Indole dehydro phthalides and naphthalides
US3941807A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 28, 1974 |
| Grant date | Mar 2, 1976 |
| Priority date | — |
| Expiry date | Feb 28, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C8/48
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
This invention relates to a process of preparing phthalein indicator dyes including phthalides and naphthalides derived from certain hydroxy-substituted carbocyclic aryl compounds, such as phenols, and from certain N-heterocyclic aryl compounds, such as indoles, and to a process of preparing novel intermediates useful therein. According to the present invention, the selected carbocyclic compound or the selected N-heterocyclic compound is reacted with phthalaldehydic or naphthalaldehydic acid to form the corresponding (na)phthalidyl adduct which is treated with an oxidizing agent to yield the subject intermediates. To prepare the indicator dye, the intermediate, i.e., the oxidation product thus obtained is then reacted with a carbocyclic or heterocyclic aryl compound to yield the corresponding indicator dye. The oxidation products comprising the novel intermediates of the present invention may be dehydro or hydrated (na)phthalidyl adducts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.