(1S,2S,3R,4R)-3-(2,3-Diamino-pyridin-4-ylamino)-bicyclo[2.2.1]hept-5-ene-2-carboxylic acid amide (50.0 mg, 0.193 mmol) and 3-dimethylamino-benzaldehyde (31.6 mg, 0.212 mmol) were combined with ammonium acetate (29.7 mg, 0.386 mmol) and heated in ethanol (2.5 mL) at 70° C. for 18 h. The reaction mixture was concentrated and chromatographed by reverse phase preparative HPLC. The desired fractions were neutralized with bicarb solution and extracted into EtOAc. The organic layer was dried over MgSO4, filtered and concentrated. This residue was triturated in ethyl ether and filtered to yield 28 mg (37%) of the title compound. mp: 200-204° C., 1H NMR (300 MHz, DMSO-d6): 13.02 (s, 1H), 7.90 (d, 1H), 7.66 (s, 1H), 7.50 (s, 1H), 7.47 (d, J=8 Hz, 1H), 7.30 (t, J=8 Hz, 1H), 7.15 (s, 1H), 6.86 (m, 1H), 6.81 (d, J=8 Hz, 1H), 6.40 (d, J=5 Hz, 1H), 6.33 (s, 2H), 2.98 (s, 6H), 2.87 (s, 1H), 2.77 (s, 1H), 2.60 (d, J=8 Hz, 1H), 2.24 (d, J=8 Hz, 1H), 1.42 (d, J=8 Hz, 1H). HPLC: 1.63 min (G method), MS: 389 (M+H).
