96572-55-3Relevant articles and documents
Synthesis of (5R)-(Z)-6-(1-Methyl-1,2,3-triazol-4-ylmethylene)penem-3-carboxylic Acid, a Potent Broad Spectrum β-Lactamase Inhibitor, from 6-Aminopenicillamic Acid
Osborne, Neal F.,Atkins, Richard J.,Broom, Nigel J. P.,Coulton, Steven,Harbridge, John B.,et al.
, p. 179 - 188 (1994)
(5R)-(Z)-6-(1-Methyl-1,2,3-triazol-4-ylmethylene)penem-3-carboxylic acid 34 (BRL 42715) has been prepared from 6-aminopenicillanic acid 4 (6-APA) by short stereoselective and efficient route via the novel intermediate, p-methoxybenzyl (5R,6S)-6-bromopenem-3-carboxylate 17.Elaboration of 6-APA 4 to the azetidinone disulfide 10 by established methodology, followed by reductive formylation provided the crystalline C-4 formylthio-azetidinone derivative 29.Cyclization of the oxalimide 28, obtained by ozonolysis of the formylthio derivative 29, to the crystalline 6α-bromopenem ester 17 was effected by way of the phosphine-mediated carbonyl-carbonyl coupling reaction.Sequential tretment of bromopenem 17 with lithium diphenylamide, 1-methyl-1,2,3-triazole-4-carbaldehyde, and acetic anhydride gave a diastereomeric mixture of acylated bromohydrins 32; reductive elimination of this mixture afforded a separable mixture of (Z)- and (E)-triazolylmethylenepenem esters, 33 and 35 respectively.Lewis acid-mediated deprotection of ester 33 provided (5R)-(Z)-6-(1-methyl-1,2,3-triazol-4-ylmethylene)penem-3-carboxylic acid 34 (BRL 42715) as a crystalline sodium salt monohydrate.The 6-heterocyclilmethylene penems, represented by BRL 42715, are potent inhibitors of bacterial β-lactamases and their combination with an appropriate penicillin or cephalosporin results in good synergistic activity against a broad range of β-lactamase-producing bacteria.
