反应详情

To a mixture of 235 g of 5,6-dihydro-2-(methylthio)-4H-1,3-thiazine and 2 g of zinc chloride at approximately 115° in a nitrogen atmosphere, 263 g of ethyl nitroacetate was added dropwise over a 1.5 hour period. The mixture was held at 110°-120°. When evolution of methyl mercaptan ceased after 45 minutes further stirring of the heated mixture, 1 g of zinc chloride was added and the mixture was stirred at about 115° for 1.25 hours. An additional 1 g of zinc chloride then was added and stirring of the mixture at about 115° was continued for 1.5 hours. The mixture then was poured into a cooled solution of 2/1 ether/isopropyl alcohol mixture. The crystallized product was collected, washed with ether and dried under reduced pressure to leave a tan solid, m.p. 100°-102°, which on recrystallization from methanol gave ethyl nitro(tetrahydro-2H-1,3-thiazin-2-ylidene)acetate (1A) as a pale yellow solid, m.p. 105°-106°.

1. additionwas added dropwise over a 1.5 hour period
2. customwas held at 110°-120°
3. additionwas added
4. stirringstirring of the mixture at about 115°
5. waitwas continued for 1.5 hours
6. customThe crystallized product was collected
7. washwashed with ether
8. customdried under reduced pressure
9. customto leave a tan solid, m.p. 100°-102°, which
10. customon recrystallization from methanol