A mixture of 4-[4-(cyclopropylsulfonyl)phenyl]-5-(tetrahydro-2H-pyran-4-yl)pent-1-en-3-one (1.84 g), 5-[(tetrahydro-2H-pyran-2-yloxy)methyl]-1,3-thiazole-2-carbaldehyde (1.32 g), 3-benzyl-5-(2-hydroxyethyl)-4-methyl-1,3-thiazol-3-ium chloride (0.14 g), triethylamine (0.32 mL), tetrahydrofuran (5 mL) and ethanol (10 mL) was stirred with heating under reflux for 2 hr. The reaction mixture was concentrated, and the residue was subjected to basic silica gel column chromatography, and the title compound (2.43 g, yield 80%) was obtained as a yellow oil from a fraction eluted with ethyl acetate-hexane (2:1, volume ratio). MS: 576 (MH+).
