Defensive compounds carbon-based

The preparation of cyanohydrins is an important reaction in organic synthesis because it is used to lengthen the hydrocarbon chain by one C-atom the molecule of 1-cyanopropanol in the scheme above has one carbon atom more than the starting propanal. Some cyanohydrins are natural products, especially the derivatives of benzaldehyde, which are poisonous and used by particular insects for their defense. The toxic activity of these compounds is based on the hydrolysis of cyanohydrins into benzaldehyde and highly toxic HCN. 

Diterpenes are currently represented among ciliates by two compounds, focardin and epoxyfocardin, both isolated from cultures of the species Euplotes focardii, collected from the Italian Antarctic base located on the Ross Sea. Like the previous derivatives, these diterpenes are toxic to other species of ciliates and could therefore be used for chemical defense by E. focardii (Guella, Dini, and Pietra, 1996b). Currently, no more lactones seem to have been found in ciliates, but it is interesting to note that the carbon skeleton of focardin and its epoxy is an isoprenolog of that of rarisetenolide - both are mixtures of epimers. 

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