Acylation products of N-acyllactams and their activation effect in the anionic polymerization of lactams

Benzoylation of metalated N-benzoyllactams, derived from 7-, 9- and 13-membered lactams, gives rise to both N-benzoylenol esters ( 1 ) and N,2-dibenzoyllactams ( 3 ), whereas in the case of derivatives of 5- and 6-membered lactams only products 3 by C-acylation in position 2 were isolated. In the propionylation of N-benzoyl- or N-propionyl-6-hexanelactam, only products of O-acylation were formed. The aminolysis of 3 gave rise to 2-benzoyllactams ( 4 ). For selected compounds of type 1–4 the activation effect in the anionic polymerization of 6-hexanelactam was found to be comparable with that of N-acyllactams. The equilibrium acidities in DMSO were measured for 3 and 4 .