33100-27-5, 1,4,7,10,13-Pentaoxacyclopentadecane is a chiral-catalyst compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated
EXAMPLE 8 Synthesis of 4-(4-fluorobenzylidene)piperidine hydrochloride To a stirred suspension of 13.20 g of 60percent sodium hydride (in oil) containing 1.65 g of 15-crown-5 ether in 650 ml of tetrahydrofuran were added dropwise a solution of 59.78 g of N-t-butoxycarbonylpiperidone and 81.25 g of diethyl 4-fluorobenzylphosphonate in 150 ml of tetrahydrofuran under ice-cooling over 20 minutes. After stirring at room temperature for a day, a saturated aqueous sodium bicarbonate solution was added cautiously, followed by extracting with ethyl acetate. The extract was washed with a saturated aqueous sodium bicarbonate solution and a saturated aqueous sodium chloride solution, successively, and dried over anhydrous sodium sulfate, followed by removal of the drying agent by filtration. The filtrate was concentrated under reduced pressure and purified by a flash column chromatography (silica gel: Wakogel C200 (manufactured by Wako Pure Chemicals), eluent; hexane-ethyl acetate =20:1) to give 55.23 g of N-t-butoxycarbonyl-4-(4-fluorobenzylidene)piperidine as an oil, which was then crystallized by allowing to stand at room temperature overnight. m.p. 69-70¡ãC. To 55.00 g of N-t-butoxycarbonyl-4-(4-fluorobenzylidene)piperidine was added 475 ml of an ice-cooled solution of 4 N hydrogen chloride in dioxane, followed by stirring at room temperature for 2 hours. The reaction solution was concentrated under reduced pressure, and the resulting crystals were recrystallized from isopropanol to give 40.72 g of 4-(4-fluorobenzylidene)piperidine hydrochloride. m.p. 184-185.5¡ã C.
33100-27-5 1,4,7,10,13-Pentaoxacyclopentadecane 36336, achiral-catalyst compound, is more and more widely used in various.
Reference£º
Patent; Taisho Pharmaceutical Co., Ltd.; Nihon Nohyaku Co. Ltd.; US6291467; (2001); B1;,
Chiral Catalysts
Chiral catalysts – SlideShare