反应详情

温度

0 °C

A stirred solution of 1,2-dichlorobenzene (50.0 g, 0.34 mol) in dried tetrahydrofuran (500 ml) was cooled to -65° C. under N2 and treated dropwise over 1 hour with a solution of n-butyl lithium in hexane (204 ml of 1.72 molar=0.35 mol), with the temperature held below -60° C. After stirring for a further 1 hour the pale yellow solution was treated dropwise with a solution of ethyl oxamate (19.9 g, 0.17 mol) in warm tetrahydrofuran (200 ml) with the reaction temperature held below -60° C. During this addition the reaction mixture changed from yellow through orange to Burgundy red. After stirring for a further 1 hour at -60° C. the mixture was allowed to warm to 0° C. over 2 hours, treated cautiously with water (250 ml) and acidified to pH 6 with hydrochloric acid. The yellow organic phase was separated, washed with brine (2×250 ml), dried (magnesium sulphate) and evaporated to give a yellow solid. This was slurried with ethanol (300 ml) and filtered to give crude 2,3-dichlorophenylglyoxylamide (12.0 g, 32.4%) as an off-white solid m.p. 213-214° C. (ref. m.p. 216-218° C.). Concentration of the ethanolic filtrate to 150 ml afforded a second crop (7.0 g, 18.9%) m.p. 205-206° C.

1. customheld below -60° C
2. customheld below -60° C
3. additionDuring this addition the reaction mixture
4. stirringAfter stirring for a further 1 hour at -60° C. the mixture
5. customThe yellow organic phase was separated
6. washwashed with brine (2×250 ml)
7. dry with materialdried (magnesium sulphate)
8. customevaporated
9. customto give a yellow solid
10. filtrationfiltered