反应详情

2-Nitro-6-trifluoromethyl-phenol (1.8 g) (J. Org. Chem. 1962, 27, 4660-4662) was dissolved in MeOH (20 ml) prior to the addition of 10% Pd/C (1.0 g). The reaction was placed on a Parr aparatus under hydrogen at 60 psi for 4 h. The palladium was filtered off and the solution was concentrated to give 2-amino-6-trifluoromethyl-phenol (1.1 g): 1H NMR (CD3OD, δ ppm, 300 mHz) 6.78 (m, 2H), 6.90 (d, 1H). (22b) A portion (200 mg) of the above derivative (22a) was dissolved in p-xylene prior to the addition of diethyl malonate (0.9 ml) and p-toluenesulfonic acid (22 mg). The reaction was heated to reflux with azeotropic removal of the water. After cooling to rt, the solution was concentrated. Flash chromatography of the resulting residue gave (7-trifluoromethyl-benzooxazol-2-yl)-acetic acid ethyl ester (130 mg). 1H NMR (CDCl3, δ ppm, 300 mHz) 1.30 (t, 3H), 4.09 (s, 2H), 4.25 (q, 2H), 7.41 (t, 1H), 7.60 (d, 2H), 7.90 (d, 1H). (22c) The above derivative (22b) (130 mg) was dissolved in THF (1 ml) prior to the addition of a solution of LiOH in water (1 ml). A couple drops of MeOH were added until the solution became clear. After 2 h at rt, the reaction was partially concentrated and 1N HCl was added to neutralize the reaction. This was exacted with EtOAc. The organic layer was dried, filtered and concentrated to provide (7-trifluoromethyl-benzooxazol-2-yl)-acetic acid (85 mg). 1H NMR (CD3OD, δ ppm, 300 mHz) 4.13 (s, 2H), 7.54 (t, 1H), 7.70 (d, 2H), 7.95 (d, 1H). (22d) (±)(1S*,2R*,4R*)—N4-Isopropyl-N4-methyl-2-(4-methylsulfanyl-benzenesulfonylmethyl)-cyclohexane-1,4-diamine TFA salt, from example (19g), (65 mg) was dissolved in DMF (2 ml) prior to the addition of 4-methylmorpholine (74 μl) and example (22c) (39 mg). After cooling to 0° C., BOP reagent (77 mg) was added. The resulting mixture was warmed to rt and stirred overnight before being concentrated. Reverse phase HPLC purification (gradient elution, water/acetonitrile/TFA) of the resulting residue provided the title compound (28 mg). MS found: (M+H)+=598.5

1. temperatureThe reaction was heated
2. concentrationthe solution was concentrated