Condensed bridgehead nitrogen heterocyclic systems:Synthesis and antimicrobial activity of thiazolo[3', 2': 2, 3]-<i>as</i>-triazino[5,6<i>-b</i>]indoles and isomeric thiazolo[2', 3': 3,4]-<i>as</i>-triazino[5, 6-<i>b</i>]indoles

Abstract

2, 3-Dihydro-6-ethyl-5<i>H</i>-<i>as</i>-triazino[5, 6-<i>b</i>]indole-3-thione <b>4</b> on condensation with α-haloketone gives 3-aroylmethylthio-6-ethyl-5<i>H</i>-<i>as</i>-triazino[5, 6-<i>b</i>]indolehydrobromide <b>5</b> which on PPA catalyzed cyclization furnishes 3-aryl-9-ethylthiazalo[3', 2': 2, 3]-as-triazino[5, 6-<i>b</i>]indole <b>6</b> and not the isomer, 1-aryl-9-ethylthiazalo[2', 3': 3,4]-<i>as</i>-triazino[5, 6-<i>b</i>]indole <b>8</b>. The unequivocal synthesis of <b>8</b> has also been accomplished. The antibacterial and antifungal activity of the compound <b>6</b> has also been evaluated.

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