ALPHA-AMINOSULFONOPEPTIDES AS POSSIBLE FUNCTIONAL ANALOGS OF PENICILLIN - EVIDENCE FOR THEIR EXTREME INSTABILITY

Sulfonopeptide analogs of acyl-D-Ala-D-Ala bearing an alpha-aminosulfo nic acid moiety in the penultimate position have been synthesized usin g a Curtius rearrangement step. The sulfonopeptides were prepared and examined in aprotic solvents, but they proved to be exceedingly labile in protic solvents: for example, alpha-acylaminosulfonodipeptide 31 p roved to be too unstable to isolate in pure form and its methyl ester, 34, decomposed with a half-life of ca. 8 min in 50% methanol at pD=5 and at 25 degrees C. A mechanistic study relating to the stability of the alpha-sulfonopeptides is delineated, including an analysis of the decomposition products in aqueous solution. Copyright (C) 1996 Elsevie r Science Ltd