反应详情

2-Methoxyethyl 4-hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide (31.0 g., 0.1035 mole) was combined with 230 ml. of acetone and cooled to 10° C. Methyl iodide (21.9 g., 0.155 mole) was added, followed by the dropwise addition, over 10 minutes, of sodium hydroxide (103.5 ml. of 1 N). The cooling bath was removed and the reaction mixture allowed to slowly warm to room temperature (about 45 minutes), then heated at 35° C. for 2 hours and finally at 39°-40° C. for 16 hours. The reaction mixture was cooled to room temperature, diluted with 200 ml. of acetone, treated with activated carbon, filtered and concentrated in vacuo at 0°-5° C. to about 50 ml. The resulting slurry was filtered, and solids washed with ice-water and then dried in vacuo to yield 2-methoxyethyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide [29.26 g., 90%; m.p. 106°-107.5° C.; m/e 313; ir(KBr) 3345, 2941, 1684, 1351, 1053 cm-1 ].

1. customThe cooling bath was removed
2. temperatureheated at 35° C. for 2 hours and finally at 39°-40° C. for 16 hours
3. temperatureThe reaction mixture was cooled to room temperature
4. additiondiluted with 200 ml
5. additionof acetone, treated with activated carbon
6. filtrationfiltered
7. concentrationconcentrated in vacuo at 0°-5° C. to about 50 ml
8. filtrationThe resulting slurry was filtered
9. washsolids washed with ice-water
10. customdried in vacuo