ABSTRACT
p-Nitrobenzyl 2 beta-[(benzoyloxy)methyl]-2 alpha-methylpenam-3 alpha-carboxylate was prepared by reaction of p-nitrobenzyl 2-[2-oxo-3 alpha-bromo-4-(benzothiazol-2-yldithio)azetidin-1-yl] -2-isopropenylacetate with silver benzoate in the presence of iodine. The resulting diester was oxidized to the sulfone with potassium permanganate and hydrogen peroxide, and the bromine and p-nitrobenzyl groups were removed by hydrogenolysis to give potassium 2 beta-(benzoyloxy)methyl 2 alpha-methylpenam-3 alpha-carboxylate 1,1-dioxide. A series of related compounds, including the pivaloyl, methoxybenzoyl, p-fluorobenzoyl, and p-aminobenzoyl derivatives, were prepared in a similar way. All of these compounds were potent beta-lactamase inhibitors in vitro against the TEM beta-lactamase from Klebsiella pneumoniae A22695 and Bacteroides fragiles A22695 but less active against the beta-lactamase from Staphylococcus aureus A9606. All compounds when administered orally in a 1:1 combination with amoxicillin did not show any significant protection of mice infected with S. aureus A9606. 2 beta-(Bromomethyl)-2 alpha-methylpenam-3 alpha-carboxylic acid was prepared and reacted with silver nitrate to give the nitrate ester. Oxidation with potassium permanganate and catalytic reduction afforded 2 beta-(hydroxymethyl)-2 alpha-methylpenam-3 alpha-carboxylic acid 1,1-dioxide. 2 beta-(Bromomethyl)-2 alpha-methylpenam-3 alpha-carboxylic acid 1,1-dioxide was found to be a strong beta-lactamase inhibitor, while the 2 beta-hydroxymethyl compound showed only weak beta-lactamase-inhibiting properties.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Penicillins/chemical synthesis , beta-Lactamase Inhibitors , Amoxicillin/pharmacology , Bacteria/drug effects , Penicillins/pharmacology , Structure-Activity RelationshipABSTRACT
The synthesis and in vitro activities of a series of 2-[(methoxycarbonyl)methylene]-3-cephem-4-carboxylic acids with methyl or acetoxymethyl at the 3-position are described. The key step in the synthesis includes the stereospecific formation of the 2-[(Z)-(methoxycarbonyl)methylene] group by Pummerer rearrangement of the sulfoxides 3a and 3b. It was also possible to isomerize photochemically the C-2 olefin of 4a to its E isomer, 9. The new derivatives exhibited significant in vitro Gram-positive antibacterial activity.
Subject(s)
Cephalosporins/chemical synthesis , Structure-Activity RelationshipABSTRACT
Potassium 2 beta-(chloromethyl)-2 alpha-methylpenam-3 alpha-carboxylate 1,1-dioxide (BL-P2013) and its pivaloyloxymethyl ester were prepared by the conversion of 6-aminopenicillanic acid to p-nitrobenzyl 6 alpha-bromo-2,2-dimethylpenam-3 alpha-carboxylate 1-oxide, which was rearranged with benzoyl chloride and quinoline to p-nitrobenzyl 6 alpha-bromo-2 beta-(chloromethyl)-2 alpha-methylpenam-3 alpha-carboxylate in 65% yield. Oxidation and catalytic hydrogenation afforded BL-P2013, which was found to be a potent inhibitor of various bacterial beta-lactamases and has been found to protect amoxicillin from beta-lactamases in both in vitro and in vivo systems.
