Process for the preparation of 3-carboxy-4-hydroxybenzaldehides and derivatives thereof
US5783737A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 24, 1997 |
| Grant date | Jul 21, 1998 |
| Priority date | — |
| Expiry date | Jan 24, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/255
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The present invention concerns a process for the preparation of 3-carboxy-4-hydroxybenzaldehydes and derivatives thereof from phenolic compounds carrying formyl and/or hydroxymethyl groups in the 2 and 4 positions. The invention also concerns the preparation of 4-hydroxybenzaldehydes from 3-carboxy-4-hydroxybenzaldehydes. More particularly, the invention concerns the preparation of 3-methoxy-4-hydroxybenzaldehyde and 3-ethoxy-4-hydroxybenzaldehyde, respectively known as "vanillin" and "ethylvanillin". The process for the preparation of 3-carboxy-4-hydroxybenzaldehyde is characterized in that the group in the 2 position in a phenolic compound carrying formyl and/or hydroxymethyl groups in the 2 and 4 positions is selectively oxidized to a carboxy group, and optionally a hydroxymethyl group in the 4 position is selectively oxidized to a formyl group. A successive decarboxylation step for a 3-carboxy-4-hydroxybenzaldehyde produces a 4-hydroxybenzaldehyde.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.