Sk. Shah et al., MONOCYCLIC BETA-LACTAM INHIBITORS OF HUMAN-LEUKOCYTE ELASTASE - STEREOSPECIFIC SYNTHESIS AND ACTIVITY OF 3,4-DISUBSTITUTED-2-AZETIDINONES, Bioorganic & medicinal chemistry letters, 3(11), 1993, pp. 2295-2298
The synthesis of the four stereoisomers of -ethyl-4-[(4-carboxyphenyl)
oxy]-1-[[(phenylmethyl) amino[carbonyl]-2-azetidinone (1) starting fro
m either D or L-aspartic acid is reported. The trans (3R,4R) isomer 7a
, prepared from L-aspartic acid had the most inhibitory activity again
st human leukocyte elastase (HLE). This monocyclic beta-lactam was ver
y resistant to hydrolysis and was found to be orally bioavailable in m
armosets.