Ipomoea Alkaloids

The previously published structure (5) of the alkaloid ipomine, from Ipomoea muricata Jacq., has been questioned. It has now been suggested that the signals from the sugar moiety in the n.m.r. spectrum should be re-assigned, and that ipomine is ipalbidinyl-(6-0-p-coumaroyl-/3-D-glucopyranoside) (6), and not the 4-0-p-coumaroyl-j8-D-glucopyranoside (5). The formulae (5) and (6) depicted 

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VII. Alkaloids Bearing Aromatic or Heteroaromatic Substituents A. IPALBIDINE AND RELATED IPOMOEA ALKALOIDS... 

Jenett-Siems K, Weigl R, Kaloga M, Schulz J, Eich E. Ipobscurines C and D macro-lactam-type indole alkaloids from the seeds of Ipomoea obscura. Phytochemistry 2003 62 1257-1263. 

Friedman, M., Dao, L., Gumbmann, M. R. (1989). Ergot alkaloid and chlorogenic acid content in different varieties of morning-glory (Ipomoea spp.) seeds. J. Agric. Food Chem., 37, 708-712. 

Ergine, molecular formula C16H17N3O, is the amide of D-lysergic acid, and commonly known as LSA or LA-111. It is an ergoline alkaloid that occurs in various species of the Convolvulaceae, and in some species of fungus. Rivea corymbosa (ololiuqui), Argyreia nervosa (Hawaiian baby woodrose) and Ipomoea violacea (tlitliltzin) are three major sources of this alkaloid. 

Although the indolizine nucleus appears not to occur naturally, its perhydro derivative, commonly named indolizidine, is the alkaloid 8-coniceine, and this nucleus is to be found in several groups of alkaloids including those from the plant groups Ipomoea, Elaeocarpus, Tylophora, Amaryllidaceae, and Orchidaceae. Since the chemistry of these alkaloids has been reviewed regularly,1 only selected examples will be taken from the natural products field. 

Another observation of similar importance is the first isolation of an alkaloid of the peptide type from higher plants. Ergosine (20) (and ergosinine) as well as agroclavine were found in Ipomoea argyrophylla Vatke (21). 

Chromatograms of the alkaloidal extracts of 25 meg. of Turbina (Rivea) corymbosa (I), and 25 meg. Ipomoea violacea (II). 

Marker , A., Steffan, N., Floss, K., Hellwig, S., Steiner, U. Drewke, C., Li, S.-M., Boland, W. and Leistner, E. (2008) Biosynthesis and accumulation of ergoline alkaloids in a mutualistic association between Ipomoea asarifolia (Gonvolvulaceae) and a Clavicip-italean fungus. Plant Physiol, 147,296-305. 

The biosynthetic pathway to the ergoline nucleus proceeds through 4-dimethylallyl tryptophan (4-DMAT), chanoclavine-I, agroclavine, and lysergic acid. Two cis, trans isomerizations occur one before chanocla-vine-I and the other before agroclavine, as shown by experiments with [2- C]-mevalonic acid and [Z-CH3]-4-DMAT (Fig. 36). The peptide unit is derived from a combination of three amino acids, one of which is always proline. Several genera in the plant family Convolvulaceae Rivea, Ipomoea, etc.) also produce ergot alkaloids. 

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