Butyl ether → Dexlansoprazole

Participants

Reaction Steps

Under a nitrogen atmosphere, 2-[[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridyl]methyl]thio]benzimidazole (43.2 g), toluene (175 mL), water (72.6 mg) and (+)-diethyl tartrate (4.6 mL) were mixed. Under a nitrogen atmosphere, titanium(IV) isopropoxide (3.6 mL) was added to the mixture at 50° C. to 60° C., and the mixture was stirred at the same temperature for 30 min. Under a nitrogen atmosphere, diisopropylethylamine (7.0 mL) was added to the obtained mixture at 15° C. to 25° C., cumene hydroperoxide (65 mL, content 82%) was added at −4° C. to 10° C., and the mixture was stirred at −4° C. to 10° C. for about 4 hr to give a reaction mixture. To the reaction mixture was added 25% aqueous sodium thiosulfate solution (170 g) under a nitrogen atmosphere to decompose remaining cumene hydroperoxide. Dibutyl ether (778 mL) was added to the mixture at room temperature, and the mixture was stirred at the same temperature to allow crystal precipitation. The mixture was cooled to 0° C. to 10° C. and stirred, the crystals were separated and successively washed with dibutyl ether (86 mL) cooled to 0° C. to 10° C. and municipal water (86 mL×2) (yellowish white crystals, 72 g). The wet crystals were dissolved in acetone (173 mL), and the mixture was stirred for about 30 min. To a mixture of acetone (65 mL) and municipal water (324 mL) was added dropwise the acetone solution over 10 min, and then municipal water (454 mL) was added dropwise over 20 min. After stirring at room temperature, the crystals were collected by filtration and washed with acetone/municipal water (1/5, 86 mL), and then with municipal water (43 mL) to give pale-yellowish white crystals (87 g) of (R)-2-[[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridyl]methyl]sulfinyl]benzimidazole 1.5 hydrate. The wet crystals were dissolved in acetone (173 mL), and the mixture was stirred for about 30 min. To a mixture of acetone (65 mL) and municipal water (324 mL) were added dropwise the acetone solution over about 10 min and then municipal water (454 mL) was added dropwise over about 20 min. After stirring at room temperature, the crystals were collected by filtration and washed with acetone/municipal water (1/5, 86 mL), and then with municipal water (43 mL×2) to give pale-yellow white crystals (59.8 g) of (R)-2-[[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridyl]methyl]sulfinyl]benzimidazole 1.5 hydrate.

Provenance & Evidence