Method of forming a photographic washout coupler (BARC) using a strong base
US5286859A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 1992 |
| Grant date | Feb 15, 1994 |
| Priority date | — |
| Expiry date | Jun 29, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C7/30576
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A method of forming a photographic coupler (A) having the formula: EQU (SOL).sub.x --COUP--(R.sup.1).sub.y --(R.sup.2).sub.z --BLEACH comprising: PA0 (a) providing a coupler (B) having a coupling-off group represented by the formula: ##STR1## (b) reacting said coupling-off group of coupler (B) with phosgene to provide a chloroformate coupling-off group of coupler (B) PA0 (c) reacting said chloroformate coupling-off group of coupler (B) in the presence of a strong base selected from the group consisting of triethylamine, N,N-diisopropylethylamine, and tetramethylguanine with: EQU R.sup.14 --R.sup.13 --SH PA0 to provide the R.sup.2 group and the BLEACH group of the coupler (A).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.