反应详情

A suspension of ethyl 5,8-dihydro-2-(4-acetyl-1-piperazinyl)-5-oxopyrido[2,3-d]pyrimidine-6-carboxylate (1000 g) and concentrated hydrochloric acid (800 ml) in a mixture of water (1200 ml) and ethanol (1000 ml) was refluxed for 8 hours and allowed to stand overnight. The crystals precipitated were collected, washed with ethanol, and dissolved by heating in an aqueous solution (10 liters) of sodium hydroxide (250 g). The solution was filtered, adjusted to pH 7-8 with acetic acid, and allowed to stand overnight with ice-cooling. The crystalline precipitate was collected, washed with water, and dried at 110° C. to give 5,8-dihydro-2-(1-piperazinyl)-5-oxopyrido [2,3-d]pyrimidine-6-carboxylic acid (625 g). m.p. 299°-305° C. (decomp.).

1. temperaturewas refluxed for 8 hours
2. customThe crystals precipitated
3. customwere collected
4. washwashed with ethanol
5. dissolutiondissolved
6. temperatureby heating in an aqueous solution (10 liters) of sodium hydroxide (250 g)
7. filtrationThe solution was filtered
8. waitto stand overnight with ice-
9. temperaturecooling
10. customThe crystalline precipitate was collected
11. washwashed with water
12. customdried at 110° C.