Studies on the Design and Synthesis of New Monocyclic β-Lactams Containing Substructures of Penicillin G

Abstract

The studies on design and synthesis of new monocyclic β-lactam esters 4(R/S)-(1'-methoxycarbonylpropyl-2'(R/S)-thio)-3(R)-phenylacetamidoazetidin-2-one (3a) and 4(R/S)-(1'-methoxycarbonyl-2'-methyl-propyl-2'-thio)-3(R)-phenylacetamidoazetidin-2-one (3b) were described. Compounds 3a and 3b were specifically designed to retain all penicillin substructures except the bicyclic system, which would be conceived by cleaving the C(3)-N(4) bond of penicillin G. Compounds 3a and 3b are of particular interest in the context of the structural elucidation of monocyclic β-lactams originated from penicillin. Key intermediates, β-mercapto esters 6a and 6b, were synthesized from conjugate acids 4a and 4b using three-step synthetic sequences, respectively, and 4(S)-acetoxy-3(S)-phenylacetamidoazetidin-2-one (7) was obtained from the degradation of penicillin G. Reactions of 6a and 6b with 7, thus obtained, provided the target compounds 3a and 3b, respectively.

Copper(i)-catalyzed radical carboamination reaction of 8-aminoquinoline-oriented buteneamides with chloroform: synthesis of-β-lactams

“…Nitrogen-containing heterocycles are notable compounds known for their bioactivity in nature. 1 In particular, functionalized β-lactams are the core skeleton of many natural products and antibiotics drug molecules with specific effects, such as penicillins, 2 carbapenems, 3 cephalosporins 4 and monocyclic β-lactams 5 ( Fig. 1 ).…”