2-Carboxy-4-oxo-4H,6H-(2)-benzopyrano-(3,4-f)-(1)-benzopyrans and esters and salts thereof
US3987186A · kind A · utility
3Cited by
1References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 7, 1975 |
| Grant date | Oct 19, 1976 |
| Priority date | — |
| Expiry date | Feb 7, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D311/80
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Compounds of the formula ##SPC1## Wherein the PA1 R.sub.1 ' s are hydrogen, alkyl of 1 to 3 carbon atoms or together a double-bonded oxygen, PA1 R.sub.2 is hydrogen, fluorine, chlorine, methyl, hydroxyl, methoxy, hydroxy-ethoxy, nitro or --SO.sub.3 H, PA1 R.sub.3 is hydrogen, fluorine, chlorine or methoxy, PA1 R.sub.4 is hydrogen, methyl or methoxy, PA1 R.sub.5 is hydrogen, fluorine, chlorine or methyl, and PA1 R.sub.6 is hydrogen or alkyl of 1 to 8 carbon atoms, and, when R.sub.6 is hydrogen, salts thereof formed with an inorganic or organic base; the compounds as well as the salts are useful as antiallergics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.