R. A. Kuroyan

Synthesis and structure of 2-methyl-6-oxo-7,8-dihydrospiro(benzo[h]-triazolo[3,4-b]quinazoline-7,1′-cyclopentane)

The reaction of 4-amino-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1′-cyclopentane) with benzoyl isothiocyanate led to the corresponding 4-(N′-benzoylthioureido) derivative, the cyclization of which gave 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]qquinazoline-5,1′-cyclopentane). Condensation of the latter with hydrazine hydrate gave 2-hydrazino-3,4,5,6-tetrahydrospiro(benzo[h] quinazoline-5,1′-cyclopentane), which formed 6-oxo-1H-7,8-dihydrospiro(benzo[h] triazolo[3,4-b] quinazoline7,1′-cyclopentane) in reaction with orthoformice ester. Methylation of the product with methyl iodide led to its 2-methyl derivative.

Synthesis and reactions of 4-amino-3-carbethoxy-1,2-dihydrospiro(naphthalene-2,1′-cyclopentane)

Addition of benzylmagnesium chloride to cyclopentylidenecyanoacetic ester gives 1-benzyl-1-(cyanocarbethoxymethyl)cyclopentane and this can be cyclized to 4-amino-3-carbethoxy-1,2-dihydrospiro-(naphthalene-2,1′-cyclopentane). Acylation of the obtained aminoester with carboxylic acid chlorides produces the corresponding amides (which can react with an excess of benzoyl chloride). It can also react with orthoformic ester. In both cases the product can then react with hydrazine hydrate. Treatment of the same aminoester with caprolactam gives a tetrahydrospiro(benzo[h]quinazoline-5,1′-cyclopentane) derivative.

Synthesis of 2,3-disubstituted 4-oxo-3,4,5,6-tetrahydrospiro-(benzo[h]quinazoline-5,1′-cyclopentanes)

Abstract3-Substituted 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1′-cyclopentanes) were obtained by the reaction of 4-amino-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1′-cyclopentane) with methyl, phenyl, and benzyl isothiocyanates and cyclization of the obtained thioureas. Condensation of the products with various halides gave 2,3-substituted 4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1′-cyclopentanes). The reaction of 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1′-cyclopentane) with 1,2-dibromoethane and 1,3-dibromopropane led to 6-oxo-7,8-dihydrospiro(benzo[h]thiazolidino[2,3-b]quinazoline-7,1′-cyclopentane) and 7-oxo-8,9-dihydrospiro(benzo[h]-perhydrothiazino[2,3-b]quinazoline-8,1′-cyclopentane) respectively.

Synthesis of triazoles and tetrazoles condensed with spiro(benzo[h]quinazoline-5,1′-cyclohexane)

Condensation of 3-R-4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1′-cyclohexanes) with 2-ethanolamine, 3-propanolamine, and hydrazine hydrate gives the corresponding 2-ethanolamino, 2-propanolamino, and 2-hydrazino derivatives. Triazoles and tetrazoles, a- or b-condensed with benzo[h]quinazolines were obtained from 2-hydrazinobenzo[h]quinazolines depending on the presence of a substituent at position 3.

Synthesis of 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane and its reaction with dibromoalkanes

Abstract4-(N′-Benzoylthioureido)-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1′-cyclohexane), which was synthesized from 4-amino-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1′-cyclohexane) and benzoyl isothiocyanate, cyclized to give 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane). Reaction of the latter with 1,2-dibromoethane or 1,3-dibromopropane gave products of intramolecular dialkylation at the S and N(3) atoms.

Synthesis and structure of diethyl 2-oxo-1-oxaspiro[4,5]decane-3,4-dicarboxylate

Ethyl 1-oxaspiro[2,5]octane-2-carboxylate reacts with diethyl sodiomalonate in toluene to give diethyl 2-oxo-1-oxaspiro[4,5]decane-3,4-dicarboxylate, which on distillation under goes partial de-ethoxycarbonylation to give ethyl 2-oxo-1-oxaspiro[4,5]decane-4-carboxylate.