Sulfuric acid magnesium salt (1:1) → (+/-)-2-[3-(4-Chlorophenyl)ureido]-6-(1-cyclobutylethyl)-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxamide

Participants

Reaction Steps

To a slurry of compound A4 (400 mg, 0.860 mmol), sodium acetate (212 mg, 2.58 mmol), and magnesium sulfate (1 g) in anhydrous N,N-dimethylformamide (5 mL) was added 1-cyclobutylethanone (253 mg, 2.57 mmol). After stirring at room temperature for 5 min, sodium triacetoxyborohydride (911 mg, 4.30 mmol) was added. The reaction mixture was then heated at 50° C. for 20 h. After this time, the reaction mixture was cooled to room temperature and diluted with saturated aqueous sodium bicarbonate (10 mL), methanol (5 mL), methylene chloride (20 mL), and water (10 mL). The layers were separated and the aqueous layer back extracted with 20% methanol/methylene chloride (2×30 mL). The combined organic layers were dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash column chromatography on silica gel eluting with 2% to 6% methanol/methylene chloride to afford compound (+/−)-C1 as a white solid (199 mg, 53%): MS (M+H) 433.

Provenance & Evidence