Zur Konstitution der Alkaloide Olivacin, Guatambuin und u-Alkaloid D.Aspidosperma-Alkaloide, 5. Mitteilung

Novel 13H-indolo[3,2-c]acridines and Their Methyl Derivatives

7-Phenyl-13H-indolo[3,2-c]acridines (2a–e) have been prepared from 2,3,4,9-tetrahydro-1H-carbazol-1-ones (1a–e) via the intermediate 5,6-dihydro-derivatives (3a–e), and 13H-indolo[3,2-c]acridines (8a–e) from the 1-(N-phenylamino)carbazoles (7a–e). Methylations of 2 and 8 have been carried out, and UV spectral studies on the title compounds and the methylated products are presented, along with plausible mechanisms for the formation of the final compounds.

Syntheses of Pyrazolo-, Isoxazolo-, Pyrido- and Pyrimido-Carbazoles from 2-(3′,4′-Dimethoxybenzylidene)-2,3,4,9-Tetrahydrocarbazol-1-Ones

Mixed aldol condensation of 2,3,4,9-tetrahydrocarbazol-1-ones with 3,4-dimethoxybenzaldehyde (veratraldehyde) yielded 2-(3′,4′-dimethoxybenzylidene)-2,3,4,9-tetrahydrocarbazol-1-ones. These enones on reaction with hydrazine hydrate, hydroxylamine hydrochloride, malononitrile and guanidinium nitrate under different conditions yielded the corresponding pyrazolo[3,4-a]-, isoxazolo[3,4-a]-, pyrido[2,3-a]-, and pyrimido[4,5-a]-carbazoles respectively. The molecular and crystal structure of 2-(3′,4′-dimethoxybenzylidene)-2,3,4,9-tetrahydro-1H-carbazol-1-one resolved by single crystal X-ray diffraction is discussed.

Plants in traditional medicine in Brazil

Brazil has a long tradition of popular medicine in its different geographical areas (Amazonas, highlands and coast) and different cultural groups (Aruak, Tupi, Guarani). Recently the documentation of plants used in traditional medicine has been organized in Maceió, Brazil, but pharmacological investigations of these plants have been limited so far. High-level chemical research on natural products is developing quickly in the Federal Universities, but it is only seldom centred on medicinal plants. An exception is constituted by the Institute of Antibiotics of the University of Pernambuco where a multi-year programme on the chemistry of plants with pharmacological properties has been developed. Much interest is being shown in these studies, and the results should be coordinated and developed further.