5-dihydrofuran-3-carboxamides and some their chemical transformations

2-Imino-2,5-dihydrofuran-3-carboxamides containing 2-phenyl- and 2-furylvinyl substituents in position 4 of the furan ring were synthesized by condensation of 2-imino-4-methyl-2,5-dihydrofuran-3-carboxamides with the corresponding aldehydes. Acid hydrolysis of 4-(2-arylvinyl)-2-imino-2,5-dihydrofuran-3-carboxamides gave 4-(2-arylvinyl)-2-oxo-2,5-dihydrofuran-3-carboxamides, and their condensation with malononitrile resulted in the formation of 2-dicyanomethylidene derivatives.     

Synthesis and some transformations of functionally-substituted coumarins and 2-thioxo-2H-chromenes

A synthesis has been developed for substituted coumarins and 2-thioxo-2H-chromenes and some of the chemical transformations of these compounds were studied.Yerevan State University, 375049 Yerevan, Armenia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 909–912, July, 1996. Original article submitted December 30, 1995; revision submitted April 16, 1996.     

Synthesis of 2-alkenyl-4H-anthra[1,2-b]pyran-4,7,12-triones

A method has been developed for the synthesis of 2-alkenylanthra[1,2-b]pyran-4,7,12-triones by the addition of piperidine at the triple bond of 2-alkeynoyl-1-hydroxyanthraquinones with subsequent cyclization of the adducts formed on silica gel.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1656–1659, July, 1991.     

Synthesis and some transformations of 4-aryl-substituted amines of the tetrahydropyran series

The reaction of 2-isopropyltetrahydropyran-4-one [obtained by isomerization and hydration of 3-isopropylpent-1-en-4-yn-3-ol in the presence of 5% sulfuric acid and mercury(II) sulfate] with ethyl cyanoacetate gave ethyl cyano(2-isopropyltetrahydropyran-4-ylidene)acetate which was treated with 4-tolylmagnesium chloride. The resulting ethyl cyano[2-isopropyl-4-(4-tolyl)tetrahydropyran-4-yl]acetate was subjected to decarbethoxylation to obtain 2-isopropyl-4-(4-tolyl)tetrahydropyran-4-ylacetonitrile. The latter was reduced to the corresponding amine with lithium tetrahydridoaluminate, and the reduction product was brought into condensation with aromatic aldehydes. The Schiff bases thus formed were reduced with sodium tetrahydridoborate, followed by N-acylation with acetyl and propionyl chlorides.     

Synthesis and some transformations of 4H-pyrano[3,2-d]pyrazoles

The ability of the amide carbonyl group of the pyrazolone ring to participate in the heterocyclization of oxopropyl-5-pyrazolones under the influence of polyphosphoric acid (PPA) or phosphorus polysulfide in dioxane with the formation of 4H-pyrano[ 3,2-d]pyrazole derivatives is demonstrated. Ionic hydrogenation of the pyranopyrazoles leads to 5,6-dihydropyrano[3,2-d]pyrazoles, while the action of phosphorus polysulfide in xylene leads to pyrazolo[5,4-b]thiapyrylium salts.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 317–320, March, 1982.     

Stereocontrolled synthesis of 2-alkenyl-4-methylene tetrahydropyrans

A variety of 2-alkenyl-4-methylene tetrahydropyrans were synthesized via consecutive transition metal-catalyzed bond forming processes. In this approach, ruthenium-catalyzed coupling of homoallylic carbonates and homopropargylic alcohols generates substrates containing the requisite functionality for a palladium-mediated cyclization, thereby providing concise access to the target structures. The installation of a trisubstituted alkene at the C-2 position was achieved using an olefin cross metathesis process.     

Synthesis and some transformations of dimethyl anabasylethynephosphonate

A new phosphorylated ynamine, dimethyl anabasylethynephosphonate, was synthesized by reaction of dimethyl chloroacetylenephosphonate with anabasine. Anabasylethynephosphonate obtained was shown to react under mild conditions with primary aromatic amines like p-chloroaniline, p-anisidine, and p-aminoacetophenone, whose pK _b values are in the range of 9–13, to form new asymmetrical phosphorylated acetamidines in high yields. Structure of the compounds obtained was proved by ¹H, ¹³C, and ³¹P NMR spectroscopy.