Process for preparing 5-alkyl-7-(S-alkyl-sulfonimidoyl)-xanthone-2-carboxylic acids
US4242267A · kind A · utility
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3References
5Claims
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Key dates
| Filing date | Feb 4, 1980 |
| Grant date | Dec 30, 1980 |
| Priority date | — |
| Expiry date | Feb 4, 2000 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D311/86
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A novel process for the preparation of xanthane-2-carboxylic acids of the formula ##STR1## wherein R is selected from the group consisting of hydrogen and alkyl of 1 to 9 carbon atoms and R.sub.1 is alkyl of 1 to 5 carbon atoms which possess an antiallergic activity and are particularly useful for treating asthma and asthmatic form bronchitisis of allergic origin.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.