反应详情

温度

-60 °C

n-Butyl chloride (55.5 g, 0.6 mol) was added dropwise to a stirred suspension of lithium slices (8.30 g, 1.2 mol) in dried ether (300 ml) under N2 so as to maintain gentle reflux. After heating under reflux for a further 33/4 hours the mixture was cooled to room temperature and stirred overnight. (Previous analyses indicate that this procedure affords a 66% yield of butyl lithium (≡0.4 mol). The mixture was then cooled to -60° C. and held at this temperature during the following operations. Dried tetrahydrofuran (400 ml) was added, then a solution of 1,2-dichlorobenzene (58.8 g, 0.4 mol) in dried tetrahydrofuran (300 ml) was added dropwise over 40 mins. After stirring the mixture for 1 hour a solution of ethyl oxamate 23.4 g, 0.2 mol) in warm tetrahydrofuran (300 ml) was added dropwise over 1 hour and the mixture stirred for a further 1 hour at -60° C. After allowing to warm to 0° C., water (300 ml) was added cautiously and the mixture acidified to pH 6 within hydrochloric acid. The yellow organic phase was separated, washed with brine (2×300 ml), dried (magnesium sulphate) and evaporated to give a pale yellow solid. This was slurried with ethanol (250 ml), filtered and dried to give crude 2,3-dichlorophenylglyoxylamide (22.5 g, 52%) m.p. 214-215° C. (ref. 215-218° C.).

1. additionwas added dropwise over 1 hour
2. temperatureto warm to 0° C.
3. customThe yellow organic phase was separated
4. washwashed with brine (2×300 ml)
5. dry with materialdried (magnesium sulphate)
6. customevaporated
7. customto give a pale yellow solid
8. filtrationfiltered
9. customdried