Acetogenins, structural chemistry

Acetogenins, structural chemistry, 136-8 Acetone, manufacture, 617 Acetonitrile... 

The most characteristic aspect of the chemistry of secondary metabolites of the red algae is the extreme abundance of halogenated derivatives, whether they are of terpenic nature or are derived from acetogenins. It is, however, important to note that the presence of halogens on carbon skeletons applies only to three orders, Ceramiales, Giga-rtinales and Nemaliales, which total about 1000 different structures. A second characteristic of the secondary metabolites of Rhodophyceae is the precision of the chemo-taxonomic relationships between the orders and the nature of the metabolites they produce. As a general rule, it was fotmd that the chemical structures vary somewhat within an order, but much more from one order to another, with hardly any exceptions to these observations in just over 1500 structures. These chemotaxonomic relationships are collected in Table 13.6, where we consider the classification of six orders. 

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