N-bromobutanimide → t-Butyl 2-bromo-3-bromomethyl-7-phenylacetamido-3-cephem-4-carboxylate 1-oxide

Participants

Reaction Steps

The reference 2-bromo-3-bromomethyl compound in the above HPLC analysis was prepared as follows: To a solution of 4.6 g (9.5 mmoles) of t-butyl 2-bromo-7-phenylacetamido-3-methyl-3-cephem-4-carboxylate 1-oxide in 350 ml of methylene chloride cooled in ice and irradiated with a 150 W tungsten lamp were added in portions over a period of 105 minutes 3.05 g (17.1 mmoles) of N-bromosuccinimide. After the addition was completed, the irradiation was continued for another hour and the orange-colored solution was concentrated to dryness by evaporation at low temperature. The residue was chromatographed on silica gel (elution with methylene chloride/acetone; first 72:1, then 49:1, v/v) to obtain 1.4 g (26%) of t-butyl 2-bromo-3-bromomethyl-7-phenylacetamido-3-cephem-4-carboxylate 1-oxide.

Provenance & Evidence