The formation of lactams from L-ascorbic acid

2,3-O-Dimethyl-6-O-p-toluenesulphonyl-L-ascorbic acid reacted with the primary amines n-butylamine, benzylamine and cyclohexylamine at room temperature to give the 1-alkyl-2,3-dimethoxy-4-hydroxy-4-[1'-(2'-aminoalkyl)ethyl]but-3-enimides in 64, 58 and 60% yields, respectively, after chromatographic purification. However, 2,3-O-dimethyl-5,6-di-O-p-toluenesulphonyl-L-ascorbic acid reacted with n-butylamine, benzylamine and cyclohexylamine to give the 1-alkyl-2,3-dimethoxy-4-hydroxy-4-[1'-(2'-aminoalkyl)ethyl]but-3-enimides in 61, 74 and 75% yields, respectively. The absolute configuration for one of the products was established by X-ray crystallography. (C) 1999 Elsevier Science Ltd. All rights reserved.