2-Pyrazinecarboxylic acid → 1,6-Dihydro-6-oxo-1-[2-(2-pyrazinylcarbonylamino)ethyl]-3-pyridinecarboxylic acid methyl ester

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Reaction Steps

1-(2-aminoethyl)-1,6-dihydro-6-oxo-3-pyridinecarboxylic acid methyl ester (0.396 g, 2.02 mmol) was coupled with 2-pyrazinecarboxylic acid (0.251 g, 2.02 mmol) in a mixture of dichloromethane (34 ml) and dimethylformamide (35 ml) with triethylamine (1.41 ml, 10.1 mmol)and propylphosphonic acid anhydride (0.7 ml, added as a 0.7 ml ethyl acetate solution). After 18 hours, the mixture was concentrated and the residue slurried in dichloromethane and aqueous sodium bicarbonate. The layers were separated and the aqueous layer extracted with dichloromethane (2X) and the combined organic layers dried (Na2SO4). Filtration, concentration, and purification via medium pressure liquid chromotography (silica gel, 5% methanol/dichloromethane) gave the desired product, MP: 195°-197° C.

Provenance & Evidence