59-67-6

71-36-3

6938-06-3

GENERAL METHOD: Nicotinic acid (0.2 mol) was dissolved in a solvent mixture of n-butanol (110 mL) and benzene (30 mL), and concentrated sulfuric acid (98%, density = 1.84) was slowly added with continuous stirring. A water separator was installed and the reaction mixture was heated to reflux and kept stirring for 8 hours. Upon completion of the reaction, excess n-butanol and benzene were removed by distillation. The residue was carefully poured into ice water (150 mL) and neutralized with saturated sodium carbonate solution to pH=7-8. The aqueous phase was extracted with isopropyl ether (3 x 100 mL). The organic phases were combined and dried with anhydrous magnesium sulfate overnight, followed by filtration. The filtrate was first removed from the isopropyl ether by distillation and then distilled under reduced pressure to give butyl 3-pyridinecarboxylate.