A New Synthesis of β-Lactams

β-Lactam Antibiotics: Their Physicochemical Properties and Biological Activities in Relation to Structure

“…Because of the inherent acid stability and staphylococcal p-lactamase-resistant character of the cephalosporin nucleus, the semisynthetic cephalosporins have received considerable attention in the search for the ideal antibiotic. X-ray analysis has shown that, stereochemically, the p-lactam rings of penicillin and cephalosporin are essentially identical (21,179) but the exocyclic carboxyl groups are different (180). Fundamental Structural Requirements-The antibacterial activity of the P-lactam antibiotics is no doubt related directly to the fused P-lactam-thiazolidine ring (penicillin nucleus) or fused P-lactam-dihydrothiazine ring (cephalosporin nucleus), since a breakage at any point leads to complete loss of activity, irrespective of the side chain (3,8).…”

“…Sheehan and his colleagues achieved the p-lactam synthesis (21,22), which led to the formation of 5phenylpenicillin (23,24) and the sulfonyl analog of benzylpenicillin (25). This group also succeeded in the total synthesis of penicillin V (26,27) and other penicillins (28).…”

Recent Approaches Toward Solid Phase Synthesis of β-Lactams

“…One methodology involving a tributylstannane-mediated ring closure has been reported [61]. In a simple sense, the C-C bond construction (C 3 -C 4 ) involves the formation of a nucleophilic center at C 3 and an electrophilic center at C 4 , or vice versa [62]. The biosynthetic route to b-lactam has been focused primarily on the C 4 -N 1 bond formation [63].…”

Synthese von 2,2a,3,4‐Tetrahydro‐azeto[1,2‐d]benz[b]‐1,4‐oxazin‐2,4‐dionen

“…%) = 297 (2,O M+), 206 (4,4 M+-Bz+), 1,88 (1,6 (22), 77 (6), 65 (15). 206-HzO), 160 (2 188-C0), 147 (2,3), 132 (2,2), 134 (2), 120 (12), 119 (lo), 92 (15), 91 (100B~+), 78 C~H,,N05(403,43)Ber. : C71,5H5,25N3,5;Gef.…”