反应详情

温度

20 °C

Tertiobutyl 3-(3-benzyloxymethyl-2-methoxy-4-pyridyl)-3-hydroxy-pentanoate (40 g; 100 mmol) is treated with trifluoroacetic acid (150 ml) and the reaction medium is agitated for 18 hours at 20° C. After evaporation of the trifluoroacetic acid, methylene chloride (200 ml) is poured in and a saturated solution of sodium bicarbonate is introduced until the pH=7.5-8. After decantation, the aqueous phase is washed with 100 ml of methylene chloride. The pH of the aqueous phase is then adjusted to 1 by the addition of a solution of 6N hydrochloric acid. The product is then extracted from the aqueous phase with methylene chloride (2 times 200 ml). The solution is dried over magnesium sulphate and concentrated. The 3-(3-benzyloxymethyl-2-methoxy-4-pyridyl)-3-hydroxy-pentanoic acid (31.1 g; 90 mmol) thus obtained, taken up in isopropyl alcohol (30 ml), is treated with a solution of quinidine (29.2 g; 90 mmol) in isopropyl alcohol (30 ml) at 50° C. under agitation until complete dissolution. Then the reaction medium is left so that temperature reduces to 40° C., the agitation is stopped and the temperature allowed to drop to 20° C. The medium is taken to 0° C. without agitation then maintained at this temperature for 16 hours. Then the temperature is allowed to rise to 20° C. and agitation is carried out until crystallization. The medium is diluted with isopropyl alcohol then filtered The precipitate is rinsed with isopropyl alcohol. The salt of the (+) enantiomer precipitates (m=26.6 g) while the salt of the (−) enantiomer remains in solution in the isopropyl alcohol. Thus the filtrate is recovered which is concentrated in order to produce an oil (34 g) which is used without other purification in the following stage.

1. customAfter evaporation of the trifluoroacetic acid, methylene chloride (200 ml)
2. additionis poured in and a saturated solution of sodium bicarbonate
3. additionis introduced until the pH=7.5-8
4. washAfter decantation, the aqueous phase is washed with 100 ml of methylene chloride
5. additionThe pH of the aqueous phase is then adjusted to 1 by the addition of a solution of 6N hydrochloric acid
6. extractionThe product is then extracted from the aqueous phase with methylene chloride (2 times 200 ml)
7. dry with materialThe solution is dried over magnesium sulphate
8. concentrationconcentrated