4-Hydroxy-3-(3-isoxazolylcarbamoyl)-2H-1,2-benzothiazine 1,1-dioxides and process for their production

Abstract

Compounds having the following structural formula are disclosed: ##STR1## wherein R 1 is hydrogen or methyl and R 2 , and R 3 are hydrogen or alkyl. These compounds are useful as anti-inflammatory agents, antipyretics, analgesics.

We claim:  .[.1. A compound of the formula: ##STR10## wherein R 1  is hydrogen or methyl and R 2 , and R 3  are hydrogen or alkyl having 1 to 7 carbon atoms, or its corresponding alkali 
     
        metal, akaline earth and amine salts..].  .[.2.  A compound according to claim 1 which is 4-Hydroxy-3-(5-methyl-3-isoxazolylcarbamoyl)-2-methyl-2H-1,2-benzothiazine 1,1-Dioxide..].  .[.3. A compound according to claim 1 which is 4-Hydroxy-3-(3-isoxazolylcarbamoyl)-2-methyl-2H-1,2-benzothiazine 1,1-Dioxide..].  .[.4. A compound according to claim 1 which is 4-Hydroxy-3-(5-methyl-3-isoxazolylcarbamoyl)-2H-1,2-benzothiazine 1,1-Dioxide..].  pg,5  .[.5. A process for production of the compound of claim 1 which comprises refluxing together a compound of Structure II: ##STR11## in which R 4  is lower alkyl with a compound of Structure III: ##STR12## in an inert solvent in the presence of a molecular sieve adapted to remove 
     
     
        the by-product alcohol formed..].  .[.6.  A process for the production of the compound of claim 2 which comprises treating a compound of the formula: ##STR13## with sodium hydride in dimethylformamide, treating the resulting anion with methyl iodide; adding water to the reaction mixture; and recovering 
     
     
        compound I as a precipitate..]. .Iadd. 7.  A process for the production of a compound of the formula I: ##STR14## wherein R 1  is hydrogen or methyl and R 2  and R 3  are hydrogen or alkyl having 1 to 7 carbon atoms or its corresponding alkali metal, alkaline earth and amine salts; which comprises refluxing together a compound of the formula II: ##STR15## in which R 4  is lower alkyl with a compound of the formula III: ##STR16## in an inert solvent in the presence of a molecular sieve adapted to remove 
     
     
        the by-product alcohol formed. .Iaddend..Iadd. 8.  A process for the production of 4-hydroxy-3-(5-methyl-3-isoxazolylcarbamoyl)-2-methyl-2H-1,2-benzothiazine 1,1-dioxide which comprises treating a compound of the formula IV: ##STR17## with sodium hydride in dimethylformamide, treating the resulting anion with methyl iodide; adding water to the reaction mixture; and recovering 4-hydroxy-3-(5-methyl-3-isoxazolylcarbamoyl)-2-methyl-2H-1,2-benzothiazine 1,1-dioxide as a precipitate. .Iaddend.