Reactions with 4,5-diphenyl 2-mercaptoimidazole: synthesis of 2-substituted thiazolo [3,2-a] imidazoles

ABSTRACT

The potassium salt of 4,5-diphenyl-2-mercaptoimidazole [I] was reacted with 3-chloro-2,4-pentaneaione to give the S-alkyl derivative II. Compound II coupled with arenediazonium salts to give the azo derivatives [III]. On heating II and III with poly-phosphoric acid, cyclization took place and 2-substituted thiazolo [3,2-a] imidazoles V and VI were obtained. V Condensed with aromatic aldehydes to yield the cinnamoyl derivatives VII, which reacted with phenylhydrazine and hydroxylamine to give 2-pyr-azolinyl-and 2-isoxazolinyl-thiazolo [3,2-a] imidazole derivatives IX and X respectively