Triethylamine → (1S,4aS,7aR)-7-(chloromethyl)-1-(methylcarbamoyloxy)-1,4a,5,7a-tetrahydrocyclopenta [c] pyrane-4-carboxylic acid methylester

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Reaction Steps

2.0 g of (1S,4aS,6S,7R,7aR)-6,7-epoxy-7 -(hydroxymethyl)-1-(methylcarbamoyloxy)-1,4a,5,6,7,7a-hexahydrocyclopenta [c] pyrane-4-carboxylic acid methylester described in Example 19 were dissolved in dichloromethane followed by addition of 2.5 ml of triethylamine and 1.4 ml of methanesulfonylchloride while stirring and cooling with ice. After stirring for 12 hours at the same temperature, the reaction mixture was extracted with ethyl-acetate. After washing the organic phase with saturated aqueous sodium bicarbonate and brine, it was dried over magnesium sulfate. After distilling off the solvent under reduced pressure, the residue was purified by silica gel chromatography to obtain a pale yellow oil from the hexane-ether eluate in the form of (1S,4aS,7aR)-7-(chloromethyl)-1-(methylcarbamoyloxy )-1,4a,5,7a-tetrahydrocyclopenta [c] pyrane-4-carboxylic acid methylester (770 mg, yield: 24%). The physicochemical properties of this compound are described below.

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