تفاعل #747262

معادلة التفاعل

L-cinchonidine

cyclohexyl-hydroxy-thiophen-2-yl-acetic acid

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L-cinchonidine

titled compound

(S)-Cyclohexyl-hydroxy-thiophen-2-yl-acetic acid

المذيبات

toluene

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةthe mixture is heated
2. 2
   درجة الحرارةto reflux for 70 minutes
3. 3
   درجة الحرارةAfter further cooling to 40° C.
4. 4
   أخرىis placed in the fridge overnight
5. 5
   ترشيحThe resulting solid is filtered
6. 6
   غسيلwashed with toluene
7. 7
   أخرىdried in vacuo
8. 8
   أخرىoccurring at 85° C.

الإجراء التجريبي

L-cinchonidine (30.2 g, 0.103 mol) is added to crude cyclohexyl-hydroxy-thiophen-2-yl-acetic acid (49.3 g, 103 mol assuming 50% purity of crude) followed by toluene (2.2 litres) and the mixture is heated to reflux for 70 minutes. The resulting solution is allowed to cool slowly and at 65° C., the solution is seeded. After further cooling to 40° C., the solution is placed in the fridge overnight. The resulting solid is filtered, washed with toluene and dried in vacuo. The recrystallisation process from toluene is repeated for a second time with seeding occurring at 85° C. to afford the titled compound as a salt of L-cinchonidine in 98% enantiomeric excess. The salt is added to a stirred mixture of 1M HCl (40 ml) and diethyl ether (500 ml) and stirring continues until a solution forms. The organic portion is separated, washed with brine (400 ml), dried over MgSO4 and concentrated in vacuo to give the titled compound in 98% enantiomeric excess.

المصدر