| Popis: |
ORD and CD measurements on α-alkylphenylacetic acids with primary, secondary, and tertiary α-substituents agree with the evidence from gas chromatographie retention times of their diastereoisomeric amides in leading to the conclusion that all (+)- acids of the series possess the same configuration. All members of the series show two positive CD bands in the 210 to 230 nm region, and these are ascribed respectively to the benzene ′ l a , transition, and to a mixed transition involving overlap of the π orbitals of the benzene ring with the 2p y and π* orbitals of the carbonyl portion of the carboxyl group. Conformational effects due to the size of the α-alkyl substituent are shown to influence the intensity of the mixed transition. |
