Hydrochloric Acid → HCID 13207815, compound

Participants

Reaction Conditions

Reaction Steps

17.6 g of indole in solution in 100 ml of ether were added to a magnesium methyl iodide solution prepared from 6.5 g magnesium and 38.6 g methyl iodide in 150 ml ethyl ether. Heating under reflux took place for 2 hours and the solution was cooled to 0° C. before adding, drop by drop while stirring, a solution of 36.3 g of 1-benzyloxycarbonyl-4-piperidyl-acetyl chloride (U.S. Pat. No. 4,064,255) in 300 ml toluene. The solution was stirred for 2 hours at 10° C. and then hydrolyzed with 170 ml of 2 N hydrochloric acid. 25.8 g of 2-(1-benzyloxycarbonyl-4-piperidyl)-1-(3-indolyl)- ethanone melting at 122° C. were obtained and then converted into a tosylated derivative by the action of 15.7 g of tosyl chloride in the presence of 27.8 g potassium carbonate in 400 ml of acetone. 34.5 g of 2-(1-benzyloxycarbonyl- 4-piperidyl)-1-(1-p-toluenesulfonyloxy-3-indolyl)-ethanone were obtained and put into suspension in 600 ml ethyl ether. This suspension was added, little by little, to a magnesium methyl iodide solution prepared from 3.1 g of magnesium and 18.5 g of methyl iodide in 200 ml of ethyl ether. The mixture was stirred over night at the ambient temperature and hydrolyzed at about 5° C. with 650 ml of a 20% by weight aqueous solution of ammonium acetate. 35.5 g of 1-(1-benzyloxycarbonyl-4-piperidyl)-2-(1-tosyl-3-indolyl)-2-propanol were obtained. The piperidine protective group was then eliminated by the action of cyclohexene in the presence of aluminum chloride and 10% palladized carbon; the reagents were added at or near 0° C. in an inert atmosphere. The process was completed by heating under reflux for 4 hours. After filtration, concentration under vacuum and purification by silica gel chromatography (eluant: toluene-ethanol-diethylamine=5-5-1), 10 g of 1-(4-piperidyl)-2-(1-p-toluenesulfonyloxy-3-indolyl)-2-propanol were obtained which were used as such for the preparation of 3-[2-(4-piperidyl)-1-methyl-ethyl]-indole.

Provenance & Evidence