Cotton effect of dimedone and dihydro-resorcinol condensation compounds of amino acids and peptides

Abstract

Dimedone and dihydroresorcinol condensation compounds of aliphatic and alicyclic amino acids having the ( R) configuration exhibit a positive Cotton effect in the 280 mμ region. Conversely, the enantiomeric ( S) condensates show a negative Cotton effect. The homoconjugated chromophore present in the condensation compounds of aralkylamino acids in which the asymmetric center is separated from the aromatic ring by a methylene leads to an inversion in sign of the Cotton effect. The ( R) derivatives show negative optical rotatory dispersion curves, whereas the ( S) antipodes present positive curves. The Cotton effect of some peptides is also discussed.