Alkamine structure elucidation

The most significant chemical progress in the last decade has been the isolation and structural elucidation of an increasing number of new steroidal alkamines and glycosides the structures of which, however, still belong to one of the known types 1-5. Extensive work has also been directed to a number of new partial and total syntheses as well as to the degradation of the alkamines, particularly to pregnane derivatives. A number of review articles have been published in the last years (e.g., 31-38). 

The alkamines isolated directly from plant material or obtained by acid or enzymatic hydrolysis of naturally occurring glycosides between 1967 and 1979 are summarized in Table III. Physical me ods are of increasing importance in structure elucidation. Recent papers have dealt with IR spectra (173), H NMR (174,175), NMR (176-178,357,358), EPR (179), ORD (180-183), and MS (184,351,352) of Solanum alkamines. Some X-ray analyses have been carried out since 1967 (58, 81, 149, 185-189, 359). Tables rV-VI survey the characteristic features of H NMR, NMR, and MS of Solanum alkaloids. Silver nitrate-containing adsorption layers were shown to be useful in TLC separation of 5a-saturated and S-unsaturated alkamines (194,195). High-pressure liquid chromatography has been applied successfully for the separation of steroidal Solanum and Veratrum alkamines (373). 

Table 7.3 Steroidal alkaloids (alkamines) alphabetically listed within the different structural types For 41 out of altogether 115 compounds from Solarium spp. (113 compounds), Lycianthes biflora, and Saracha punctata (one compound each) at least one corresponding glycoalktiloid was found and structurally elucidated, i.e., for 36% of the alkamines also corresponding glycosides are known (continued)...

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