SYNTHESIS OF SUBSTITUTED INDOLYLTHIADIAZOLINES AND INDOLYLISOXAZOLINES

Abstract

Thiosemicarbazides (2a-d) are prepared by the reaction of substituted 2-phenyl-3-aminoindoles (1a-d) with ammonia and carbon disulphide in ethanol, followed by addition of sodium chloroacetate and hydrazine hydrate. These carbazides (2a-d) are reacted with various araldehydes in boiling ethanol using catalytic amount of gl. acetic acid to get araldehyde 4-(substituted indole-3-yl)-3-thiosemicarbazones (3a-l). Compounds 3a-l when treated with NaOH (5%) and potassium ferricyanide solution furnish the indolyliminothiadiazolines (4a-l). 2-Phenyl-3-chalcones (6a-d) are prepared by reacting 2-phenylindole-3-carboxaldehydes (5a-c) with acetophenones. The chalcones (6a-d) on treatment with hydroxylamine hydrochloride in ethanolic NaOH afford 3-phenyl-5-(substituted indole-3-yl)isoxazolines (7a-d) in good yields.