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Under an argon atmosphere, 5-(4-acetoxyphenyl)-2-amino-3-benzylpyrazine (c-19) (681 mg, 2.13 mmol) was dissolved in anhydrous dichloromethane (40 mL), and to this was added triethylamine (1.20 mL, 8.53 mmol), and cooled to 0° C. To this was added 4-iodobenzylsulfonyl chloride (prepared by the method described in Liu, S. et al., Org. Lett., 3, 1571-1574 (2001)) (2.70 g, 8.53 mmol), and heated to reflux for 26 h after warming to room temperature. After cooling to room temperature, to this were added 2 M hydrochloric acid and dichloromethane and after separating the aqueous layer and organic layer, the organic layer was washed once with water and once with saturated brine, and dried over anhydrous sodium sulfate. After removing anhydrous sodium sulfate by filtration, the filtrate was concentrated under reduced pressure with a rotary evaporator. The residue was purified by silica gel column chromatography (100 g, n-hexane/ethyl acetate=4/1), to the obtained product was added dichloromethane, and filtered to remove insolubles. After this procedure was repeated 5 times, the filtrate was concentrated under reduced pressure with a rotary evaporator. The residue was recrystallized from ethyl acetate to give 5-(4-acetoxyphenyl)-3-benzyl-2-bis(4-iodobenzylsulfonyl)aminopyrazine (c-46) as a colorless solid (597 mg, 31.8%). Rf=0.21 (n-hexane/ethyl acetate=4/1). Mp. 166-167° C. 1H NMR. (400 MHz, DMSO-d6) δ 2.30 (s, 3H), 3.89 (s, 2H), 5.00 (d, 2H, J=13.6 Hz), 5.19 (d, 2H, J=13.6 Hz), 7.11-7.17 (AA′BB′, 2H), 7.19-7.34 (m, 9H), 7.78-7.83 (AA′BB′, 4H), 8.07-8.15 (AA′BB′, 2H), 9.19 (s, 1H). 13C NMR (67.8 MHz, DMSO-d6) δ 20.9, 37.5, 60.5 (2C), 96.3, 126.4, 126.5 (2C), 128.1 (2C), 128.5 (2C), 129.5 (2C), 132.0, 133.6 (4C), 137.4, 137.7 (4C), 139.2, 140.9, 151.2, 152.5, 155.5, 168.9. IR (KBr, cm−1) 519, 575, 627, 704, 775, 835, 912, 1013, 1057, 1159, 1200, 1254, 1356, 1377, 1483, 1601, 1757. Anal. Calcd. For C33H27I2N3O6S2: C, 45.06; H, 3.09; N, 4.78. Found: C, 45.18; H, 3.24; N, 4.78.

1. customprepared by the method
2. temperature, 3, 1571-1574 (2001)) (2.70 g, 8.53 mmol), and heated
3. temperatureto reflux for 26 h
4. temperatureafter warming to room temperature
5. temperatureAfter cooling to room temperature
6. customafter separating the aqueous layer and organic layer
7. washthe organic layer was washed once with water and once with saturated brine
8. dry with materialdried over anhydrous sodium sulfate
9. customAfter removing anhydrous sodium sulfate
10. filtrationby filtration
11. concentrationthe filtrate was concentrated under reduced pressure with a rotary evaporator
12. customThe residue was purified by silica gel column chromatography (100 g, n-hexane/ethyl acetate=4/1), to the obtained product
13. additionwas added dichloromethane
14. filtrationfiltered
15. customto remove insolubles
16. concentrationthe filtrate was concentrated under reduced pressure with a rotary evaporator
17. customThe residue was recrystallized from ethyl acetate