2-Methyl-4-Hydroxy-2H-1,2-Benzothiazine-3-Carboxylic Methylester-1,1-Dioxide

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In a manner similar to Example 6, 864 mg. (0.036 mole) of 99% sodium hydride was added over a two hour period to a solution of 2.9 g. (0.015 mole) of N-methylsaccharin and 9.8 g. (0.09 mole) of methylchloroacetate in 10 ml. of dimethylsulfoxide at 40° C. Stirring was continued at 40°-45° C. for an additional two hours, and the reaction mixture was poured into 150 ml. of 5% hydrochloric acid solution. The precipitate was filtered and dried to give 3.07 (76%) of the desired product. at 40° C the reaction mixture was poured into 150 ml The precipitate was filtered dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 2.9 g. (0.015 mole) of N-methylsaccharin and 2.63 g. (0.03 mole) of methylchloroacetate in 10 ml. of dimethylformamide at 40° C. was added over a period of two hours 864 mg. (0.036 mole) of 99% sodium hydride. Stirring was continued for two hours, maintaining a reaction temperature of 40°-50° C. The reaction mixture was quenched in 150 ml. of 5% hydrochloric acid, and the precipitated product filtered and dried, 3.41 g. (84%). maintaining a reaction temperature of 40°-50° C The reaction mixture was quenched in 150 ml of 5% hydrochloric acid, and the precipitated product filtered dried

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 9.0 g (33 mmols) of methyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate-1,1-dioxide, 4.36 g (33 mmols) of 2-amino-6-chloro-pyrazine and 1200 ml of xylene was refluxed for 24 hours in a nitrogen atmosphere. The methanol formed by the reaction was removed with the aid of a 4 Å molecular sieve arranged in a Soxhlet attachment. After cooling and standing overnight, the crystals were filtered off and recrystallized from dioxane. 7.91 g (64% of theory) of N-(6-chloro-pyrazin-2-yl)-4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide were obtained. was refluxed for 24 hours in a nitrogen atmosphere was removed with the aid of a 4 Å molecular sieve After cooling the crystals were filtered off recrystallized from dioxane

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 9.0 g (33 mmols) of methyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate-1,1-dioxide, 4.36 g (33 mmols) of 2-amino-6-chloro-pyrazine and 1200 ml of xylene was refluxed for 24 hours in a nitrogen atmosphere. The methanol formed by the reaction was removed with the aid of a 4 Å molecular sieve arranged in a Soxhlet attachment. After cooling and standing overnight, the crystals were filtered off and recrystallized from dioxane. 7.91 g (64% of theory) of N-(6-chloro-pyrazin-2-yl)-4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide were obtained. was refluxed for 24 hours in a nitrogen atmosphere was removed with the aid of a 4 Å molecular sieve After cooling the crystals were filtered off recrystallized from dioxane