Cl.[CH2:2]([N:4]([CH2:9][C:10]1[C:15]([N+:16]([O-])=O)=[CH:14][CH:13]=[C:12]([Cl:19])[C:11]=1[Cl:20])[CH2:5][C:6]([OH:8])=[O:7])[CH3:3]>O.C(O)C.[Pt]>[CH2:2]([N:4]([CH2:9][C:10]1[C:15]([NH2:16])=[CH:14][CH:13]=[C:12]([Cl:19])[C:11]=1[Cl:20])[CH2:5][C:6]([OH:8])=[O:7])[CH3:3]A solution of 0.344 g of ethyl N-(2,3-dichloro-6-nitrobenzyl)glycine hydrochloride (compound VI) in 1.5 mL of water and 1.5 mL ethanol (with 5% isopropanol) was stirred and 5% sulfided platinum on carbon under hydrogen (50 to 100 psi) for 16 hours. The catalyst was removed by filtration. The filtrate concentrated, diluted with water and toluene, and basified (aqueous sodium hydroxide or potassium carbonate) to pH 9-10. The organic phase was separated, concentrated, and the crude material purified by low-temperature recrystallization from toluene in hexane to give compound I in 72% yield.
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