Abstract: | Summary 1. The integral intensities of the bands of the skeletal vibrations of the heteroaromatic ring in the 1480–1630-cm–1 region of eight furanoquinoline alkaloids have been measured.2. A connection has been found between the values of A and the structures of the furanoquinoline alkaloids and their derivatives which enables such a series of heteroaromatic compounds to be identified: It has been shown that the introduction of an -OCH3 group into the position of the pyridine nucleus leads to a marked rise (almost twofold) in the value of A;In derivatives of dictamnine (VII-XII), the value of A depends on the position of the methoxy group and on the nature of the substituent in position 7 of the benzene ring;With an increase in the delocalization of the unshared pair of electrons of the oxygen atom of the furan ring, the value of A of the series of alkaloids investigated (VI-XIV) decreases; andCompounds (V-XIV) have the very high values of A of 5.0–7.0 practical units and they exceed the value of the intensities of the carbonyl bandsv(C=0).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 223–227, March–April, 1976. |