Water → 6-fluoropyrido[3,4-d]pyrimidin-4-ol

Participants

Reaction Steps

A suspension of 39.0 g (246 mmol) of 5-amino-2-fluoropyridine-4-carboxylic acid hydrated with 0.15 equivalents of water, 52.01 g (500 mmol) of formamidine acetate, and 500 mL of 2-methoxyethanol was heated at reflux for 6 hours, then concentrated to a solid. The solids were treated carefully with 100 mL of 10% aqueous sodium bicarbonate while maintaining vigorous stirring. The resultant suspension was filtered, and the collected brown solids were washed well with water, then dried over P2O5 to afford 31.3 g (77%,) of product that was used directly in the next reaction. Recrystallization of a small sample from methanol gave product of mp 287° C. (dec).

Provenance & Evidence