Photodecarboxylation of N-Phthaloyl-α-amino Acids

Abstract

N-Phthaloylglycine (1a) was irradiated with a high pressure mercury lamp to give N-methylphthalimide (2a) in an excellent yield. N-Phthaloyl derivatives 1b-k of other α-amino acids also afforded the decarboxylated products 2b-k. In the cases of N-phthaloylserine (1l) and di-phthaloylcystine (1m), N-vinylphthalimide (3) was isolated as a major product. On the other hand, N-phthaloylmethionine (11a) and methyl N-phthaloylmethionate (11b) were treated in the same manner to give the aza-thiacycloheptanol derivatives 12a-b having a new ring system. Solvent effects and possible pathways of these reactions were examined.