反应详情

2.8 g of triethylamine and 2.6 g of chloroformic acid methyl ester are added, while stirring and cooling with ice, to 6.1 g of 2-butoxy-5-chloro-6-methyl-nicotinic acid (melting point 95°-97° C., prepared by chlorinating 2-butoxy-6-methyl-nicotinic acid in dilute glacial acetic acid) in 75 ml of acetone. The mixture is stirred for a further 15 minutes and then added, while stirring, to 25 ml of a 1-molar solution of 4-(2-amino-ethyl)-benzoic acid-sodium, additionally containing 0.025 mol of sodium acetate and to which 25 ml of acetone has been added. Stirring of the mixture is continued for 2 hours at room temperature, the acetone is removed under reduced pressure, the remaining aqueous solution is acidified, the precipitated reaction product is filtered off with suction, reprecipitated from ammonia and recrystallized from dilute methanol or ethyl acetate. The 4-(2-<2-butoxy-5-chloro-6-methyl-nicotinamido>-ethyl)-benzoic acid obtained melts at 148°-150° C.

1. stirringThe mixture is stirred for a further 15 minutes
2. additionadded
3. stirringStirring of the mixture
4. customthe acetone is removed under reduced pressure
5. customthe precipitated reaction product
6. filtrationis filtered off with suction
7. customreprecipitated from ammonia
8. customrecrystallized from dilute methanol or ethyl acetate