ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Lobelia alkaloids. II. Reduction of lobelanines

D. Belluš, O. Liška, and F. Horák

Slovak Technical University, Bratislava

Abstract: cf. CA 60, 9099d. Catalytic hydrogenation, electroredn., and (iso-PrO)₃Al redn. of lobelanine (I) were described. In the catalytic hydrogenation of I in MeOH, in glacial AcOH, or in 40% AcOH, up to 2.5 moles H were used for each mole of I; PtO₂, Raney Ni, colloidal or spongy Pt, and Pd on pumice were the catalysts used. Regardless of the catalyst, the max. yield of lobeline (II) in the total mixt. of alkaloids was 46.6% at H consumption of 1.34 moles, but PtO₂ gave the most rapid reaction. Electroredn. of I on Hg and Pb electrodes was not a suitable method for the prepn. of II because of low yields (∼17%). Redn. of I with (iso-PrO)₃Al in iso-PrOH did not occur at 30-82°. In refluxing benzene, 80% of I was reduced to I and an unidentified isomer. The amt. of alkaloids formed in the redn. were detd. by paper chromatography.

Full paper in Portable Document Format: 182a90.pdf (in Slovak)

Chemical Papers 18 (2) 90–98 (1964)