study, new α-indolylacrylate derivatives were synthesized by the reaction of 2-substituted indoles with various pyruvates using a Brønstedacidionicliquid catalyst in butyl acetate solvent. This is the first report on the application of pyruvate compounds for the synthesis of indolylacrylates. The acrylate derivatives could be obtained in good to excellent yields. A preliminary biological evaluation
Various kinds of ethyl pyruvate 2-(2-substituted phenyl)hydrazones (1) were subjected to Fischer indolization with acid catalysts. All the phenylhydrazones gave corresponding normal 7-substituted indoles (2). In addition, phenyl-hydrazones whose ortho-substituent is electron-donative or has a central atom with an unshared electron pair tended to give the 4- or 5-substituted indole (3), which was produced by migration of the ortho-substituent during cyclization, whereas those whose ortho-substituent is electron-attractive tended to give little or no such abnormal product. The kind of acid catalyst used had some effect on the yield ratio of products but not on the kind of products.