Triethylamine → 3-(3,4-dihydro-2H-thiopyran-5-yl)benzyl alcohol

Participants

Reaction Steps

534 mg of 3-(tetrahydro-3-hydroxy-3-thiopyranyl)benzaldehyde dimethyl acetal obtained by performing the same reaction as in Referential Example 35 using 3-bromobenzaldehyde dimethyl acetal and tetrahydrothiopyran-3-one as starting materials was dissolved in 5 ml of ethyl acetate, and with stirring under ice cooling, 187 microliters of methanesulfonyl chloride and 553 microliters of triethylamine were added. The mixture was stirred for 30 minutes. The triethylamine hydrochloride was separated by filtration and the solvent was evaporated. The residue was dissolved in 20 ml of benzene, and 373 mg of 90% potassium tert-butoxide was added, and the mixture was stirred at room temperature for 15 hours. Ethyl ether and water were added to the reaction mixture, and the mixture was worked up in a customary manner. The resulting 3-dihydrothiopyranylbenzaldehyde dimethyl acetal was dissolved in a mixture of 3 ml of 1 N HCl and 6 ml of tetrahydrofuran. The solution was stirred at room temperature for 3 hours. The reaction mixture was concentrated under reduced pressure, and the residue was distributed between ethyl ether and water, and worked up in a customary manner. The resulting formyl compound was dissolved in 20 ml of tetrahydrofuran, and 380 mg of lithium aluminium hydride was added. The mixture was stirred for one hour under ice cooling. The reaction mixture was poured into ice water, worked up in a customary manner and purified by silica gel column chromatography [Wakogel C-200, 20 g; eluting solvent: hexane/ethyl acetate=2/1] to give 7 mg (yield 2%) of the captioned 3-(3,4-dihydro-2H-thiopyran-5-yl)benzyl alcohol and 4 mg (yield 1%) of 3-(5,6-dihydro-2H-thiopyran-3-yl)benzyl alcohol.

Provenance & Evidence