Phthalide derivatives useful as colorless chromogenic material
US4730057A · kind A · utility
4Cited by
1References
1Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1986 |
| Grant date | Mar 8, 1988 |
| Priority date | — |
| Expiry date | Jan 10, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D405/14
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A new phthalide derivative useful as a colorless chromogenic material has the following formula: ##STR1## wherein A and n have the same meaning as defined hereinbefore.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.