Sesquiterpenoid Alkaloids

In a projected synthesis of Nuphar quinolizidine alkaloids, it was shown by X tay analysis that the reaction of the pyridine 

Reagents i, EtOH, reflux ii, LiAlH, THE, reflux iii, Et2NSiMe iv, Me Sil, 

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A synthetic approach to the sesquiterpenoid alkaloid, dendrobine (103) has been announced. This involved the formation of the bicyclic ketone (105) by a Diels-Alder reaction of carvotanacetone (104) with butadiene. c/s-Hydroxyla-tion of (105), followed by periodate cleavage and aldolization, led to (106) which was converted into the ketal-ester (107) by standard procedures. Reaction of... 

Investigation of Allophylus cobbe, Homalium foetidium, and Aglaia species for alkaloid content has so far yielded only simple aromatic amide derivatives. An interesting phenethylamine-sesquiterpenoid alkaloid, elegantine, has been isolated from Saussurea salsa and S. elegansV NJV-Dimethylamino-p-hydroxy-phenethylamine is the first alkaloid to be extracted from marine algae. ... 

Dendrobium findlayanum Sesquiterpenoid Alkaloids Dendrobine (43 R = H) 2-Hydroxydendrobine (43 R = OH) Nobiline (44) 58... 

In the past few years several pyridine and piperidine alkaloids of obvious terpenoid origin have been encountered and will be reviewed here. Since many of the sesquiterpenoid alkaloids have been reviewed elsewhere in this treatise (Volume IX, Chapter 10) they have not been included. 

The alkaloids of this chapter are classified according to the classification of terpenoids, namely hemiterpenoid alkaloids (alkaloids with a C5 unit), monoterpenoid alkaloids (alkaloids with a Cjo unit), sesquiterpenoid alkaloids (alkaloids with a C15 unit), diterpenoid alkaloids (alkaloids with a C20... 

Medical Uses of Monoterpenoid Alkaloids Sesquiterpenoid Alkaloids Dendrobium Alkaloids Nuphar and Castor Alkaloids Alkaloids of the Celastraceae and Hippocrateaceae Khat... 

Miscellaneous Types of Sesquiterpenoid Alkaloids Diterpenoid Alkaloids... 

The presence of complex sesquiterpenoid alkaloids in both the Celastraceae and Hippocrateaceae confirms the close relationship between these families. 

Sesquiterpenoid alkaloids similar to those of other celas-traceous plants occur in leaves of khat (Brenneisen and El-Sohly, 1992 Crombie, 1980) but do not appear to be responsible for the effect of chewing fresh khat (Szendrei, 1980). The active compound is a simple amine, cathinone (see Chapter 28). A series of complex sesquiterpenoid cathedulin alkaloids has been characterized from khat (Crombie et al., 1990). 

Other sesquiterpenoid alkaloids are found in Fabiana im-bricata (Solanaceae) [fabianine (22)] and in Pogostemon pa-... 

Sesquiterpenes are aliphatic or cyclic, isoprenoid Cl5 -compounds encompassing an almost bewildering array of structural types (cf. Figs. 106-108). They may be saturated or contain isolated double bonds. Often hydroxy, oxo, aldehyde, carboxylic acid, and lactone groups are present. Most compounds are volatile and lipophilic. Nitrogen-containing sesquiterpenes (sesquiterpenoid alkaloids) occur in some families of higher plants. 

Stachyflin, a novel sesquiterpenoidal alkaloid, was isolated from a culture broth of Stachybotrys sp. RF-7260... 

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