Nj. Westwood et al., STUDIES ON THE REACTIVITY OF AZETIDIN-2-ONES IN PHOSPHATE BUFFER, Journal of the Chemical Society. Perkin transactions. I, (18), 1997, pp. 2725-2729
H-1 NMP (500 MHz) analyses repeal that in phosphate buffer, N-arylsulf
onyl beta-lactams such as ethyl -nitrophenylsulfonyl)-2-oxoazetidine-4
-carboxylate and (4S)-ethyl -nitrophenylsulfonyl)-2-oxoazetidine-4-car
boxylate undergo hydrolysis through (minimally) two mechanisms: via di
rect hydrolysis and via an unstable acyl phosphate intermediate, The a
cyl phosphate intermediates can be trapped using hydrazine.