L-Leucine → N-(3,5-dinitrobenzoyl)leucine

Reaction equation

[NH2:1][C@H:2]([C:7]([OH:9])=[O:8])[CH2:3][CH:4]([CH3:6])[CH3:5].[N+:10]([C:13]1[CH:14]=[C:15]([CH:19]=[C:20]([N+:22]([O-:24])=[O:23])[CH:21]=1)[C:16](Cl)=[O:17])([O-:12])=[O:11].C1OC1C>O1CCCC1>[N+:10]([C:13]1[CH:14]=[C:15]([CH:19]=[C:20]([N+:22]([O-:24])=[O:23])[CH:21]=1)[C:16]([NH:1][C@H:2]([C:7]([OH:9])=[O:8])[CH2:3][CH:4]([CH3:6])[CH3:5])=[O:17])([O-:12])=[O:11]

Participants

Procedure

(S)-Leucine (10 g) was suspended in 150 mL dry tetrahydrofuran and chilled in an ice bath while stirring under a nitrogen atmosphere. 3,5-Dinitrobenzoyl chloride (Table 2, Compound 13, 21 g) and propylene oxide (6.6 g) were added; the resulting heterogeneous mixture became clear after several minutes. The mixture was allowed to stir for 5 h, and was evaporated under reduced pressure to afford an oil which crystallized upon addition of 100 mL of cold dichloromethane. Filtration and drying of the resulting crystals afforded 3,5-dinitrobenzoyl-(S)-leucine, 14, as a white solid (20.64 g, 83% yield). 1H NMR (200 MHz, d6DMSO) δ: 0.95 (m,6H), 1.75 (M,3H), 4.25 (m,1H), 9.00 (t,1H), 9.17 (d,2H), 9.41 (d,1H).