9-Dialkylamino-spiro [6H-[1]benzopyrano[3,2-g]quinoline-6,1'(3'H)-isobenzofuran]-3'-one compounds and pressure-sensitive recording system therewith
US4169183A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 3, 1978 |
| Grant date | Sep 25, 1979 |
| Priority date | — |
| Expiry date | May 3, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D215/20
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Disclosed are normally substantially colorless chromogenic 9-dialkylamino-spiro[6H-[1]benzopyrano[3,2-g]quinoline-6,1'(3'H)-isobenzof uran]-3'-one color precursor compounds having the following structural formula: ##STR1## wherein each R.sub.1 represents a lower alkyl group having from one to five carbon atoms and wherein each of R.sub.2 and R.sub.3 represents either a methyl group or a group which includes a methylene bridge resonance path having up to four carbon atoms, but wherein when R.sub.3 is a methylene bridge resonance path-containing group, R.sub.2 is not a methyl group. These compounds are initially substantially colorless but are capable of becoming highly colored when brought into reactive contact with many Lewis acid materials and the like. Accordingly, these compounds are highly useful as a component of pressure-sensitive copying papers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.