Ammonium Chloride → tert-Butyl[6-chloro-3-(trifluoroacetyl)pyridin-2-yl]carbamate

Participants

Reaction Conditions

Reaction Steps

8 g (35 mmol) of tert-butyl (6-chloropyridin-2-yl)carbamate (Example 1A) were initially charged in 100 ml of THF and cooled to −50° C. 55 ml (87 mmol) of butyllithium (1.6 N) were added dropwise. After the dropwise addition had ended, the reaction was warmed gradually to −10° C. and stirred at 0° C. for 2 h. Subsequently, the mixture was cooled again to −40° C., and 12.8 g (70 mmol) of 4-(trifluoroacetyl)morpholine (Example 6A), dissolved in 4 ml of THF, were added. The reaction solution was stirred at −40° C. for 1 h, then poured at −40° C. onto 1 l of ethyl acetate and 350 ml of ammonium chloride solution, and extracted. The organic phase was removed, dried over magnesium sulphate and concentrated on a rotary evaporator. The reaction mixture was chromatographed on silica gel (eluent: cyclohexane/ethyl acetate 10:1). 9 g (79% of theory) of the product were obtained as an oil.

Provenance & Evidence