1-Chloroethyl chloroformate → 3-[(1S)-1-(3,5-Difluorophenyl)-2-fluoro-2-methylpropyl]azetidine

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Reaction Steps

A sample of 2.25 g (5.5 mmole) of 3-[(1S)-1-(3,5-difluorophenyl)-2-fluoro-2-methylpropyl]-1-(diphenylmethyl)azetidine (Step 2 of Example 76) was dissolved in 15 mL of THF and 1.1 mL (10 mmole) of 1-chloroethyl chloroformate was added. The solution was stirred at room temperature. After 2 h, the solution was concentrated under reduced pressure and the residue was dried under high vacuum for 1 h. The residue was dissolved in 20 mL of methanol and heated to reflux for 6 h. The solution was concentrated and the residue was partitioned between 100 mL ether and 50 mL of 1:1 saturated Na2CO3 solution-1M NaOH. The aqueous layer was washed with 3 portions of 100 mL ether and the combined organic extracts were washed with NaHCO3, then brine, then concentrated. The oily residue was applied to a silica gel column packed in 20% ethyl acetate-hexane and the column was washed with 5 column volumes of 20% ethyl acetate-hexane, then with dichloromethane, with 10% methanol in dichloromethane and finally with 80:20:2 dichloromethane-methanol-ammonium hydroxide. Homogenous fractions were concentrated to afford the title compound, which was not further purified but was used directly in the next step; Mass Spectrum: m/e=244 (M+1).

Provenance & Evidence