A ready synthesis of some N-substituted 3-alkoxycarbonyl-2-pyrrolinones

The synthetic methods for the preparation of pyrrolopyrimidines have been recently reviewed and since that report an increasing number of papers have dealt with the chemistry of these heterocyclic systems for their structural resemblance to purines, natural occurrence and biological significance. Good examples of this are k4 the pyrrolo [2,3-d] pyrimidine nucleosides Q and Q. Among others, 3-alkoxycarbonyl-2-pyrrolinones 2 can be useful intermediates for the preparation of pyrrolo [2,3-d] pyrimidines? However, it appears from the literature that for the preparation of compounds which belong to class g few methods have been described, all preparing the 2-pyrrolinone system by cyclization of a suit able intermediate? The direct functionalization of the carbon 3 of 2-pyrrolinones has not been exploited yet, althogh few examples of related systems have 6 been realized. On the other hand, it has bFen shown that the aldol condensation of 2-pyrrolinone with aromatic aldehydes proceeds at position 3 when a strong electron 7 withdrawing group is attached to the lactamic nitrogen. In this case, the acidity of the hydrogens a to the carbony1 is enhanced, although yields are lmered by competitive condensation at the N-protecting group, if this 8 is an acetyl moiety.