Sodium Bicarbonate → HCID 131715217, compound

Participants

Reaction Steps

7-Amino-3-azidomethylceph-3-em-4-carboxylic acid (170 g.) was suspended by stirring in water (750 ml.) and sodium bicarbonate (60 g.) added carefully, followed by t-butanol (750 ml.). Bis(O-t-butyl)carbonic anhydride (170 ml.) dissolved in t-butanol (375 ml.) was added and the mixture left to stir at ambient temperature; further portions of reagent (20 ml.) in t-butanol (40 ml.) were added after 24 and 48 hours. After 72 hours, t-butanol was removed by evaporation and the aqueous residue, diluted with water to 21°, was cooled in ice. The pH was reduced to 3 with concentrated hydrochloric acid, and the precipitate filtered, and washed free of acid. After drying under vacuum, the crude product was extracted successively with 500 ml. and two 400 ml. portions of acetonitrile. The combined extracts were evaporated to a small volume and filtered to give 3-azidomethyl-7-t-butoxycarbonylaminoceph-3-em-4-carboxylic acid (84 g.), having the following n.m.r. in solvent A: 1.4(s, 9 H); 3.5(d, 2H); 4.2(d, 2H); 5.0(d, 1H); 5.4(d, 1H).

Provenance & Evidence