Method of reducing internal combustion engine emissions, and system for same
US6003305A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 2, 1997 |
| Grant date | Dec 21, 1999 |
| Priority date | — |
| Expiry date | Sep 2, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process is provided for preparing oxymorphone from morphine by: (1) reacting morphine with (1a) an acyl halide or anhydride to form 3-acylmorphine, or (1b) reacting morphine with benzyl-halide to form 3-benzylmorphine; (2) Oxidizing the 6-hydroxy group of the 3-acyl or 3-benzylmorphine so as to form the corresponding 3-acyl or 3-benzylmorphinone; and thereafter either by (3a) or (3b): (3a) introducing a .beta.-oriented hydroxy group at the 14-position of the 3-acyl- or 3-benzyl-morphinone with aqueous hydrogen peroxide and an acid at a temperature of about 15.degree. to about 70.degree. C. to form the 3-acyl or 3-benzyl-14-hydroxymorphinone; (3b) acylating the 3-acyl or 3-benzyl-morphinone with an acylating agent so as to form the dienol acylate followed by oxidizing the dienol acetate to the corresponding 3-acyl or 3-benzyl-14 -hydroxymorphinone; (4) hydrogenating the 3-acyl-14-hydroxymorphinone with a catalyst so as to form the 3-acyloxymorphone; (5) hydrolyzing the 3-acyl-oxymorphone with aqueous acidic or basic solution to form oxymorphone; (6) hydrogenating the 3-benzyl-14-hydroxymorphinone with a catalyst so as to form oxymorphone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.