Dicyclohexylcarbodiimide → 1,4-dihydro-4-oxo-N-(2-oxo-1-imidazolidinyl)-5-(phenylmethoxy)-2-pyridinecarboxamide

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Reaction Steps

1,4-Dihydro-4-oxo-5-(phenylmethoxy)-2-pyridinecarboxylic acid (12.26 g, 0.05 mol) and 1-amino-2-imidazolidinone (5.56 g, 0.055 mol) were suspended in 120 ml of dimethylformamide. To the suspension was added 0.3 g of dimethylaminopyridine and 0.4 g of N-hydroxybenzotriazole. After stirring for 30 minutes at room temperature, a solution of 11.35 g of dicyclohexylcarbodiimide (0.055 mol) in 50 ml of dimethylformamide was added dropwise and the mixture was stirred overnight at room temperature. The precipitate (dicyclohexylurea) was filtered off and the filtrate evaporated in vacuo. The remaining syrup crystallized on treatment with aqueous sodium bicarbonate, yielding 11.7 g of the title compound, melting point 158°-160° C. An additional crop of 0.8 g of product, melting point 162°-164° C., crystallized from the aqueous filtrate.

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