Myrmicaria ants

Figure 9.10 More complex alkaloids from ants The indolizidines where R is butyl, hexyl and 3-hexenyl have been known from the venom o/Monomorium pharaonis, pharaoh s ant, for some time. The 2-heptyl-8-methyl-pyrrolizidine is from a Soienopsis ant. The keto-indolizidine is from an African Myrmicaria ant. There are eight of the tetraponerines from Tetraponera species from New Guinea...

Recently a whole series of indolizidine and pyrrolo-indolizidine alkaloids have been found in Myrmicaria ants (Figure 9.12), which evidently have a similar origin to the indolizidines in Figure 9.10. Note that they are all constructed from straight carbon chains. The structures of the complex dimer and trimer were deduced from NMR and mass spectral studies. 

Figure 9.12 Some complex alkaloids from the venom o/Myrmicaria ants from Africa.

Many insect defensive alkaloids have already been synthesized and several of these syntheses have already been reviewed (e.g., [13,114,116]). Here we will limit ourselves to the presentation of recent syntheses of Myrmicaria and Tetra-ponera ant alkaloids. 

The venom of ants of the genus Myrmicaria is made up of indolizidine or pyrrole-indolizidine alkaloids [188,189]. The synthesis of some of these alkaloids has already been reported in the review of Leclercq et al. [114]. Thus, we will report here only on the syntheses published since 1999. 

Kaib, M., Eisermann, B., Schoeters, E., Billen, J., Franke, S. and Francke, W. (2000). Task-related variation of postpharyngeal and cuticular hydrocarbon compositions in the ant Myrmicaria eumenoides. J. Comp. Physiol. A, 186,939-948. 

Lengyel, F., Westerlund, S. A. and Kaib, M. (2007). Juvenile hormone HI influences task-specific cuticular hydrocarbon profile changes in the ant Myrmicaria eumenoides. 

The heterocyclic hemi-aminal 44 was formed as a model for the synthesis of the marine alkaloids zoanthamine and zoanthenol and is derived from the cyclic imine formed by the reduction of an appropriated substituted azide <07H(72)213>. A pyrrolidine-fused azepine has been isolated from the venom of the ant Myrmicaria melanogaster and assigned as 45 based upon GC and FT-IR comparison with synthetic material <07JNP160>. The axially chiral doubly bridged biphenyl azepine 46 has been synthesised and used with oxone as an epoxidation catalyst in a biphasic system <070BC501>. 

Two new 3,5-disubstituted indolizidines, (-)-myrmicarin 237A and (+)-myrmicarin 237B, Fig. (7), were isolated as the major components of the poison gland secretion of the afiican ant Myrmicaria eumenoides [22]. NMR data analysis ( H, COSY, COLOC and... 

The poison glands of Myrmicaria species contain not the typical proteinaceous venom of most other myrmicine ants, but large quantities of mono-terpene hydrocarbons, such as -myrcene, / -pinene and limonene (Brand et al., 1974 Longhurst et al., 1983). The secretion is emitted from the tip of the sting in discrete droplets, and in addition to their defensive role, several of the compounds act as releasers of alarm behavior in workers. Since in this case single droplets of secretion can be collected and analysed, the exact amounts of each component can be measured, as can the behavioral threshold concentrations. 

Identification of the venom constituents of Myrmicaria melanogaster (Emery), an ant species native to the island of Borneo and collected in the sultanate of Brunei Darussalam, was based mainly on various mass spectrometric techniques, and on vapor-phase gas chromatography—Fourier transform infrared spectroscopy. Known alkaloids in the extract were also corroborated by spectroscopic or chromatographic comparison with... 

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