[CH2:1]([O:3][C:4](=[O:21])[CH2:5][C:6]([C:19]#[N:20])([C:13]1[CH:14]=[N:15][CH:16]=[CH:17][CH:18]=1)[CH2:7][C:8](OCC)=[O:9])[CH3:2].[BH4-].[Na+].ClCCl.CO>CO.O.O.O.O.O.O.[Co](Cl)Cl>[CH2:1]([O:3][C:4](=[O:21])[CH2:5][C:6]1([C:13]2[CH:14]=[N:15][CH:16]=[CH:17][CH:18]=2)[CH2:7][C:8](=[O:9])[NH:20][CH2:19]1)[CH3:2]Combine 3-cyano-3-(pyrid-3-yl)pentanedioic acid diethyl ester (50 g, 172 mmol) and cobalt(II)chloride hexahydrate (81.8 g, 344 mmol) in methanol (500 mL). While maintaining the temperature at or below 20° C. with an ice-bath, add portionwise sodium borohydride (65.1 g, 1.72 mol). After the addition is complete, allow the reaction mixture to stand at ambient temperature. After 18 hours, evaporate the reaction mixture in vacuo to obtain a residue. Quench the reaction mixture by adding ammonium chloride and 0.5 M aqueous sodium hydroxide solution. Adjust the pH of the quenched reaction mixture to about 8 using 1 M aqueous hydrochloric acid solution. Filter through celite and extract the aqueous filtrate twice with dichloromethane. Combine the organic layers, dry over Na2SO4, filter, and concentrate in vacuo to give a residue. Chromatograph the residue on silica gel eluting with dichloromethane/methanol 10/1 to give the title compound.
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