Réaction #1729

Équation de réaction

3-hexyl-5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl-carboxylic acid

benzyl 6-hydroxy-nicotinate

dicyclohexylcarbodiimide

→

benzyl 6-(3-hexyl-5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl-carbonyloxy)-nicotinate

Rendement 57.0%

Solvants

methylene chloride

methylene chloride

Conditions de réaction

Traitement

1. 1
   workup.ADDITIONpoured into ice-cold aqueous ammonium chloride solution
2. 2
   Extractionextracted several times with ether
3. 3
   Lavagewashed with water
4. 4
   Séchagedried over sodium sulfate
5. 5
   Autreevaporated
6. 6
   FiltrationThe crude product, for the most part crystalline, was filtered over silica gel (eluent hexane/ethyl acetate=9:1)
7. 7
   Autrerecrystallized from hexane
8. 8
   Autrecrystallization of the mother liquor

Mode opératoire

6 g of 3-hexyl-5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl-carboxylic acid were dissolved in 180 ml of methylene chloride. After the addition of a solution of 4.8 g of benzyl 6-hydroxy-nicotinate in 160 ml of methylene chloride and of 2.3 g of 4-dimethylaminopyridine, the solution was cooled to 0° C. and treated with 4.4 g of dicyclohexylcarbodiimide. The reaction mixture was stirred at 0° C. for 1 hour and at room temperature for 2 hours, thereafter poured into ice-cold aqueous ammonium chloride solution, extracted several times with ether, washed with water, dried over sodium sulfate and evaporated. The crude product, for the most part crystalline, was filtered over silica gel (eluent hexane/ethyl acetate=9:1) and recrystallized from hexane. After repeated crystallization of the mother liquor there were obtained all together 5.7 g of benzyl 6-(3-hexyl-5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl-carbonyloxy)-nicotinate in colorless crystals, m.p. 94°-95° C.

Source