Condensed heterocyclic systems containing bridgehead nitrogen atom:Synthesis and bioactivity of imidazo[2,1<i>-b</i>]-1,3,4-thiadiazolo[2,3-<i>c</i>]-<i>s</i>-triazoles, <i>s-</i>triazolo-[3,4<i>-b</i>]-1 ,3,4-thiadiazolo[3,2-<i>b</i>]imidazo[4,5<i>-b</i>]<i> </i>quinoxaline and bis(<i>s</i>-triazolo[3,4-<i>b</i>]-1 ,3,4-thiadiazolo[3,2-<i>b</i>] [imidazo[4,5<i>-b</i>]cyclohexane]-5a,6a-diene)

Abstract

Condensation of 4-amino-5-mercapto-3-(<i>m</i>-methylphenyl)-<i>s</i>-triazole <b>1</b> with cyanogen bromide gives 6-amino-3-(<i>m</i>-methylphenyl)-<i>s</i>-triazolo[3,4-<i>b</i>]-1,3,4-thiadiazole <b>2</b> which on condensation with chloranil yields 3,9-di (<i>m</i>-methylphenyl)-6,14-dioxo-<i>bis</i>-(<i>s</i>-triazolo[3,4-<i>b</i> ]- 1,3,4-thiadiazolo[3,2-<i>b</i>][imidazo[4,5-<i>b</i>] cyclohexane]-5a, 6a-diene) <b>3</b>. 3-(<i>m</i>-methylphenyl)-<i>s</i>-triazolo[3,4-<i>b</i>]-1,3,4-thiadiazolo[3,2-<i>b</i>] imidazo[4,5-<i>b</i>]quinoxaline <b>4</b> is obtained by a similar condensation of <b>2</b> with 2,3-dichloroquinoxaline. The reaction of <b>2</b> with α-haloketones followed by bromination affords 7-aryl-3-(<i>m</i>-methylphenyl) imidazo[2,1<i>-b</i>]-1,3,4-thiadiazolo[2,3-<i>c</i>]-<i>s</i>-triazoles <b>5</b> and their 6-bromo analogues <b>6</b> respectively. The antibacterial and antifungal activities of some of the compounds have also been evaluated.