2,6-Lutidine → 17-Ethyl-1-hydroxy-12-[2'-(4"-(tert-butyldimethyl-silyloxy)-3"-methoxycyclohexyl)-1'-methylvinyl]-23,25-dimethoxy-13,19,21,27-tetramethyl-11,28-dioxa-4-azatricyclo[22.3.1.04,9]octacos-18-ene-2,3,10,16-tetraone

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Reaction Steps

To a solution of 17-ethyl-1-hydroxy-12-[2'-(4"-hydroxy-3"-methoxycyclohexyl)-1'-methylvinyl]-23,25 -dimethoxy-13,19,21,-27-tetramethyl-11,28-dioxa-4-azatricyclo[22.3.1.04,9 ]octacos-18-ene-2,3,10,16-tetraone (200 mg) in dry methylene chloride (3 ml) was added an excess of 2,6-lutidine (45 μl) and the mixture was stirred at room temperature. After 10 minutes, tert-butyldimethylsilyl trifluoromethane-sulfonate (64 μl) was added by syringe. After 15 minutes the reaction mixture was diluted with ethyl acetate, extracted from saturated bicarbonate, washed with brine and the organic phase dried over magnesium sulfate. Removal of solvent in vacuo and flash chromatography on silica gel (ethyl acetate: hexane (1:2)+1% methanol) gave the title compound (235 mg).

Provenance & Evidence