Trifluoroacetic acid → HCID 131716458, compound

Participants

Reaction Steps

(3S-trans)-[[3-[(t-Butyloxycarbonyl)amino]-4-methyl-2-oxo-1-azetidinyl]oxy]acetic acid. cyclohexyl ester (2.23 g) prepared analogously to the procedure of example 91A was dissolved in a solution of 25 ml of trifluoroacetic acid and 2.5 ml of anisole at -10° C. The mixture was evaporated in vacuo 25 minutes later and the residue was stirred with ether, filtered off and dried over P2O5 to give colorless crystals of (3S)-[[3-amino-4 methyl2-oxo-1-azetidinyl]oxy]acetic acid, cyclohexyl ester, trifluoroacetate salt (yield 1.53). The salt (1.50 g) was suspended in 30 ml of acetonitrile. MSTFA (2.37 ml) was added at 0° C. and the solution was allowed to stand overnight. After evaporating in vacuo, the residue (1.75 g) was dissolved in dry tetrahydrofuran (25 ml), 1.4 g of (Z)-2-amino-α-methoxyimino)-4-thiazoleacetic acid, 1-hydroxybenzotriazole ester was added and the mixture was stirred at room temperature for 4 hours. Tetrahydrofuran was removed in vacuo at 30° C., the residue was taken up in ether, shaken with ice-cold aqueous NaHCO3 (in) and twice with cold water. The dried ethyl acetate layer was evaporated in vacuo. The resulting oil (2.14 g) chromatographed on silica gel with ethyl acetate to give 1.58 g of the title compound; melting point 85°-90° C. dec.

Provenance & Evidence