Rahil J1, Pratt RF.
Biochemistry. 1993 Oct 12;32(40):10763-72.Four phosphonamidates were synthesized as potential beta-lactamase inhibitors. Three were methanephosphonamidates [CH3PO2-NHR/Ar, where R/Ar = 4-methoxybenzyl (3a), phenyl (3b), and m-nitrophenyl (3c)], while the fourth, PhCH2OCONHCH2PO2-NHPh (2a), also contained a beta-lactamase active site-directed amido side chain. The pH-rate profiles for the hydrolyses of these compounds in the absence of enzyme demonstrated the necessity of nitrogen protonation in the transition state; the reactive neutral form was the zwitterion, IH. Read More