反应 #2028873

反应方程式

3,5-fluoro-4-methoxyacetophenone

3,5-difluoro-4-methoxyacetophenone

dimethyl oxalate

sodium methoxide

→

methyl 4-(3,5-difluoro-4-methoxyphenyl)-2,4-dioxo-butanoate

溶剂

methanol

methylene chloride

反应条件

后处理

1. 1
   其他The crude reaction
2. 2
   洗涤washed with potassium bisulfate (0.1N solution), brine
3. 3
   干燥dried over MgSO4
4. 4
   过滤filtered
5. 5
   浓缩concentrated in vacuo

实验过程

To a stirred solution of 3,5-fluoro-4-methoxyacetophenone from Step 1 (6.46 g, 34.70 mmol) and dimethyl oxalate (6.15 g, 52.05 mmol) in methanol (80 mL), was added sodium methoxide solution (13.4 mL of 25% solution, 58.99 mmol) in one portion and the reaction stirred overnight. The crude reaction was diluted with methylene chloride, washed with potassium bisulfate (0.1N solution), brine, dried over MgSO4, filtered, and concentrated in vacuo yielding methyl 4-(3,5-difluoro-4-methoxyphenyl)-2,4-dioxo-butanoate as an off white crystalline solid which was used as is. A mixture of 4-(3,5-difluoro-4-methoxyphenyl)-2,4-dioxo-butanoate and 4-sulfonamidophenylhydrazine hydrochloride salt (7.76 g, 34.70 mmol) dissolved in methanol was warmed to reflux for 9 hours. Upon allowing the clear reaction to cool to room temperature, a crystalline precipitate formed which was collected by vacuum filtration yielding 5.45 g, (37% based upon the 3,5-difluoro-4-methoxyacetophenone) of methyl 1-(4-aminosulfonylphenyl)-5-(3,5-difluoro-4-methoxyphenyl)-1-H-pyrazole-3-carboxylate as an off-white solid: mp 185°-190° C.; 1H NMR (CDCl3/300 mHz) 7.95 (d, J=8.86, 2H), 7.49 (d, J=8.86, 2H), 7.02 (s, 1H), 6.77 (m, 2H), 4.99 (s, 2H, 4.04 (s, 3H), 3.98 (s, 3H); 19F NMR (CDCl3/300 mHz) −126.66. Anal. Calc'd for C17H13F2N3O3S: C, 51.06; H, 3.57; N, 9.92. Found: C, 51.06; H, 3.54, N, 9.99.

来源