2,6-Lutidine → 4-Chloro-2,6-bis-trifluoromethyl-nicotinic acid ethyl ester

Participants

Reaction Steps

A 500 ml round bottom flask equipped with nitrogen inlet and magnetic stirrer is charged with 40 g (0.132 mol) of product from Example 2 and 24.97 g (0.233 mol) of 2,6-lutidine. To this is slowly added (exothermic) 185 ml (1.98 mol) of phosphorous oxychloride. The flask is fitted with a condenser and the mixture is heated to reflux. After refluxing for 18 hours the material is cooled, concentrated, and the mixture was poured into 150 g of ice slowly. The ice mixture was then poured into 200 ml of 10% HCl (aqueous) and extracted twice with ether. The combined ether layers were washed with 10% NaOH (aqueous), dried (MgSO4), and concentrated in vacuo affording a black oil. The residue was kugelrohr distilled at 67 Pa. The earlier fraction (pot temperature 50° C.) was discarded. The later fraction (pot temperature 85° C.) afforded 25.15 g (60%) of product, nD25 1.4185. Anal. Calc'd. for C10H6Cl1F6N1O2 : C, 37.35; H, 1.88; N, 4.36. Found: C, 37.51; H, 1.74; N, 4.23.

Provenance & Evidence