Butyl Acetate → Deacetylcephalothin

Participants

Reaction Steps

A solution of sodium (6R,7R)-3-acetoxymethyl-7-(thien-2-ylacetamido)ceph-3-em-4-carboxylate (4 g) in demineralised water (80 ml) was treated with a suspension of cells obtained by culture of Rhodosporidium toruloides CBS 14, in a similar manner to that described in Example 1. Deacetylation was shown by t.l.c. to be complete after 42 hours, whereupon the reaction mixture was centrifuged to remove solid matter and the resulting solution was vigorously mixed with butyl acetate (200 ml). The pH of the mixture was adjusted to 2.2 - 2.5 by dropwise addition of concentrated phosphoric acid. The aqueous layer was separated and extracted with further butyl acetate (20 ml), a few drops of Gemex detergent being added to break the emulsion which formed. The butyl acetate fractions were combined and a 12.5% w/v solution of potassium acetate in industrial methylated spirit (≈8 ml) was slowly added thereto, until no further precipitation occurred. The precipitate was isolated by suction filtration, washed with a small volume of acetone and dried under vacuum at room temperature to give the title compound (2.87 g). This was shown by t.l.c. on cellulose-coated plates using an ethyl acetate - n-butanol - sodium acetate solvent system, comparing with an authentic sample and assaying densitometrically, to have a purity of about 75%, indicating an overall yield of 65%.

Provenance & Evidence