Carbon Dioxide → 1-Methoxy-2-naphthoic acid

Participants

Reaction Conditions

Reaction Steps

Reference: J. Organomet. Chem., 20 (1969) p. 251-252. n-BuLi (208.60 mmol, 83.44 ml of a 2.5 M solution in hexane, Aldrich) was stirred under argon in 42 ml of dry cyclohexane. This solution was cooled to 0° C. and treated dropwise (10 min.) with distilled tetramethylethylenediamine (TMEDA) (208.6 mmol, 24.24 g, 31.48 ml). The resulting slurry was stirred at 0° C. for 30 minutes, then treated dropwise (20 minutes) with a solution of 1-methoxynaphthalene (208.60 mmol, 33 g, 30.28 ml) (Aldrich Chem. Co., used without further purification) in 84 ml of dry cyclohexane. The resulting bright red homogeneous reaction mixture was warmed to room temperature and stirred for 2 hours. The reaction mixture was cooled to 0° C. and added portionwise over 30 minutes via cannula to a -78° C. solution of dry Et2O (250 ml) saturated with CO2 (g) (CO2 pellets sublimed through drying tube containing SiO2, bubbled into dry Et2O at -78° C.). The resulting white slurry was warmed to ~0° over 45 minutes and then treated with 450 ml of 5% HCl (aqueous). The Et2O layer was separated and the aqueous layer extracted three times with Et2O. The organic extracts were combined and extracted with 3×150 ml saturated NaHCO3 (aqueous). The aqueous layer was filtered through a sintered glass funnel to remove insolubles and the filtrate was cooled to 0° C. and acidified slowly with concentrated HCl until pH=1. The resulting precipitate was filtered, azeotroped with 2× 150 ml of toluene, dried under high vacuum at 50° C. for 5 hours to afford 32.52 g (0.161 mol, 77% yield) of the 1-methoxy-2-naphthalene carboxylic acid as an off-white powder, m.p. 118-121.5° C.

Provenance & Evidence