The title compound 6-(4-(benzo[d]thiazol-2-ylcarbamoyl)-1-methyl-1,2,3,4-tetrahydroquinoxalin-6-yl)-3-(3-phenoxypropoxy)picolinic acid (26) was prepared by the following procedure: LiOH (12 mg, 10 eq) was added to a mixture of Methyl 6-(4-(benzo[d]thiazol-2-ylcarbamoyl)-1-methyl-1,2,3,4-tetrahydroquinoxalin-6-yl)-3-(3-phenoxypropoxy)picolinate (26E) (25 mg, 0.041 mmol) in MeOH (0.5 mL) and water (0.25 mL) at rt. The mixture was heated to 55° C. for 14 hours, cooled to 0° C. and acidified with 1N HCl to pH˜4. The resulting precipitate was filtered, washed with water and dried in vacuo to provide 15 mg (61%) of the desired product 6-(4-(benzo[d]thiazol-2-ylcarbamoyl)-1-methyl-1,2,3,4-tetrahydroquinoxalin-6-yl)-3-(3-phenoxypropoxy)picolinic acid (26): 1H NMR (300 MHz, DMSO-d6) δ 8.13 (1H, bs), 7.83 (1H, d), 7.80 (1H, d), 7.65 (2H, m), 7.37 (1H, t), 7.32-7.18 (4H, m), 6.94 (3H, m), 6.79 (1H, d), 4.26 (2H, t), 4.15 (2H, t), 4.02 (2H, t), 3.41 (2H, t), 2.97 (3H, s), 2.17 (2H, t). MS (ESI(+)): m/z 596.1 (M+H).
