0.28 ml of piperazylethanol, 273 mg of DMAP and 461 mg of dicyclohexylcarbodiimide were added to a dichloromethane solution containing 400 mg of (1S,4aS,6S,7R,7aR)-6,7-epoxy-1,4a,5,6,7,7a-hexahydro-7-methyl-1-(methylcarbamoyloxy) cyclopenta [c]-pyrane-4-carboxylic acid described in Example 1 followed by stirring for 15 hours at room temperature. The reaction mixture was then extracted with dichloromethane. After washing the organic phase with saturated aqueous sodium bicarbonate and brine, it was dried over anhydrous magnesium sulfate. After distilling off the solvent under reduced pressure, the residue was purified by silica gel chromatography to obtain a colorless amorphous substance from the dichloromethane-methanol eluate in the form of (1S,4aS,6S,7R,7aR)-6,7-epoxy-1,4a,5,6,7,7a-hexahydro-7-methyl-1-(methylcarbamoyloxy) cyclopenta [c]-pyrane-4-carboxylic acid 4-(2-hydroxyethyl) piperazylamide (276 mg, yield: 49%). The physicochemical properties of this compound are described in Table 5, Compound No. 22.
