Process for the preparation of 4-hydroxy-2-methyl-N-2-pyridyl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide
US4474956A · kind A · utility
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4References
10Claims
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Key dates
| Filing date | Jun 29, 1983 |
| Grant date | Oct 2, 1984 |
| Priority date | — |
| Expiry date | Jun 29, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D417/12
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
In the preparation of 4-hydroxy-2-methyl-N-2-pyridyl-2H-benzothiazine-3-carboxamide 1,1-dioxide by reacting the corresponding 3-methoxycarbonyl compound with 2-aminopyridine, a dramatic increase in the yield is obtained if the reaction is carried out in the presence of 0.1 to 1.5 mole equivalent (based on the 3-methoxycarbonyl compound) of an alkyl- or arylsulfonic acid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.