Acetic Acid → p-Nitrobenzyl 2-(4-tert-butylthio-2-oxo-1-azetidinyl)-4,4-dimethyl-3-oxopentanoate

Participants

Reaction Steps

6 ml of a freshly prepared 1 M solution of lithium bis-trimethylsilylamide in THF are added dropwise at -70° C. to a solution of 1.059 mg (3 mmol) of p-nitro-benzyl (4-tert-butylthio-2-oxo-1-azetidinyl)-acetate in 7 ml of dry THF and then a solution of 382 mg of pivaloyl chloride in 1 ml of THF is added dropwise at -70° C. and the reaction mixture is further stirred at the same temperature during the course of 30 minutes. The mixture is diluted with 200 ml of toluene and a little aqueous acetic acid is added. Washing the organic phase with 100 ml of 2 N aqueous hydrochloric acid and washing twice with saturated sodium chloride solution (100 ml), drying the organic phase with MgSO4 and evaporating the solvent in vacuo yields a dark red oil. Purification of the crude product on 40 g of silica gel using toluene/ethyl acetate (9:1) yields 795 mg of a non-crystalline solid. IR spectrum in methylene chloride: 2970, 1770, 1760, 1715, 1610, 1530, 1350, 1315, 1180, 995, 845 cm-1.

Provenance & Evidence