Sodium Methoxide → 4-Quinazolineacetic acid, 8-fluoro-3,4-dihydro-2-[4-(3-methoxyphenyl)-1-piperazinyl]-3-[2-methoxy-5-(trifluoromethyl)phenyl]-

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Reaction Steps

(R)-{8-Fluoro-2-[4-(3-methoxyphenyl)piperazin-1-yl]-3-(2-methoxy-5-trifluoromethylphenyl)-3,4-dihydroquinazolin-4-yl}acetic acid (50 g) is dissolved in acetonitrile (500 ml) and treated with sodium methoxide (30% strength in methanol, 32.4 ml) and then stirred under reflux for 60 h. After cooling to room temperature, the mixture is concentrated to one half in vacuo, then it is adjusted to pH 7.5 using hydrochloric acid (20% strength, ca. 20 ml), MIBK (200 ml) is added and it is readjusted to pH 7 using hydrochloric acid (20% strength). The phases are separated, and the organic phase is dried over sodium sulphate and concentrated in a rotary evaporator to give a hard foam. The residue is dissolved in ethanol (150 ml) and concentrated, then again dissolved in ethanol (150 ml) and concentrated. A total of 54.2 g of (±)-{8-fluoro-2-[4-(3-methoxyphenyl)piperazin-1-yl]-3-(2-methoxy-5-trifluoromethylphenyl)-3,4-dihydroquinazolin-4-yl}acetic acid are thus obtained in quantitative yield as an amorphous solid.

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