Sodium Hydroxide → HCID 54575439, compound

Participants

Reaction Conditions

Reaction Steps

The crude product solution of diethyl [1-(2,6-dimethyl-4-nitrophenyl)-2-oxo-1,2-dihydropyridin-3-yl]malonate in dioxane (maximum 108 mmol) was introduced as initial charge in 350 ml of water, and 35 ml of concentrated sodium hydroxide solution were slowly added. The reaction mixture was stirred for 90 min at 45° C. After cooling to RT, 100 ml of water were added, followed by washing three times with dichloromethane, and the aqueous phase (pH=14) was admixed with 270 ml of dichloromethane. At 10-15° C., 59.5 ml of concentrated hydrochloric acid were slowly added until the pH=1. Even at a weakly acidic pH, carbon dioxide started to evolve. The reaction mixture was warmed to RT and stirred for 1 h, until the gas stopped evolving. Following phase separation, the organic phase was dried over sodium sulphate, filtered and evaporated to dryness on a rotary evaporator. The residue was stirred with 200 ml of methyl tert-butyl ether for 30 min. The crystalline solid was filtered off with suction, washed with methyl tert-butyl ether and dried in vacuo. 14.8 g (47% over 2 stages) of the desired product were obtained. The mother liquor was largely concentrated, the post-precipitation was filtered off with suction, after-washed and dried in vacuo. A further 5.3 g (17% over 2 stages) of the desired product were obtained.

Provenance & Evidence