Stereoselective reduction of 2- or 3-substituted 4-piperidones with sodium borohydride
US4496732A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1983 |
| Grant date | Jan 29, 1985 |
| Priority date | — |
| Expiry date | Mar 14, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D211/44
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A stereoselective reduction of 2- or 3-substituted 4-piperidones of the formula ##STR1## where R.sub.1 is hydrogen, loweralkyl or benzyl and R.sub.2 is methyl or ethyl, to the di-equatorial isomer of the corresponding 4-piperidinol is described. Said reduction is conducted by use of sodium borohydride in a protic solvent medium at a temperature substantially lower than ambient temperature in the presence of an effective amount of an inorganic acid. Under favorable reaction conditions, the stereoselectivity of the reduction is so high that simple crystallization of the reaction product affords the pure isomer in a commercially acceptable and advantageous process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.