Methyl iodide → (3R,5R)-1-allyloxycarbonyl-3-t-butyldimethylsilyloxy-5-[1-(imidazo[5,1-b]thiazol-3-yl)-1-(methylthiocarbonyloxy)methyl]pyrrolidine

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Reaction Steps

Imidazole (2.7 mg), 0.53 ml of carbon disulfide, and 128 mg of sodium hydride are successively added to a solution of 1.28 g of (3R,5S)-1-allyloxycarbonyl-3-t-butyldimethylsilyloxy-5-[1-hydroxy-1-(imidazo[5,1-b]thiazol-3-yl)methyl]pyrrolidine (a diastereomer mixture), described in Synthesis Example 7-a), in 20 ml of dry THF under ice cooling, and the mixture is stirred at that temperature for 20 min. Methyl iodide (0.19 ml) is added dropwise to the mixed solution, and the temperature of the mixture is gradually raised and stirred at room temperature overnight. Water is added to the reaction solution, and the mixture is extracted three times with ethyl acetate. The organic layer is washed twice with saturated saline, dried over anhydrous magnesium sulfate, and filtered. The solvent is removed by evaporation under reduced pressure, and the resultant crude product is purified by column chromatography on silica gel (hexane:ethyl acetate=1:1) to give 1.31 g of (3R,5R)-1-allyloxycarbonyl-3-t-butyldimethylsilyloxy-5-[1-(imidazo[5,1-b]thiazol-3-yl)-1-(methylthiocarbonyloxy)methyl]pyrrolidine (a diastereomer mixture) as a colorless oil.

Provenance & Evidence