反应详情

A mixture of 1 g of 4-hydroxy-7-methyl-1,8-naphthyridine-3-carboxylic acid and 25 ml of anhydrous pyridine was heated on an oil bath at 50° to 60° C while stirring. Then, 1.38 g of p-nitrophenyl trifluoroacetate were added thereto and, after the heating was interrupted, stirring was carried out for 2 hours. The precipitated crystals were collected by filtration and washed with ethanol to give 4-hydroxy-7-methyl-1,8-naphthyridine-3-carboxylic acid p-nitrophenyl ester as pale yellow crystalline powder melting at 311 to 313° C (decomp.). Yield, 1.2 g. IR νC=O 1700 cm-1 ; νNO2 1520 cm-1, 1345 cm-1.

1. temperaturewas heated on an oil bath at 50° to 60° C
2. stirringstirring
3. filtrationThe precipitated crystals were collected by filtration
4. washwashed with ethanol