Chlorotrimethylsilane → (2S,3S)-3-Amino-2-methyl-4-oxo-1-azetidinesulfonic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 531 mg (0.001 mole) of (3S-trans)-4-methyl-2-oxo-3-(phenyloxycarbonylamino)-1-azetidinesulfonic acid, tetrabutylammonium salt in 10 ml of 1,2-dichloroethane is treated with 278 μl of triethylamine and 250 μl of trimethyl chlorosilane and the solution refluxed for 75 minutes. An aliquot of the reaction mixture shows intense IR absorption of 2270 cm-1 (indicative of the isocyanate group) and almost complete disappearance of the 1745 cm-1 band (for the urethane function) in addition to a strong absorption at 1770 cm-1 (β-lactam). The solution is refluxed for 20 hours (no change in IR), cooled to 0° C., and 2 ml of 88% formic acid is added. After 2.5 hours at room temperature the slurry is filtered to give 118 mg of (3S-trans)-3-amino-4-methyl-2-oxo-1-azetidinesulfonic acid, inner salt.

Provenance & Evidence