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

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8 g (35 mmol) of tert-butyl (6-chloropyridin-2-yl)carbamate (Example 24A) were initially charged in 100 ml of THF and cooled to −50° C. 55 ml (87 mmol) of butyllithium (1.6N) were added dropwise. After the dropwise addition had ended, the reaction was slowly warmed to −10° C. and stirred at 0° C. for 2 h. The mixture was then cooled again to −40° C., and 12.8 g (70 mmol) of 4-(trifluoroacetyl)morpholine (Example 21A), dissolved in 4 ml of THF, were added. The reaction solution was stirred at −40° C. for 1 h, and, at −40° C., poured into 1 l of ethyl acetate and 350 ml of ammonium chloride solution and extracted. The organic phase was separated off, dried over magnesium sulfate and concentrated on a rotary evaporator. The reaction mixture was chromatographed on silica gel (mobile phase cyclohexane/ethyl acetate 10:1). This gave 9 g (79% of theory) of the product as an oil.

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