Ammonium Chloride → tert-Butyl (6-chloro-3-propanoylpyridin-2-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

Under argon, 7.00 g (30.6 mmol) of tert-butyl(6-chloropyridin-2-yl)carbamate (Example 3A) were initially charged in 90 ml of THF and cooled to −50° C. 47.8 ml (76.5 mmol) of butyllithium (1.6 M in hexane) were added dropwise. After the dropwise addition had ended, the reaction was slowly warmed to 0° C. and kept at 0° C. for 1 h. The mixture was then cooled again to −40° C., and 9.85 g (61.2 mmol) of N-propionylmorpholine dissolved in 10 ml of THF were added. The reaction solution was stirred at −40° C. for another 1 h and then, at −40° C., poured into 1 l of ethyl acetate and 350 ml of ammonium chloride solution, and the organic phase was separated off and washed with water and saturated aqueous sodium bicarbonate solution. The organic phase was dried over magnesium sulfate and concentrated on a rotary evaporator. The crude product was chromatographed on silica gel (mobile phase cyclohexane/ethyl acetate 10:1 to 1:1). This gave 2800 mg (32% of theory) of the product.

Provenance & Evidence