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

Temperature

5 °C

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.

1. additionTo the reaction mixture was added 578 cc
2. additionAfter the addition
3. temperatureheated
4. temperatureat reflux for 1 hour
5. temperatureThe reaction mixture was cooled to about 25° C.
6. customThe alkaline reaction mixture
7. extractionwas extracted with diethyl ether
8. washThe ethereal extracts were washed with water
9. dry with materialdried over sodium sulfate
10. filtrationAfter filtering the drying agent
11. customthe solvent was evaporated under reduced pressure
12. customto provide 47 g

ORD record

ord-42d7a4f2a8f340a39e41d8bed887bbc0

Source dataset

uspto-grants-1980_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04191771