Monomorium alkaloids

A rapid GC-FT1R method for determination of the cis or trans configuration of 2,6-disubstituted piperidines was developed using, among others, the Solenopsis alkaloids 198a, 198b, 202 and the Monomorium alkaloids 207-209 [480]. A method for determination of the absolute configuration of Solenopsis alkaloids was developed, in which the amines are... 

Besides piperidine alkaloids, a total of 19 pyrrolidines have been found in the secretions of thief ants and fire ants of the genera Solenopsis and Monomorium. Among these, compounds 80-84 are simple pyrrolidines with two saturated linear all-carbon side chains only in Solenopsis latinode is there a secondary amine (82) and its methylated analog (85). One or two terminal unsaturations are present in compounds 86-91, which all possess a (hex-l-en)-6-yl chain and a 5-, 7-, or 9-carbon saturated chain. Compounds 93, 94, 96, 97, and 98 are the A-l-pyrrolines corresponding to pyrrolidines 80, 82, 90 (93 and 96 corresponding to 80, 94 to 82, and 97 and 98 to 90). 

Several species pertaining to the sub-family Myrmicinae (e.g., Solenopsis spp., Monomorium spp.) are characterized by a venom rich in dialkylated saturated nitrogen heterocycles (e.g., piperidine, pyrrolidine, indolizidine, pyrrolizidine). Exhaustive lists of these alkaloids have already been published [114-116]. Since then, only a few more of these alkaloids have been reported from a few further species. 

Farnesylamine (123) (Fig. 20), a sesquiterpene alkaloid, was recently detected in whole extracts of Monomorium fieldi [129]. This compound had already be prepared by synthesis and found to display a whole range of biological activities. Among others, it inhibits arthropod molting, squalene synthesis, and the growth of malignant tumor cells, modulates human T cells and has anti-osteo-porosis activity [129]. 

More than a dozen 2,5-dialkylpyrrolidines have been identified in the venoms of Solenopsis and Monomor ium species (J7) AH of these compounds are of the trans configuration. Whereas Solenopsis species may produce only one compound in their poison glands, the venoms of Monomorium species generally consist of mixtures of these alkaloids. 

A variety of Monomorium species in the subgenus Monomor ium produce these alkaloids (I) (6, 12, 12), ... 

Several N-methylpyrrolidines have been identified in the venoms of Monomorium (Monomorium) species. M. latinode, an Old World species, is distinctive in producing an alkaloidal-rich venom containing two N-methylpyrrolidines with saturated side chains (IV) (6J. On the other hand, the poison gland secretions of several North American species contain N-methylated compounds in which one (V) or both side chains (VI) are terminally unsaturated (6 ) they are accompanied by the corresponding norpyrrolidines. 

The disubstituted pyrrolidines and piperidines have been demonstrated to be excellent repellents for ants under field conditions. Workers of Monomorium pharaonis effectively repel other species of ants with venom droplets which accumulate on the tip of the sting (37), a strategy that is used with equal success by workers of North American Monomorium species ( 38.) and the European thief ant, Solenopsis fugax (37). The venom of the latter species contains a single alkaloid, trans-2-butyl-5-heptylpyrrolidine (I, m=3, n=6) (1 ), and the... 

Disubstituted indolizidines, unlike many classes of amphibian alkaloids, are not unique to amphibians. 3,5-Disubstituted indolizidines such as monomorine I [(5Z,9Z)-195B] occur in ants of the genera Monomorium and Solenopsis (125,129,134). Some of the ant indolizidines are as follows (5Z,9Z)-3-n-butyl-5-methylindolizidine (monomorine I), (5Z,9Z)-3- -ethyl-5-methylindolizidine, (5Z,9Z)-3-hexyl-5-methylindolizidine, and (5 ,9Z)-3-butyl-5-(4-pentenyl)indolizidine. A series of 5-substituted indolizidines, the piclavines, were reported recently from a marine tunicate (Clavelina picta) (135). 

All the currently known indolizidine and quinolizidine alkaloids isolated from ants are illustrated in Fig. 6. (+ )-Monomorine I (427), the well-studied trail pheromone constituent of the Pharaoh ant Monomorium pharaonis), and the analogs 428-431 were described in the earlier volumes in this series. These five compounds are 3,5-disubstituted indolizidines bearing short saturated or mono-unsaturated hydrocarbon chains. The relative stereochemistry in monomorine VI (430) still remains unknown, while that of 431 was atypical for the class at the time of its isolation 380). The structural resemblance of fiiis group of alkaloids to the... 

Following the initial discovery of alkyl-substituted piperidines in Solenopsis venom, a very large number of structurally related alkaloids were identified in the venom from ants of the subfamilies Myrmicinae and Pseudomyrmicinae, all of which share a carbon skeleton based on a single unbranched chain. Analyses of ants from the genera Solenopsis, Monomorium, and Diplorhoptrum revealed 2,5-dialkylated pyrrolidines,... 

The ant venom alkaloids occurring in the genera Solenopsis and Monomorium have been reviewed briefly. The venoms of iMy latinode and M subopacum contain an array of 2,5-dialkylpyrro-lidines (1), and the pyrrolines (2) are also present. All were identified by gas-chromatographic separation followed by mass spectrometry. ... 

Ants in the myrmicine genera Solenopsis and Monomorium are distinctive in producing venoms that are dominated by alkaloids rather than proteins (15). Fire ants (Solenopsis spp.) in the subgenus Solenopsis characteristically synthesize poison gland secretions that are dominated by the cis- and trans-isomers of 6-alkyl- or 6-alkylidene-2- methylpiperidines ( ). On the other hand, species in the subgenus Diplorhoptrum frequently produce... 

In view of the reported deterrent activities of Solenopsis and Monomorium venoms under field conditions (1, IJ., 12), it seemed worthwhile to evaluate the comparative repellencies to ants of some of these venom-derived alkaloids. In this investigation, the deterrency of these nitrogen heterocycles to a variety of ant species was determined by using a feeding bioassay in which the reactions of hungry ant workers to alkaloid-treated food were quantified Selection of a variety of aggressive ant species... 

Queenright (queen-containing) colonies of 10 species of ants, belonging to two major subfamilies, were utilized for repellency studies. Members of the subfamily Myrmicinae included Solenopsis invicta, Crematogaster ashmeadi. Pheidole dentata, Monomorium minimum. M. viridum and pharaonis. The subfamily Dolichoderinae was represented by Iridomyrmex pruinosus, I. humilis. Tapinoma sessile, and T melanocephalum. Whereas S. invicta and the Monomorium species have been demonstrated to synthesize alkaloid-rich venoms (36, ), these nitrogen... 

Both foraging and feeding were stimulated by not providing the ant colonies with food for 48 hours. Food was then offered to the ants as droplets of honey to which were added 1 or 2 pg of alkaloids in 2 pi of absolute ethanol. In one study, both treated droplets and colonies were randomized for each replicate which compared the repellencies of four alkaloids that included a Solenopsis alkaloid, trans-6-tmdecyl-2-methylpiperidine (36), two Monomorium dialkylpyrrolidines Solenopsis... 

Indolizidine alkaloids are produced by the Pharaoh ant, Monomorium pharaonis. This tropical ant is now a common... 

---