Sulfur Dioxide → 5-Cyano-2-{(4S)-5-cyano-3,6-dimethyl-2-oxo-1-[3-(trifluoromethyl)phenyl]-1,2,3,4-tetrahydropyrimidin-4-yl}benzenesulfonyl chloride

関与物質

反応条件

反応手順

Under argon, (4R)-4-(2-amino-4-cyanophenyl)-3,6-dimethyl-2-oxo-1-[3-(trifluoromethyl)phenyl]-1,2,3,4-tetrahydropyrimidine-5-carbonitrile (2.1 g, 5.1 mmol) was initially charged in a 2:1:1 mixture of acetic acid/conc. hydrochloric acid/water (50 ml in total) at −10° C. A solution of sodium nitrite (371 mg, 5.38 mmol) in water (2 ml) was slowly added dropwise, and the mixture was stirred at −10° C. to −5° C. for 40 min. This solution was then added to 45 ml of a suspension, pre-cooled to −10° C. and saturated with sulfur dioxide, of copper(I) chloride (101.4 mg, 1.0 mmol) in glacial acetic acid (44 ml). The mixture was stirred at 0° C. for about 30 min and then at +15° C. for 1 h (reaction monitored by HPLC and LC-MS). The reaction mixture was then once more cooled to 0° C. and then pipetted into about 300 ml of ice-cold water. The precipitate was filtered off and taken up in ethyl acetate (150 ml). The solution was washed twice with saturated sodium chloride solution, dried over sodium sulfate, filtered and concentrated under reduced pressure. The title compound was obtained as a solid (2.13 g, 77% of theory, 92% pure) which was used without further purification for subsequent reactions.

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