ketobemidone is white or almost white, crystalline powder.
Ketobemidone,Shanghai
Lancheng
Corporation
ketobemidone is an opioid analgesic. Used as a substitute to morphine for postoperative pain in children.
ChEBI: Ketobemidone is a member of piperidines.
The process includes the following steps:
1. 80 weight parts (w.p.) powder of sodium amide was added to 147 w.p. 3-
methoxy-benzylcyanide, 156 w.p. N,N-bis(2-chloroethyl)-N-methylamine and
350 w.p. toluene in 6-8 portions by stirring at 40°-45°C. The mixture was
slowly heated to 100°-105°C with stirring for 1 hour at this temperature.
Some water was added after cooling, the toluene layer was treated with
diluted HCl and it therefrom was adjusted to a alkaline pH by addition of
sodium hydroxide, extracted with ether and the ether layer dried over
Na2CO3. The solvent was removed; the distillation of the residue gave 4-cyan-
4-(3-metoxyphenyl)-1-methylpiperidine as a colorless oil; BP 150°C at 2
mm/Hg, hardened by standing; MP 44°C. The yield was 65-68%.
2. The solution of ethyl magnesium bromide from 36 w.p. magnesium and
165 w.p. ethyl bromide in 700 w.p. ether was added to 230 w.p. above
cyanide in 330 w.p toluene. The mixture was refluxed for 1 hour. Then the
ether was slowly distilled and the residue was stood for 1 hour at water bath
temperature. After cooling with an ice the mixture was acidified by addition of
HCl to adjust the congo acid pH. 4-(3-Methoxyphenyl-1-methyl-4-
propipnylpiperidine was prepared by a saturation of above solution with NH3
and it therefrom was dried over K2CO3 and distilled to give a colorless product
BP 184°-185°C at 6 mm/Hg.
3. The mixture 261 w.p 4-(3-methoxyphenyl)-1-methyl-4-propipnylpiperidine
and 750 w.p. HBr (BP 126°C) was refluxed for 1 hour. Then 2/3 of acid was
distilled on an oil bath and the hot water was added to the rest. The title
product was precipitated by NH3 as the oil that became hard and after
recrystallisation from ethylacetate had MP 156°-157°C.
