A solution of 2 ml of acetonitrile-1 ml of methanol containing 100 mg of (R)-3-chloroacetyl-4-cyanothiazolidine (the compound of Reference Example 2 mentioned below) and 372 mg of N-(5-nitro-2-pyridyl)-trans-1,4-cyclohexanediamine was stirred at room temperature for 15 hours. Water was added to the reaction mixture and the mixture was extracted with chloroform. After the extract was dried over anhydrous sodium sulfate, the solvent was removed under reduced pressure. The residue was purified by diol column chromatography (solvent: 0 to 5% methanol-chloroform) to obtain an oily product. The oily product was dissolved in 0.5 ml of ethyl acetate-0.5 ml of chloroform, and 1.0 ml of 2N hydrochloric acid-ether was added thereto, followed by 2 ml of ether. Precipitates were collected by filtration and washed with ether to obtain 173 mg of (R)-4-cyano-3-[trans-4-(5-nitro-2-pyridylamino)cyclohexylamino]acetylthiazolidine.dihydrochloride (Example 4-1 in Table 4).
