Methanol → 2,3-Dihydroxybutanedioic Acid

Participants

Reaction Steps

To a mixture of racemic ethyl 3-[3-iodo-4-[2-(phenoxazin-10-yl)ethoxy]phenyl]-2-ethoxypropionate of the formula (4) (45 g) obtained according to the procedure described in step (vii) above and methanol (225 ml), was added aqueous 10% sodium hydroxide solution (225 ml) slowly at room temperature over a period of 10-15 minutes. The reaction mixture was stirred at the same temperature for a period of 2-4 h. The progress of the reaction was monitored by TLC. After the complete hydrolysis of the compound of the formula (4), the reaction mass was diluted with water (225 ml) and washed with toluene to remove the impurities. The aqueous layer was acidified with dilute hydrochloric acid and extracted with toluene. Combined toluene extracts were washed with water and concentrated under reduced pressure to half the volume and treated with activated charcoal. Filtration of the charcoal followed by concentration of toluene to ˜50 ml and precipitation with pet. ether afforded racemic acid of the formula (5) as an off-white to white solid, which was filtered and dried at room temperature (˜30° C.), (38-39 g, 90-92%).

Provenance & Evidence