Synthesis of 2-carbethoxy-3-methyl-4-hydroxybenzofuran derivatives

A number of 2-.carbethoxy-3-methylbenzofuran derivatives were synthesized. A 5,5-gem-dibromo derivative was obtained in the bromination of 2-carbethoxy-3-methyl-4-oxo-4, 5,6,7,tetrahydrobenzofuran. Dehydrobromination of this, dibromo derivative gave 2-carbethoxy-3-methyl-4-hydroxy-5-bromobenzofuran. Depending on the structure of the starting compound and the brominating agent, the bromine in the bromination of 2-carbethoxy-3-methyl-4-hydroxy- and 4-acetoxybenzofurans with bromine and N-bromosuccinimide is incorporated either in the methyl group or in 5 and 7 positions of the benzofuran ring. The nitration of 2-carbethoxy-3-methyl-4-hydroxybenzofuran and its bromo derivative leads to 5-nitro- and 5,7-dinitrobenzofuran derivatives. The structures of the synthesized benzofuran derivatives were established by means of the PMR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 27–29, January, 1980.     

Azo coupling and aminomethylation of 2,5-diphenylpyrrole and its derivatives

The azo coupling of 2,5-diphenylpyrrole with arenediazonium chlorides has given previously unknown 3-arylazopyrroles and 4-phenylazo-3-phenylhydrazono-3H-pyrrole. The methylation and reductive acetylation of the anylazo derivatives have led to N-methylarylazo and acetylamino derivatives of 2,5-diphenylpyrrole. 3-Amino-2, 5-diphenylpyrrole has been obtained by the reduction of 3-p-chlorophenylazo-2,5-diphenylpyrrole. The aminomethylation of 2,5-diphenylpyrrole and its derivatives with bis(dialkylamino)methanes had led to aminomethyl derivatives.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5. pp. 612–615, May, 1986.     

Formylation of 2-phenyl- and 3-phenyl-5-hydroxybenzofuran derivatives

The Vilsmeier formylation of 2-phenyl- and 3-phenyl-5-hydroxybenzofuran derivatives was studied. It is shown that 2-phenyl-5-methoxybenzofuran is formylated in the 4 position, whereas 3-phenyl-5-methoxybenzofuran is formylated in the 2 position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1023–1024, August, 1976.     

Functional derivatives of thiophenes

2,3-Polymethylene-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine derivatives were obtained by reaction of esters of α-aminothiophene-β-carboxylic acids with lactame or α-aminothiophene-Β-carboxylic acids with lactims. Desulfuration of the thienopyrimidines obtained in this manner is a convenient method for the synthesis of pyrrolo-, pyrido-, and azepino[1,2-a]pyrimidine derivatives.     

Functional derivatives of thiophene

A method is proposed for the synthesis of isatin analogs — 4,5-dioxothieno[2,3-b] pyrroles and 5,6-dioxothieno[3,2-b]pyrroles — by reaction of oxalyl chloride with amino-substituted α-amino- and Β-aminothiophene. The thiosemicarbazones of 4-ary1-5,6-dioxothieno[3,2-b]pyrroles were synthesized. n]mis|See [1] for communication X.     

Synthesis of aminoalkyl derivatives of 2-benzyl-5-hydroxyindole

Derivatives of 2-benzyl-5-methoxyindole-3-carboxylic acid are decarboxylated on heating and are converted to the corresponding 2-benzyl-5-methoxyindoles. 2-Benzyl-5-methoxygramine hydrochlorides were obtained from the latter and used to obtain (2-benzyl-5-methoxy-3-indolyl)acetonitriles. The nitriles were converted to 2-benzyl-5-methoxytryptamines by hydrogenation. A number of Mannich bases were obtained by aminomethylation of 2-benzyl-3-carbomethoxy-5-hydroxyindole derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 208–212, February, 1971.     

Functional derivatives of thiophene. XV.β-Thienylhydrazine derivatives in the synthesis of thieno[3,2-b]pyrroles

A new preparative method for the synthesis of thieno[3,2-b]pyrrole derivatives by condensation of ß-thienylhydrazine derivatives with diverse carbonyl compounds under the conditions of the Fischer reaction is described.     

Vilsmeier formylation of 2-methyl-3 -carbethoxy-5-methoxy- and 2-methyl-5-methoxyindoles

The corresponding 6- and 3-formyl derivatives were obtained by formylation of 2-methyl-3-carbethoxy-5-methoxy- and 2-methyl-5-methoxyindole derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 339–341, March, 1971.     

Protonation of pyrrolo [1,2-α] Pyrimidine derivatives

The protonation of pyrrolo [1,2-] pyrimidine and 6, 7, 8, 9-tetrahydropyrimido [1, 2-] indole derivatives in CF₃COOH (at –15 to +25° C) and in CF₃COOH/H₂SO₄ (at 25°) was studied by PMR spectroscopy. The investigated compounds form monocations, the structure of which corresponds to the addition of a proton to the carbon atom of th pyrrole fragment in the position to the bridge nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 686–692, May, 1976.     

Functional derivatives of thiophene

2-Aryl-4-oxothieno[2,3-d]oxazine derivatives were synthesized. Opening of the oxazine ring to give 2-benzamidothiophene-3-carboxylic acid hydrazide derivatives is observed when these compounds are treated with hydrazine hydrate.See [1] for Communication 17.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 45–46, January, 1980.