65404-46-8

Upstream product

• 84532-34-3 para-nitrobenzyl 7-(R)-phenoxyacetamido-3-hydroxy-3-cephem-4-carboxylate 
• 2622-08-4 tri(O-methylphenyl)phosphite 
• 53994-83-5 (6R)-7t-amino-3-chloro-8-oxo-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid 4-nitro-benzyl ester 
• 701-99-5 Phenoxyacetyl chloride 
• 57562-43-3 (6R,7R)-3-Hydroxy-8-oxo-7-(2-phenoxy-acetylamino)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid 4-nitro-benzyl ester 

Downstream Products

• 115463-68-8 2-<1-(phenoxyacetamido)-2-methoxy-2-oxoethylidene>-3,6-dihydro-2H-1,3-thiazine-4-carboxylic acid methyl ester 
• 73426-29-6 (6R)-3-chloro-8-oxo-7t-(2-phenoxy-acetylamino)-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid 

Relevant academic research and scientific papers

Catalytic transfer hydrogenolysis of 4-nitrobenzyl esters of cephalosporins

Cephalosporins 1a-d have been selectively hydrogenolysed to their corresponding acids 2a-d without isomerisation of the cephem double-bond using anhydrous ammonium formate or phosphinic acid as catalytic transfer agents in the presence of 10% pd/C.

An efficient method for the reduction of cephalosporin sulfoxides

An efficient and convenient method for the reduction of cephalosporin sulfoxides to their corresponding sulfides by Lawesson reagent is reported.

Kinetic differences in the chlorination of cephalosporin versus carbacephalosporin enols: Evidence of sulfur neighboring group participation

Intermediates in the chlorination of carbacephalosporin and cephalosporin enols with chlorotriphenoxyphosphonium chloride, (PhO)3P+Cl Cl-, have been characterized at low temperatures by NMR. 31P NMR has been used to determine the rate constants and Arrhenius activation energies for the chlorination of the cephalosporin enol 1b and the carbacephalosporin enol 1c. The results show a 3.7 kcal/mol lower activation energy for the chlorination of the cephalosporin enol. Semiempirical and ab initio calculations have been employed to evaluate chloride attack and phosphate departure for model cephalosporin and carbacephalosporin enols. The experimental and computational results are consistent with a chlorination mechanism that involves rapid, reversible chloride addition to an intermediate enol phosphonium species followed by rate-limiting phosphate departure. The lower activation energy for phosphate departure in the cephalosporin case is attributed to sulfur neighboring group participation.

Halogenating reagents

Novel halogenating agents are derived from triaryl phosphites and chlorine or bromine. They are useful in converting 7-acylamino-3-hydroxy-3-cephem compounds to 7-acylamino-3-halo-3-cephems and the corresponding C-7 imino halide cephem derivatives.