Heterocyclic systems containing bridgehead nitrogen atom: Synthesis and antimicrobial activity of spiro[cycloalkane-1', 7(8<i>H</i>)-(6<i>H</i>)-<i>trans</i>-3,<i> </i>3a-dihydropyrazolo[3', 4':4,5] thiazolo[3, 2-<i>b</i>]-<i>s</i>-tetrazines]

Abstract

A facile synthesis of trans-3, 3<i>a</i>-dihydro-3-arylspiro[cycloalkane-1', 7(8<i>H</i>)[6<i>H</i>]pyrazolo[3', 4':4, 5]thiazolo[3, 2-<i>b</i>]-<i>s-</i>tetrazines <b>3</b> has been achieved by the condensation of 1, 2, 4, 5-tetraazaspiro[5, 7]tridecane-3-thione <b>1a</b> or 1, 2, 4, 5-tetraazaspiro [5, 6] dodecane-3-thione <b>1b</b> or 1, 2, 4, 5-tetraazaspiro[5, 5]undecane-3-thione <b>1c</b> with ethyl chloroacetate and aldehydes in the presence of pyridine and piperidine to yield 7-arylidene-6(7<i>H</i>)-oxospiro[cyclooctane/ cycloheptane/ cyclohexane]-1, 3 (4<i>H</i>)-[2<i>H</i>]<i> </i>thiazolo [3, 2-<i>b</i>]-<i>s</i>-tetrazines <b>2</b> followed by treatment with <i>p</i>-nitrophenylhydrazine. The antibacterial and antifungal activity of some of the compounds have also been evaluated.