To a mixture of N-cyclopropyl-3-fluoro-5-(4-formyl-2-(3-hydroxy-2,2-dimethylpropyl)-1-oxo-1,2-dihydroisoquinolin-6-yl)-4-methylbenzamide (Example 2c, 0.20 g) and titanium(IV) isopropoxide (2 mL) was added 1-methyl-1,4-diazepane (0.17 mL) under nitrogen. The resulting mixture was stirred at 20° C. for 2 h before adding sodium triacetoxyborohydride (0.38 g). The mixture was stirred at room temperature for 2 h. TFA (5 mL) was added and the mixture stirred at room temperature for 72 h and then evaporated to dryness. The mixture was quenched with 10% aq ammonia (5 ml) and extracted with ethyl acetate. The organic was dried (MgSO4), filtered and evaporated to afford crude product. The crude product was purified by preparative HPLC (Phenomenex Gemini column using a 95-5% gradient of aqueous 0.2% ammonia in acetonitrile as eluent) to afford the title compound (0.055 g) as a white solid.
