In 490 g of tetrahydrofuran were dissolved 45 g (0.19 mol) of (3-(hydroxy)imino-3H-thiophen-2-ylidene)-(2-methylphenyl)-acetonitrile in Synthesis Example 14 and 61.8 g (0.19 mol) of 4-(4′-methylphenylsulfonyloxy)benzenesulfonyl chloride in Synthesis Example 7. To the solution cooled, 20.6 g (0.20 mol) of triethylamine was added dropwise such that the temperature might not exceed 10° C. The solution was allowed to ripen for 1 hour at room temperature, after which 150 g of water and 500 g of dichloromethane were added. The organic layer was separated, and washed with 150 g of water three times. The organic layer was concentrated in vacuum to 130 g. Methanol was added to the concentrate for recrystallization, followed by filtration and drying. There was obtained 83 g of yellow crystals. The crystals were purified by silica gel column chromatography (eluent, dichloromethane). The elute was concentrated, followed by recrystallization from methanol, filtration and drying. There was obtained 77 g of yellow crystals (yield 72%).
