Acetic Acid → 1,3-Dimethyl-4-n-propyl-4-(3-methoxyphenyl)-1,4,5,6-tetrahydropyridine

Participants

Reaction Conditions

Reaction Steps

A solution of 50 g. of 1,3,4-trimethyl-4-phenyl-1,4,5,6-tetrahydropyridine in 2600 cc. of tetrahydrofuran containing 38 g. of sodium borohydride was stirred and cooled to 5° C. in an ice-water bath. To the reaction mixture was added 578 cc. of glacial acetic acid at a rate such as to maintain the temperature of the reaction mixture between 5° C. and 10° C. After the addition was complete, the reaction mixture was stirred at 10° C. for 1/2 hour and then heated at reflux for 1 hour. The reaction mixture was cooled to about 25° C. and 25 percent aqueous sodium hydroxide was added to adjust the pH to 11.5. The alkaline reaction mixture was extracted with diethyl ether. The ethereal extracts were washed with water and dried over sodium sulfate. After filtering the drying agent, the solvent was evaporated under reduced pressure to provide 47 g. of essentially pure trans-1,3,4-trimethyl-4-phenylpiperidine. B.P. 90°-92° C. at 0.15 mm/Hg.

Provenance & Evidence