Benzamidine → 6-(2-methyl-1H-imidazol-1-yl)-2-phenyl-quinazoline

Participants

Reaction Steps

4-(2-methyl-1H-imidazol-1-yl)-2-aminomethylaniline (2.0 g, 10 mmol) and methyl benzimidate hydrochloride (3.5 g, 20 mmol; RN: 5873-90-5, Aldrich) were dissolved in methanol (50 mL), the resulting mixture was heated at reflux for 2 hours, during this time the aminomethyl-derivative was converted into the corresponding benzamidine. After that, the methanol was evaporated and the residue taken up with glacial acetic acid (50 mL), the reaction mixture was heated at reflux for 1.5 hours. After cooling at r.t. the reaction mixture was diluted with toluene (50 mL) and evaporated. The residue was taken up with AcOEt (400 mL), washed with aq. ammonia, with water, then dried and concentrated. The obtained oily residue was dissolved in DCM (400 mL) and MnO2 (6.0 g, 70 mmol) was added at r.t., in three portions, over 2 hours. The resulting suspension was stirred at r.t. for 24 hrs, then filtered over celite and the cake was rinsed with DCM. The combined filtrate and washings were concentrated and the residue chromatographed over silica gel (DCM/MeOH/NH3, 85:25.2) the appropriate combined fractions were evaporated and the residue taken up with ethyl ether, heated at reflux for 5 minutes then cooled at 25° C. to crystallize the titled product as slightly brown powder (2.0 g; yield: 74%). C18H14N4, MW: 286.34; MS: m/z 287 (M+H); 1H-NMR (200 MHz, d6-DMSO) ppm: 2.40 (s, 1H), 7.0 (s, 1H), 7.40 (s, 1H), 7.60 (m, 3H), 8.10-8.30 (m, 3H), 8.60 (m, 2H), 9.80 (s, 1H).

Provenance & Evidence