A mixture of 5-[4-(cyclopropylsulfonyl)phenyl]-6-(tetrahydro-2H-pyran-4-yl)-1-{5-[(tetrahydro-2H-pyran-2-yloxy)methyl]-1,3-thiazol-2-yl}hexane-1,4-dione (3.35 g), 1M hydrochloric acid (6 mL) and tetrahydrofuran (10 mL) was stirred overnight at room temperature. To the reaction mixture was added saturated aqueous sodium hydrogen carbonate, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried (MgSO4) and concentrated. The obtained residue was subjected to silica gel column chromatography, and the title compound (1.83 g, yield 73%) was obtained as a colorless oil from a fraction eluted with ethyl acetate. MS: 492 (MH+).
