反应详情

温度

60 °C

0.90 mol of methanol-free sodium methylate was prepared by dissolving 20.7 gm (0.90 gm-atom) of sodium in 350 ml of absolute methanol, subsequently distilling off the alcohol, and repeated azeotropic distillation with xylene. After addition of 9.15 gm (0.30 mol) of 3-oxo-naphth[2,1-d]isothiazoline-2-acetic acid methyl ester-1,1-dioxide, 250 ml of anhydrous tert.butanol were added. The reaction mixture was slowly heated to 60° C, kept at 60°-65° C for 11/4 hours, and subsequently refluxed for 1 hour. The mixture was allowed to cool, was then decomposed with ice and adjusted to a pH-value of 3-4 with concentrated hydrochloric acid. The solid product which formed was suction-filtered off, washed with water and dried, yielding 72.0 gm (78% of theroy) of 4-hydroxy-2H-naphtho[2,1-e]-1,2-thiazine-3-carboxylic acid methyl ester-1,1 -dioxide, m.p. 218°-220° C (after recrystallizing twice from ethylene chloride).

1. distillationsubsequently distilling off the alcohol
2. distillationdistillation with xylene
3. additionwere added
4. customkept at 60°-65° C for 11
5. custom4 hours
6. temperaturesubsequently refluxed for 1 hour
7. temperatureto cool
8. customThe solid product which formed
9. filtrationwas suction-filtered off
10. washwashed with water
11. customdried