Acetic Acid → N,N'-Bis(2-methylphenyl)ethanimidamide

Participants

Reaction Steps

According to literature ((Taylor, E. C. et al., J. Org. Chem. 28:1108 (1963)), a solution of o-toluidine (4.28 g, 40.0 mmol) and triethyl orthoacetate (3.24 g, 290 mmol) in acetic acid (1 ml) was heated to reflux for 2 h. Volatile compounds were distilled off (120°-140°, 20 mm) and the solid residue was extracted with ether (total of 50 ml) in presence of 1N solution of Na2CO3 in water (100 ml). Two fold recrystallization from hexane-5% toluene gave white but still impure amidine (1.85 g, 38%); Mp 65°-68° (Lit (Taylor et al., supra) 70°, Lit (Barluenga, J. et al., Perkin 1 2732 (1980) 134°-135°). On chromatography with hexanes-ether 2:1 some unreacted o-toluidine was removed as the least polar fraction (TLC ether 0.75). Intermediate fractions contained colorless N-tolyl acetimidate. Almost pure amidine (TLC ether 0.46) was eluted with hexanes-ether 1:1. This compound was further purified by chromatography with THF-hexanes 1:1 then 1:0 and filtration of the eluents through celite for the removal of turbid matter. The addition of HCl gas saturated ether (5 ml) to a solution of the amidine (313 mg, 1.31 mmol) in ether (10 ml) gave the new hygroscopic, hydrochloride of the title compound (318 mg, 88%), Mp 237°-239°.

Provenance & Evidence