Fragmentation of the macrocyclic ring of alkaloids with the otonecine nucleus

Summary It has been shown that the fragmentation of the macrocycle of the otonecine bases qualitatively resembles the decomposition of macrocyclic alkaloids with the retronecine skeleton. The presence of an oxygen-containing substituent at C₅ and of an alkoxy group at C₂, when there is no C₅=C₆ double bond, substantially changes the direction of decomposition of the macrocycle.A similarity of the spectra of 11- and 12-membered bases with similar mutual orientation of CH₃ groups at C₂ and C₃ has been noted.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 66–71, January–February, 1976.