CD spectral study of Dnp derivatives of amino acids and peptides for their configurational and conformational analysis.

Rules relating the stereochemistry of N-Dnp (Dnp: 2,4-dinitrophenyl) derivatives of alpha-amino acids and peptides and the sign of the Cotton effects at the longest wavelength band (ca. 400 nm) are surveyed. Some new data and insights concerning the CD spectra of Dnp-alpha-amino acids are included: i.e., the spectra of Dnp derivatives as the composite of the corresponding o-nitrophenyl and p-nitrophenyl derivatives; the crystal structure of Dnp-I-phenylalanine and its solid-state CD spectra; the CD spectra of Dnp-alpha-amino acids containing sulfur atom on their side chains; and the theoretical approach to the CD spectra using molecular orbital method-based calculation. Conformational analyses of cyclic and linear peptides by the CD spectra of their Dnp derivatives are also discussed.