[C:1]([NH:9][C@H:10]1[CH2:15][CH2:14][CH2:13][CH2:12][C@H:11]1[C:16]([OH:18])=[O:17])(=[O:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.Cl.[CH3:20]N(C)CCCN=C=NCC.C[O-].[Na+].Cl>CO.O1CCCC1.C(#N)C>[C:1]([NH:9][C@H:10]1[CH2:15][CH2:14][CH2:13][CH2:12][C@@H:11]1[C:16]([O:18][CH3:20])=[O:17])(=[O:8])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1A mixture of (1R,2S)-2-(benzoylamino)cyclohexanecarboxylic acid (2.47 g, 10 mmol), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (2.30 g, 12 mmol), acetonitrile (25 ml) and tetrahydrofuran (25 ml) was stirred at room temperature for 30 min. The reaction mixture was concentrated under reduced pressure, methanol (25 ml) was added, and the mixture was stirred at 60° C. for 3 hrs. The reaction mixture was concentrated under reduced pressure, dil. hydrochloric acid was added, and the mixture was extracted with ethyl acetate. The extract was washed with aqueous sodium hydrogen carbonate solution, then with saturated brine and dried (over anhydrous MgSO4). The solvent was evaporated under reduced pressure. 28% Sodium methoxide in methanol solution (1.93 g, 10 mmol) and methanol (30 ml) were added to the residue and the mixture was heated under reflux for 5 hrs. 1N Hydrochloric acid (11 ml) was added under ice-cooling, and methanol was evaporated under reduced pressure. Aqueous sodium hydrogen carbonate solution was added to the obtained residue, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried (over anhydrous MgSO4), and the solvent was evaporated under reduced pressure. The obtained solid was collected by filtration and washed with diisopropy ether to give methyl (1S,2S)-2-(benzoylamino)cyclohexanecarboxylate (1.33 g, 51%) as a colorless powder.
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