Sodium Bicarbonate → (R)-2-(8-Fluoro-3-(2-methoxy-5-(trifluoromethyl)phenyl)-2-(4-(3-methoxyphenyl)piperazin-1-yl)-3,4-dihydroquinazolin-4-yl)acetic acid

Participants

Reaction Steps

(2R,3R)-2,3-Bis[(4-methylbenzoyl)oxy]succinic acid-methyl{8-fluoro-2-[4-(3-methoxyphenyl)-piperazin-1-yl]-3-[2-methoxy-5-(trifluoromethyl)phenyl]-3,4-dihydroquinazolin-4-yl}acetate (1:1 salt) (170 g) are suspended in ethyl acetate (850 ml) and shaken with saturated aqueous sodium bicarbonate solution (850 ml) until both phases are clear (ca. 5 min.). The phases are separated, and the solvent of the organic phase is replaced at normal pressure with 1,4-dioxane up to a final temperature of 99° C. (a total of 2.55 l of solvent is distilled off and 2.55 l of 1,4-dioxane are employed in portions). The mixture is cooled to room temperature and stirred at room temperature for 18 h with 1N sodium hydroxide solution (525 ml). Subsequently, the pH is adjusted to 7.5 using concentrated hydrochloric acid (ca. 35 ml), MIBK (850 ml) is added, then the pH is readjusted to 7.0 using concentrated hydrochloric acid (ca. 10 ml). The phases are separated, and the organic phase is dried over sodium sulphate and concentrated. The residue is dissolved in ethanol (350 ml) and concentrated, then again dissolved in ethanol (350 ml) and concentrated at 50° C. A total of 91.6 g of (R)-{8-fluoro-2-[4-(3-methoxyphenyl)piperazin-1-yl]-3-(2-methoxy-5-trifluoromethylphenyl)-3,4-dihydroquinazolin-4-yl}acetic acid are thus obtained as an amorphous solid, corresponding to 91.6% of theory.

Provenance & Evidence