To a solution of monomethyl isophthalate (226 mg, 1.26 mmol) in anhydrous N,N-dimethylformamide (8 mL) was added 1-hydroxybenzotriazole monohydrate (204 mg, 1.51 mmol), followed by 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (288 mg, 1.51 mmol) and triethylamine (0.180 mL, 1.26 mmol). The mixture was stirred at room temperature for 30 minutes followed by the addition of a solution of Example 17D (380 mg, 1.2 mmol) in anhydrous N,N-dimethylformamide (2 mL). The mixture was allowed to stir at room temperature for 16 hours, concentrated under reduced pressure. The residue was diluted with dichloromethane (20 mL) and extracted with 1 M HCl (20 mL), saturated sodium bicarbonate (20 mL) and brine (20 mL) respectively. The organic layer was separated and dried (Na2SO4), filtered and concentrated to a light yellow oily solid which was chromatographed on a Biotage 40M with ethyl acetate to provide the titled compound. MS (APCI) m/e 478 (M+H)+.
