4-Acetylmorpholine → tert-Butyl [6-chloro-3-acetylpyridin-2-yl]carbamate

Participants

Reaction Conditions

Reaction Steps

0.65 g (2.9 mmol) of tert-butyl (6-chloropyridin-2-yl)carbamate (Example 105A) is introduced into 10 ml of THF and cooled to −50° C. 4.5 ml (7.2 mmol) of butyllithium (1.6 M) are added dropwise. After the dropwise addition is complete, the reaction is slowly warmed to −10° C. and kept at 0° C. for 2 h. It is then cooled to −40° C. again, and 740 mg (5.7 mmol) of N-acetylmorpholine dissolved in 4 ml of THF are added. The reaction solution is stirred at −40° C. for 1 h and then, at −40° C., poured into 1 l of ethyl acetate and 350 ml of ammonium chloride solution and extracted. The organic phase is separated off, dried over magnesium sulphate and concentrated in a rotary evaporator. The reaction mixture is chromatographed on silica gel (mobile phase cyclohexane/ethyl acetate 2:1). 218 mg (28% of theory) of the product are obtained as an oil.

Provenance & Evidence