反应详情

17.85 g (90.98 mmol) of 4-methoxybenzyl carbazate was dissolved in 50 mL of CH2Cl2 in a 250 mL flask and then cooled in ice water. 21.42 g (155 mmol) of potassium carbonate dissolved in 80 mL of water was added. While the reaction mixture was being stirred in the ice bath, 17.0 g (79.95 mmol) of 5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl chloride in 60 mL of CH2Cl2 were slowly added. The reaction mixture was stirred at room temperature overnight and then transferred to a separatory funnel with 200 mL of CH2Cl2 and 200 mL of H2O. After shaking, a floating white precipitate was filtered off, washed with water, dried in a vacuum oven to give 29.1 g of N′-(5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)hydrazinecarboxylic acid 4-methoxy-benzyl ester. The CH2Cl2 solution was dried and concentrated to give 5.19 g of a residue consisting of the original acid chloride, 4-methoxybenzyl carbazate, and some product. TLC Rf=0.38 (streak 1:1 ethyl acetate:hexane). 1H NMR (CDCl3, 300 MHz) δ (ppm): 7.4-6.7 (m, 6H), 5.139 (s 2H), 4.279 (s 4H), 3.81 (s, 3H), 2.303 (s, 3H).

1. additionwas added
2. additionwere slowly added
3. stirringAfter shaking
4. filtrationa floating white precipitate was filtered off
5. washwashed with water
6. customdried in a vacuum oven