UNUSUAL TRANSFORMATION OF THE 3-HYDROXY-PICOLINOYL RESIDUE OF PRISTINAMYCIN I-A

Pristinamycin I-A was modified in a two-step procedure to give origina l derivatives possessing a tricyclic nucleus (8a, 8b, 8c) or a substit uted pyrrole ring (10a, 10b) in place of the natural exocyclic 3-hydro xy-picolinoyl residue. This transformation involved firstly preparatio n of pyridinium betaines 5 from pristinamycin I-A and secondly a 1 sim ilar to 3 dipolar cycloaddition between 5 and N-substituted maleimides or diethyl acetylenedicarboxylate. The compounds obtained were evalua ted as antibacterial agents alone and in association with pristinamyci n IIA.