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Optical activity of simple cyclic amides in solution
Author(s) -
Greenfield Norma J.,
Fasman Gerald D.
Publication year - 1969
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1969.360070415
Subject(s) - chemistry , circular dichroism , optical rotatory dispersion , dipeptide , cotton effect , acetonitrile , solvent , vibrational circular dichroism , crystallography , red shift , photochemistry , stereochemistry , organic chemistry , amino acid , biochemistry , physics , quantum mechanics , galaxy
The cyclic dipeptide, L ‐alanylglycyl anhydride, has been studied by optical rotatory dispersion; both L ‐alanylglycyl anhydride and the lactam, L ‐3‐aminopyrrolidin‐2‐one, have been studied by circular dichroism. In hydroxylic solvents the circular dichroism spectra of 3‐aminopyrrolidin‐2‐one can be attributed to an n –π* transition near 220 mμ and a π–π* transition near 190 mμ. In these solvents the optical activity of L ‐alanylglycyl anhydride can be explained as being due to contributions of n –π* transitions and a split π–π* transition. In acetonitrile, however, the circular dichroism spectrum of 3‐aminopyrrolidin‐2‐one shows an additional apparent minimum near 200 mμ. The CD spectrum of the dipeptide is also quite distinctive in this solvent. The possible nature of the band at 200 mμ and the implications of these findings are discussed.