1,1'-(Diazomethylene)bis(benzene) → Benzhydryl 7alpha-chloro-3-methyl-3-cephem-4-carboxylate

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Reaction Steps

The 7α-chloro-3-methyl-3-cephem-4-carboxylic acid (10.0 g, 0.0428 mol) was dissolved in methylene chloride (200 ml), and diphenyldiazomethane (10.8 g, 0.0557 mol) dissolved in methylene chloride (50 ml) was added dropwise over 30 minutes. The mixture was stirred at room temperature for two hours. Solvent was removed under reduced pressure and the product was purified over silica column using hexane-ethyl acetate mixture to yield benzhydryl 7α-chloro-3-methyl-3-cephem-4-carboxylate (7.8 g, 45.6%). NMR (CDCl3) δ 2.1 (s, 3H, CH3), 3.25 (bs, 2H, H-2), 4.70 (bs, 1H), 4.75 (bs, 1H), 7.0 (s, 1H, CHPh2), 7.3-7.7 (m, 10H, aromatic).

Provenance & Evidence