Diisopropylethylamine → [4-(4-Bromo-2,5-dichloro-phenoxy)-6-methyl-pyridin-3-yl]-(4-cyclopropyl-3,4-dihydro-2H-quinoxalin-1-yl)-methanone

Participants

Reaction Steps

To a solution of 0.17 g (0.451 mmol) 4-(4-bromo-2,5-dichloro-phenoxy)-6-methyl-nicotinic acid in 3 mL dry N,N-dimethylformamide was added 0.38 mL (2.225 mmol) N-ethyldiisopropylamine and 207 mg (0.541 mmol) 0-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HATU, commercially available, CAS RN 148893-10-1) and 94 mg (0.541 mmol) 1-cyclopropyl-1,2,3,4-tetrahydro-quinoxaline (Example 8, intermediate a). The reaction mixture was stirred at room temperature for 18 hours and then poured on 30 mL 10% aqueous sodium bicarbonate solution and 30 mL ethyl acetate. The layers were separated. The aqueous layer was extracted with 30 mL ethyl acetate and the combined organic layers were washed with 30 mL brine, dried over magnesium sulfate, filtered and concentrated under vacuum. The residue was purified by silica gel chromatography using a MPLC system (20 g silica gel column, CombiFlash Companion, Isco Inc.) with a gradient of n-heptane:ethyl acetate (100:0 to 40:60) to give 55 mg (23%) of the title compound as a light yellow solid. MS (ESI): m/z=534.018 [M+H]+.

Provenance & Evidence