To a stirred solution of ethyl 2-(1-(benzyloxycarbonylamino)-4-(hydroxymethyl)cyclohexyl)-5-hydroxy-6-oxo-1,6-dihydropyrimidine-4-carboxylate (1.85 g, 4.15 mmol) in THF (40 mL) cooled to 0° C. was added methanesulfonyl chloride (0.96 mmol, 12.45 mmol) and triethylamine (1.79 mL, 12.87 mmol). The mixture was allowed to warm to room temperature and stirred for 18 h. The resulting precipitate was filtered off and washed with THF. The filtrate and washings were concentrated to afford an amber oil. A solution of this oil in methanol (10 mL) was treated with K2CO3 (574 mg, 4.15 mmol) at room temperature for 3 h. The mixture was then concentrated and the residue was dissolved in ethyl acetate (200 mL), washed with 1N HCl (100 mL) followed by brine (100 mL), then dried (Na2SO4), filtered and concentrated to give 2.3 g of title compound as a yellow oil. LCMS (M+H)=602.45.
