Imidazole → 3-[(Tert-butyldimethylsilyloxy)methyl]-6-[methyloxy[3-hydroxyquinoxalin-2-yl]]-1,2-dithiin

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Reaktionsschritte

To a stirred solution of 3-(hydroxymethyl)-6-[(tert-butyldimethylsilyloxy)methyl]-1,2-dithiin (U.S. Ser. No. 08/212,096) (200 mg, 0.688 mmol) of in 2 mL dry THF was added a solution of 3-(tert-butyldimethylsilyloxy)-2-hydroxyquinoxaline obtained from the reaction of 2,3-dihydroxyquinoxaline with tert-butyldimethylsilyl chloride and imidazole as in Example 6 (248 mg, 1.753 mmol) in 2 mL THF, followed by addition of triphenylphosphine (220 mg, 0.839 mmol). The resulting solution was cooled to 0° C., then 140 μL (155 mg, 0.890 mmol) of diethylazodicarboxylate was added, and the reaction mixture was kept at 0°-5° C. for 2 h until TLC analysis showed the reaction to be complete. For isolation of the products, the reaction mixture poured directly onto a silica gel column and eluted with ethyl acetate-hexane, 1:6, to give 3-[(tert-butyldimethylsilyloxy)methyl]-6-[methyloxy[3-hydroxyquinoxalin-2-yl]]-1,2-dithiin (104 mg, 28.2%). No product of N-alkylation was isolated; MS (+LSIMS) 549.4 (MH+).

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