Heterocyclic systems containing bridgehead nitrogen atom: Synthesis and bioactivity of thiazolo[3', 2': 2,3]<i>-as-</i>triazino[5,6<i>-b</i>]<i> </i>in doles and isomeric thiazolo[2',3':3,4]-<i>as-</i>triazino[5,6-<i>b</i>]indoles

Abstract

2,3-Dihydro-8-isopropyl-5H-<i>as</i>-triazino[5,6-<i>b</i>] indole-3-thione <b>3</b> on condensation with <i>p</i>-bromophenacyl bromide gives 3-(<i>p-</i>bromobenzoyl) methylthio-8-isopropyl<i>-</i>5<i>H-as-</i> triazino[5,6-<i>b</i>]indole hydrobromide <b>4</b> which on PPA catalysed cyclization furnishes 3-(<i>p</i>-bromophenyl)-7 -isopropylthiazolo [3', 2': 2,3]-as-triazino[5,6-<i>b</i>]<i> </i>indoles <b>9</b> and not the angular isomer, 1-(<i>p</i>-bromophenyl)-7- isopropylthiazolo[2'. 3': 3,4]-<i>as</i>-triazino [5,6-<i>b</i>]indole <b>6</b>. The unequivocal synthesis of the latter <b>6</b> has also been accomplished. The antibacterial and antifungal activity of some of the compounds have also been evaluated.