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

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Reaction Steps

(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).

Provenance & Evidence