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 1M solution of lithium bis-trimethysilylamide in THF are added dropwise to a solution of 1059 mg (3 mmol) of p-nitrobenzyl (4-tert-butylthio-2-oxo-1-azetidinyl)acetate in 7 ml of dry THF at -70° C., and a solution of 382 mg of pivaloyl chloride in 1 ml of THF is subsequently added dropwise at -70° C., and the reaction mixture is then stirred for 30 minutes at the same temperature. The mixture is diluted with 200 ml of toluene and a little aqueous acetic acid is added. The organic phase is washed with 100 ml of 2N aqueous hydrochloric acid and twice with saturated sodium chloride solution (100 ml), the organic phase is dried using MgSO4, and the solvent is evaporated in vacuo to give a dark red oil. Purification of the crude product over 40 g of silica gel using toluene: ethyl acetate (9:1) gives 795 mg of a non-crystalline solid. IR spectrum in methylene chloride: 2970, 1770, 1760, 1715, 1610, 1530, 1370, 1350, 1315, 1180, 995, 845 cm-1.

Provenance & Evidence