合成路线:The ozonolysis of p-nitrobenzyl ester of 7-amino-3-methylenecephem-4-carboxylic acid (I) in CH2Cl2 gives the p-nitrobenzyl ester of 7-amino-3-hydroxy-3-cephem-4-carboxylic acid (II),which is then condensed with thiophene-2-acetyl chloride (A) in aqueous THF to afford p-nitrobenzyl ester of 7-(thiophene-2-acetamido)-3-hydroxy-3-cephem-4-carboxylic acid (III).The chlorination of (III) with SOCl2,PCl3,POCl3,(COCl)2 or COCl2 in DMF yields p-nitrobenzyl ester of 7-(thiophene-2-acetamido)-3-chloro-3-cephem-4-carboxylic acid (IV),which is then partially hydrolyzed with dry pyridine and PCl5 giving p-nitrobenzyl ester of 7-amino-3-chloro-3-cephem-4-carboxylic acid (V).This compound can be acylated easily to p-nitrobenzyl ester of 7-(D-alpha-phenylglycylamido)-3-chloro-3-cephem-4-carboxylic acid (VI),which is finally hydrogenolyzed with Zn and conc.HCl.An alternative way starting also from (V) is its hydrogenolysis with H2 over Pd/C in THF-MeOH giving the 7-amino-3-chloro-3-cephem-4-carboxylic acid (VII),which is then acylated as usual.
参考文献标题:Chemistry of cephalosporin antibiotics.30.3-Methoxy- and 3-halo-3-cephems
文献作者:Chauvette,R.R.; Pennington,P.A.
参考来源:J Med Chem 1975,18(4),403-8
合成路线:The ozonolysis of p-nitrobenzyl ester of 7-amino-3-methylenecephem-4-carboxylic acid (I) in CH2Cl2 gives the p-nitrobenzyl ester of 7-amino-3-hydroxy-3-cephem-4-carboxylic acid (II),which is then condensed with thiophene-2-acetyl chloride (A) in aqueous THF to afford p-nitrobenzyl ester of 7-(thiophene-2-acetamido)-3-hydroxy-3-cephem-4-carboxylic acid (III).The chlorination of (III) with SOCl2,PCl3,POCl3,(COCl)2 or COCl2 in DMF yields p-nitrobenzyl ester of 7-(thiophene-2-acetamido)-3-chloro-3-cephem-4-carboxylic acid (IV),which is then partially hydrolyzed with dry pyridine and PCl5 giving p-nitrobenzyl ester of 7-amino-3-chloro-3-cephem-4-carboxylic acid (V).This compound can be acylated easily to p-nitrobenzyl ester of 7-(D-alpha-phenylglycylamido)-3-chloro-3-cephem-4-carboxylic acid (VI),which is finally hydrogenolyzed with Zn and conc.HCl.An alternative way starting also from (V) is its hydrogenolysis with H2 over Pd/C in THF-MeOH giving the 7-amino-3-chloro-3-cephem-4-carboxylic acid (VII),which is then acylated as usual.
参考文献标题:Cefaclor
文献作者:Bogan,J.A.; Castar,J.
参考来源:Drugs Fut 1977,2(6),369
产品链接: CAS No. 53994-73-3›› 产品链接: CAS No.70356-03-5››