Lactam ergot alkaloids

Uhiig S, Petersen D (2008) Lactam Ergot Alkaloids (Ergopeptams) as Predominant Alkaloids in Scierotia of Claviceps purpurea from Norwegian Wild Grasses. Toxicon 52 175... 

Stuchlik, J., KrajiSek, A., Cvak, L., Spacil, J., Sedmera, R, Flieger, M., Vokoun, J. and feehaSek, Z. (1982) Non-cyclol (lactame) ergot alkaloids. Coll. Czech. Chem. Commun., 47, 3312-3317. 

Cyclols Stable molecules obtained by the addition of a heteroatom nucleophile to the carbonyl group of lactams are not very common. The side-chain moiety of the ergot alkaloids (e.g., 50) is one of the earliest examples of such a cyclolic structure (75FOR51) identified. This has given rise to a number of studies on the synthesis and chemical transformations of such units. The discussion below is confined to cyclols related to or arising from piperazine-2,5-diones. 

The Schmidt reaction with the dienone 11/102 (Scheme 11/15) yields the 1,4-thiazepine, 11/103. Treatment of its dihydroderivate, II/104, gives exclusively the enlargement product 11/105, in which the methylene group migrated [82]. A similar reaction can be observed if the synthetic ergot alkaloid precursors of type 11/106 are treated with in situ generated hydrazoic acid. Again no trace of the isomeric lactam can be observed [83]. 

Overall, however, the immensity of temperate land corresponds to a most various secondary metabolic production, different from that of tropical land. The most renowned alkaloids belong to the morphine class (Chart 6.2.A1), and, in combination with isoprenoids, to the ergot and triterpene classes (Chart 6.2. A2). Prominent in the peptides are the cyclosporins (the first of which was isolated from a fiingus collected in Norway), streptogramins, and P-lactams (Chart 6.2.P). The isoprenoids are represented by pyrethrin monoterpenes, cedrane sesquiterpenes, ginkgolide and taxane diterpenes, ophiobolane sesterterpenes, and arborane and amyrin-like triterpenes (Chart 6.2.1). In the polyketides, epothilones, recently discovered from Myxobacteria, and the long known rapamycin, are two prominent classes of macrolides (Chart 6.2.FA/PO/C). 

Flieger, M., Wurst, M., Stuchlik, J. and Rehacek, Z. (1981) Isolation and separation of new natural lactam alkaloids of ergot by high performance liquid chromatography. /. Chromatogr., 207,139-144. 

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