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|Title:||Production of 4-hydroxy-1,2-benzothiazine-3-carboxamides|
|Abstract:||A process for the synthesis of N-aryl-3,4-dihydro-2-alkyl-4-oxo-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxides by treatment of N-aryl-N'-alkyl-N'-(2'-alkoxycarbonylbenzenesulfonyl)glycineamides, useful intermediates for said process, with an alkali or alkaline earth metal hydride in a reaction-inert solvent at 50.degree.-150.degree. C., said products being antiinflammatory agents.|
|Inventor(s):||Lombardino; Joseph G. (Niantic, CT)|
|Assignee:||Pfizer, Inc. (New York, NY)|
|Filing Date:||Nov 30, 1976|
|Claims:||1. A process for the preparation of a compound of the formula: ##STR10## wherein R.sub.1 is selected from the group consisting of phenyl; monosubstituted phenyl wherein said substituent is selected from the group consisting of fluoro, chloro, methyl and methoxy; 2-thiazolyl; 4,5-dimethyl-2-thiazolyl; 2-pyridyl; 6-methyl-2-pyridyl, and 5-methyl-3-isoxazolyl; |
R.sub.2 is alkyl containing from 1 to 3 carbon atoms; and
X is a substituent selected from the group consisting of hydrogen, methyl, methoxy, fluoro, chloro and bromo, which comprises contacting a compound of the formula: ##STR11## wherein R.sub.3 is alkyl containing from 1 to 3 carbon atoms, with a metal hydride selected from the group consisting of alkali and alkaline earth metal hydrides, in a reaction-inert solvent at 50.degree.-150.degree. C.
2. The process of claim 1 wherein the metal hydride is sodium hydride.
3. The process of claim 2 wherein the solvent is tetrahydrofuran.
4. The process of claim 3 wherein X is hydrogen, and R.sub.2 and R.sub.3 are each methyl.
5. The process of claim 4 wherein R.sub.1 is phenyl.
6. The process of claim 4 wherein R.sub.1 is 2-thiazolyl.
7. The process of claim 4 wherein R.sub.1 is 6-methyl-2-pyridyl.
8. The process of claim 4 wherein R.sub.1 is 2-pyridyl.