反应详情

To a mixture of 235 g of 5,6-dihydro-2-(methylthio)-4H-1,3-thiazine (A. F. McKay et al., J. Am. Chem. Soc., 80, 3339 (1950)) and 2 g of zinc chloride at approximately 115° in a nitrogen atmosphere, 263 g of ethyl nitroacetate (S. Zen et al., Kogyo Kagaku Zosshi, 74, 70 (1971)) 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 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 (5A), as a pale yellow solid, m.p. 105°-106°.

1. customwas held at 110°-120°
2. additionwas added
3. stirringstirring of the mixture at about 115°
4. waitwas continued for 1.5 hours
5. additionThe mixture then was poured into
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