Synthesis of spiro(benzo[<i>h</i>]quinazoline-5,1′-cyclohexane) derivatives

Abstract

3-p-Methoxyphenyl-4-oxo-2-mercapto-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane) was synthesized by the reaction of 4-amino-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1'-cyclohexane) (I) with p-methoxyphenvl isothiocyanate without separation of the thioureido derivative. Amino ester I is transformed by acetamide and formamide into 2-methyl-4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane) and 4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane (II), respectively. Alkylation of quinazoline II with methyl iodide results in formation of 3-methyl-4-oxo-3,4,5,6-tetrahydrospiro (benzo[h]quinazoline-5,1′-cyclohexane). Amino ester I reacts with caprolactam with formation of 2,3-pentamethylene-4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane). 4-Ethoxymethyleneamino-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1′-cyclohexane) was synthesized by the reaction of amino ester 1 with o-formic ester, and was converted into 3-amino-4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane) (VIII) by hydrazine hydrate. Aminoquinazoline VIII is acylated by acid chlorides with formation of 3-acylamino-4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1′-cyclohexanes) and forms 3-benzylideneamino-4-oxo-3,4,5,6-tetrahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane) with benzaldehyde.

How to Cite
Markosyan, A. I.; Kuroyan, R. A.; Dilanyan, S. V.; Shirkhonyan, L. A. Chem. Heterocycl. Compd. 1996, 32, 462. [Khim. Geterotsikl. Soedin. 1996, 530.]

For this article in the English edition, see DOI https://doi.org/10.1007/BF01165913