反応 #52573

反応方程式

sodium methanolate

4-methylene-3-oxabicyclo[3.2.1]octan-2-one

2,3-dichloro-4-methanesulfonylbenzoyl chloride

oxalyl chloride

→

2,3-Dichloro-4-methanesulfonylbenzoic acid 4-oxobicyclo[3.2.1]oct-2-en-2-yl ester

溶媒

toluene

dimethylformamide

methanol

toluene

toluene acetonitrile

反応条件

後処理

1. 1
   その他removed by distillation
2. 2
   その他With removal of methanol
3. 3
   workup.DISTILLATIONby distillation
4. 4
   workup.ADDITIONare then added dropwise
5. 5
   workup.ADDITIONis introduced
6. 6
   workup.STIRRINGAfter stirring briefly
7. 7
   抽出extraction

実験手順

3.6 g of a 30% sodium methanolate solution (0.022 mol) are heated to a column head temperature of 108° C. in a mixture of 19 ml of toluene and 1 ml of dimethylformamide, methanol being removed by distillation. With removal of methanol by distillation being continued, 2.76 g (0.02 mol) of 4-methylene-3-oxabicyclo[3.2.1]octan-2-one dissolved in 3 ml of toluene are then added dropwise. After stirring for one hour, the mixture is cooled to a temperature of 20° C. and, while controlling the temperature, a solution in 1:1 toluene/acetonitrile of 6.32 g (0.022 mol) of 2,3-dichloro-4-methanesulfonylbenzoyl chloride freshly prepared with oxalyl chloride is introduced. After stirring briefly, extraction is carried out with a small amount of ethyl acetate against a slightly alkaline-aqueous solution at pH 10. 2,3-Dichloro-4-methanesulfonylbenzoic acid 4-oxobicyclo[3.2.1]oct-2-en-2-yl ester is obtained in the form of an amorphous crystallisate in a yield of 5.5 g (71%). 1H-NMR (DMSO-D6): 8.19 ppm, 2H; 5.85 ppm, s, 1H; 3.48 ppm, s, 3H; 3.07 ppm, m, 1H; 2.84 ppm, m, 1 H; 1.9-2.2 ppm, 4H; 1.7 ppm, 2H.

出典