Diisopropylethylamine → 3-amino-6-bromo-N-(2-fluorophenylcarbonyl)pyrazine-2-carbohydrazide

Participants

Reaction Steps

To a suspension of 2-fluorobenzohydrazide (2 g, 12.98 mmol), 3-amino-6-bromo-pyrazine-2-carboxylic acid (2.830 g, 12.98 mmol), and TBTU (5.002 g, 15.58 mmol) in DMF (20.00 mL) was added DIPEA (3.691 g, 4.974 mL, 28.56 mmol). The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was diluted with water (20 mL) and extracted with EtOAc (3×20 mL), the combined organic extracts were washed with water (3×20 mL) and brine (1×20 mL), dried over MgSO4 and concentrated in vacuo. The residue was then triturated with acetonitrile and fluted and dried to give 3-amino-6-bromo-N-(2-fluorophenylcarbonyl)pyrazine-2-carbohydrazide as an orange solid. This was taken up in MeCN (20.00 mL) and added bromo(triphenyl)phosphonium (5.331 g, 15.58 mmol) was added followed by DIPEA (3.691 g, 4.974 mL, 28.56 mmol). The reaction mixture was stirred for 30 min, and then filtered. The solid was washed with acetonitrile to give the product as a yellow solid (1.46 g, 67%); 1H NMR (400 MHz, DMSO) d 7.48-7.54 (m, 2H), 7.75 (m, 3H), 8.12 (m, 1H) and 8.45 (m, 1H) ppm; MS (ES+) 338.03

Provenance & Evidence