Warner-lambert Company

Arthur C Fabian

Harold Zinnes

John Shavel, Jr

Jerome D Genzer

Charles Francis Kasulanis

Paul C Unangst

Richard E Brown

Frank Fontsere

This invention relates to a novel process for preparing a group of novel substituted indolopyrones.

Process for the preparation of indolopyrones

This invention relates to a process for the preparation of 1-{[5-(4-hydroxy-2H-1,2-benzothiazin-3-yl)-1,2,4-oxadiazol-3-yl]methyl}eth anone S,S-dioxide (III), a novel intermediate useful in the preparation of the known anti-inflammatory agent, 4-hydroxy-3-(5-methyl-3-isoxazolylcarbamoyl)-2-methyl-2H-1,2-benzothiazine 1,1-dioxide (IV). According to the process of this invention, the saccharin compound, 2,3-dihydro-N-(5-methyl-3-isoxazolyl)-3-oxo-1,2-benzisothiazole-2-acetamid e 1,1-dioxide (I) is reacted with an alkali metal alkoxide of a lower alcohol in an inert solvent at temperatures below 30.degree. C. to form the benzenesulfonylglycineamide, alkyl 2-{[({[(5-methyl-3-isoxazolyl)amino]carbonyl}methyl)amino]sulfonyl}benzoat e (II), which is ring closed and rearranged by reaction with an alkali metal alkoxide of a lower alcohol in an inert solvent at temperatures of from 60.degree. to 70.degree. C. to form the desired oxadiazole compound III.

Composition containing alkyl

A novel process for preparing 4-hydroxy-3-(5-methyl-3-isoxazolylcarbamoyl)-2-methyl-2H-1,2-benzothiazine 1,1-dioxide (I), starting with 3-amino-5-methylisoxazole (II) is disclosed. Compound I exhibits anti-inflammatory properties and is useful for treating inflammation. In the process of the invention an intermediate obtained, 2,3-dihydro-N-(5-methyl-3-isoxazolyl)-3-oxo-1,2-benzisothiazole-2-acetamid e 1,1-dioxide (IV) undergoes rearrangement to provide 1-{[5-(4-hydroxy-2H-1,2-benzothiazin-3-yl)-1,2,4-oxadiazol-3-yl]methyl}eth anone S,S-dioxide (V), which is methylated, according to conventional procedures. The methylated intermediate VI, upon further treatment, undergoes a second rearrangement to obtain the desired anti-inflammatory compound I.

Intermediate composition

A novel process for preparing 4-hydroxy-3-(5-methyl-3-isoxazolylcarbamoyl)-2-methyl-2H-1,2-benzothiazine 1,1-dioxide (I), starting with 3-amino-5-methylisoxazole (II) is disclosed. Compound I exhibits anti-inflammatory properties and is useful for treating inflammation. In the process of the invention an intermediate obtained, 2,3-dihydro-N-(5-methyl-3-isoxazolyl)-3-oxo-1,2-benzisothiazole-2-actamide 1,1-dioxide (IV) undergoes rearrangement to provide 1-{[5-(4-hydroxy-2H-1,2-benzothiazin-3-yl)-1,2,4-oxadiazol-3-yl]methyl}eth anone, S,S-dioxide (V), which is methylated, according to conventional procedures. The methylated intermediate VI, upon further treatment, undergoes a second rearrangement to obtain the desired anti-inflammatory compound I.

2,3-Dihydro-N-(5-methyl-3-isoxazolyl)-3-oxo-1,2-

Process for the preparation of

This invention relates to a process for the preparation of 1-{[5-(4-hydroxy-2H-1,2-benzothiazin-3-yl)-1,2,4-oxadiazol-3-yl]methyl}eth anone S,S-dioxide (III), a novel intermediate useful in the preparation of the known anti-inflammatory agent, 4-hydroxy-3-(5-methyl-3-isoxazolylcarbamoyl)-2-methyl-2H-1,2-benzothiazine 1,1-dioxide (IV). According to the process of this invention, the saccharin compound, 2,3-dihydro-N-(5-methyl-3-isoxazolyl)-3-oxo-1,2-benzisothiazole-2-acetamid e 1,1-dioxide (I) is reacted with an alkali metal alkoxide of a lower alcohol in an inert solvent at temperatures below 30.degree. C. to form the benzenesulfonylglycineamide, alkyl 2-{[({[(5-methyl-3-isoxazolyl)amino]carbonyl}methyl)amino]sulfonyl}benzoat e (II), which is ring closed and rearranged by reaction with an alkali metal alkoxide of a lower alcohol in an inert solvent at temperatures of from 60.degree. C. to 70.degree. C. to form the desired oxadiazole compound III.

A novel process for preparing 4-hydroxy-3-(5-methyl-3-isoxazolylcarbamoyl)-2-methyl-2H-1,2-benzothiazine 1,1-dioxide (I), starting with 3-amino-5-methylisoxazole (II) is disclosed. Compound I exhibits anti-inflammatory properties and is useful for treating inflammation. In the process of the invention an intermediate obtained, 2,3-dihydro-N-(5-methyl-3-isoxazolyl)-3-oxo-1,2-benzisothiazole-2-acetamid e 1,1-dioxide (IV) undergoes rearrangement to provide 1-{[5-(4-hydroxy-2H-1,2-benzothiazin-3-yl)-1,2,4-oxadiazol-3-yl]methyl}eth anone S,S-dioxide (V), which is methylated, according to conventional procedures. The methylated intermediates VI, upon further treatment, undergoes a second rearrangement to obtain the desired anti-inflammatory compound I.

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Flanders, NJ, United States of America

Arthur C Fabian