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.