Process for the preparation of 3,4-dihydro-2-methyl-4-oxo-2h-1,2-benzothiazine-3-carboxylic acid-1,1-dioxide and its use as an intermediate
CA 1077934 A · Owner: Pfizer Inc. · Inventors: Hammen, Philip D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Process for production of 3,4-dihydro-2-methyl-4-oxo- 2H-1,2-benzothiazine-3-carboxylic acid-1,1-dioxide by hydrolysis in the presence of hydroxide ions, of an alkyl or aralkyl ester thereof followed by precipitation of the acid at pH below 6.0 and its use as an intermediate for the production of N-(2-pyridyl)- 3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxamide- 1,1-dioxide and the analogous N-(2-thiazolyl)-compound effective, antiinflammatory agents.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted May 20, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 20, 1997.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.