反应详情

温度

50 °C

1-Cyano-4-(N,N-dimethylamino)-1-methoxycarbonyl-3-methyl-1,3-butadiene (33.6 g, 0.173 mol) prepared in a manner analogous to that described in Example 1(i) above was suspended in 1,2-dichloroethane (330 ml) and heated to 50° C. with stirring whereupon a steady stream of hydrogen chloride was passed through the mixture. After 21/4 hours, the clear solution was concentrated. The residue was dissolved in water and this solution was extracted with dichloromethane (3×100 ml). The pooled organic layers were dried with sodium sulphate and evaporated. Crystallisation of the residue from petrol yielded colourless crystals of 2-chloro-5-methylnicotinic acid methyl ester (30.0g, 93.4% of theoretical yield) with m.pt. 31° C.-33° C.

1. concentrationAfter 21/4 hours, the clear solution was concentrated
2. dissolutionThe residue was dissolved in water
3. extractionthis solution was extracted with dichloromethane (3×100 ml)
4. dry with materialThe pooled organic layers were dried with sodium sulphate
5. customevaporated
6. customCrystallisation of the residue from petrol yielded colourless crystals of 2-chloro-5-methylnicotinic acid methyl ester (30.0g, 93.4% of theoretical yield) with m.pt. 31° C.-33° C.