Iridomyrmex ants

The iridoid term comes from the genus where the first iridoid was isolated, Iridomyrmex ants, that synthesize iridodial, Fig. (1) with a defensive finality [1]. In plants, the study of iridoids started in the middle of the XIX century, with the isolation of asperuloside [2] or gentiopicroside [3], but is not till 1960 decade when the iridoids have reached the highest interest for Scientifics. 

The ant Iridomyrmex pruinosus utilizes 2-heptanone as an alarm pheromone. Figure 17 illustrates the existence of a close correlation of the similarity between 2-heptanone and its analogs in molecular model silhouettes with their alarm activity45. It is noteworthy that the replacement of the methylene group in position 3 of 2-heptanone by the ether linkage yields n-butyl acetate which has the same activity as the natural pheromone. Considerable activity is still retained even when the carbonyl group is replaced by the hydroxyl group. 

Akita and Ohta disclosed one of the earliest Sonogashira reactions of chloropyrazines and their A-oxides [24, 25]. The union of 2-chloro-3,6-dimethylpyrazine (23) and phenylacetylene led to 2,5-dimethyl-3-phenylethynylpyrazine (29). Subsequent Lindlar reduction of adduct 29 then delivered (Z)-2,5-dimethyl-3-styrylpyrazine (30), a natural product isolated from mandibular gland secretion of the Argentine ants, Iridomyrmex humilis. 

Aetinidine (9a) has been identified as an anal gland product of three species of dolichoderine ants in the genera Conomyrma and Iridomyrmex (Table I). The venoms of ants of the Myrmecia species are rich in histamine (136) (Table VIII), which can act as a defensive substance, together with hemolytic, smooth-muscle-stimulating, and histamine-releasing components. 

Chart 8.1.1 Isoprenoids (skeletons) widespread on land (5max=45, av=29 S/Hm x-0.60, av=0.47). Monoterp. men thane (Compositae, Ang. from temeperateand subtropical, not forested, areas and Bryoph. AY) thujane (Ang. AY) bomane camphor and bomeol (tropical and subtropical Lauraceae and Mediterranean Labiatae, Ang. AY) pinane (Ang. and Gymn. MI AY) iridoids (Ang. and Argentine ant, Iridomyrmex humilis Mayr., Ins. BR MI). 

Markin, G. P. (1970). Food distribution within laboratory colonies of argentine ant, Iridomyrmex humilis (Mayr). Insectes Sociaux 17 127-158. 

The structure for valerosidate is incorrect in the previous Report (Vol. 5, p. 17). A new valepotriate has been isolated from Valeriana officinalis and shown spectroscopically to be 7-epideacetylisovaltrate (103) 193 it is also shown to be related to didrovaltrate (104) stereochemically, but in view of the recently reported absolute configuration of didrovaltrate (104)192 this assignment must be questioned. The occurrence of iridoids in the Argentine ant Iridomyrmex humilis has been re-investigated.194... 

Actinidine (92), a plant alkaloid (see section 8), is also a minor component of the defence secretion of the Australian cock-tail ant Iridomyrmex nitidceps (G.W.K. Cavill et al.. Tetrahedron, 1982, 38, 1931), a fact which indicates that ants may obtain toxins (or at least their precursors) from dietary sources. Actinidine has been synthesised (M. Nitta, A. Sekiguchi and H. Koba, Chem.Letters, 1981, 933). Anabaseine (118), a dihydro derivative of anabasine a well known tobacco alkaloid, is present in the poison glands of Aphaenogaster ants for which it also an attractant (J.W. Wheeler et al.. Science, 1981, 211, 1051). Ants from Puerto Rico produce the simple tetrahydropyridine (119) (T.H. Jones, M.S. Blum and... 

Actinidine (91) is produced by several insects. It was found to be a component of the ants Iridomyrmex discors [267], and I. purpureus [268], Pygidial gland secretions of the ant Tapinoma melanocephalum contained 91, and the alkaloid was repellent to worker ants of this species [269], Actinidine was identified in a defensive secretion of the stick insect Megacrania alpheus [270], and it was present in trace amounts in the defensive secretion of rove beetles [271] and leaf beetles [272]. Ventral glands of Nematus sawfly larvae also contained low levels of 91 [273],... 

New 2,6-dialkylated piperidines (207-210) have been isolated as cis/trans mixtures from the ant venom of Monomorium delagoense [487], Their structures were determined using MS, catalytic hydrogenation to the hydrocarbons, and methoxymercuration-demercuration followed by MS analysis. The structures of 207-209 were confirmed by synthesis of the cis/trans mixtures from the corresponding dialkyl pyridines. The major venom component, cis/trans 207, displayed potent insecticial activity against Reticulitermes worker termites (LD50 = 150 pg/g termite). In addition, 207 was a potent repellent for the ants Pheidole and Iridomyrmex [487],... 

Occurrence I. was first isolated from the Australian ant Iridomyrmex detectus and the hunting beetle Sta-phylinus olens, Coleoptera Staphylinidae). It was later also found in the essential oil of a not exactly defined Australian species of Myoporum. Nepetalac-tone occurs in the essential oil (51%) of the genuine catmint Nepeta cataria, Lamiaceae) and is an attrac-tant for cats. 

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... 

All of these components possess the molecular formula C10HJ6O2 (mw 168 amu). Among these, the former two compounds are the reduced form nepetalactones [5], which is the main component of catnip, Nepeta cataria (Labiatae), known as a favorite plant of cats in the United States. The latter two components are also present in the postbinary anal gland secretions of the Argentina ant Iridomyrmex humilis) and Iridomyrmex nitidus and work as defensive substances [6—8].Therefore, these Cjo compounds with such skeleton are sometimes called iridoids. 

The compounds iridomyrmecin (1) and iridodial (2) serve as defensive compounds in ants of the genus Iridomyrmex. Nepetalactone (29), from Nepeta cataria, Lamiaceae, is insecticidal. Eisner (1964) demonstrated that this compound is repellent to 17 out of 24 insect species studied. Nepetalactone also has been reported to have hallucinogenic properties in humans. Nepetalactone and a similar compound, boschni-alactone (40) from Boschniakia rossica (Orobanchaceae), have attractive activity toward cats (Herout, 1970) (Fig. 20.9). These compounds occur free, in contrast to most iridoid compounds. 

Iridomyrmecin (1) and isoiridomyrmecin (44) are used by ants such as Iridomyrmex humilis, /. nitidis, and Doli-choderus scabridus as defensive compounds. These lactones also were found in Aphis polygama. Thus, the structures of the lacewing atb-actants correspond to the reduced forms of the defensive compounds of ants (Sakan et al., 1970). 

Actinidine (8) is found in the defensive secretion of the Australian cocktail ant, Iridomyrmex nitidiceps (Fodor and Colasanti, 1985). This compound is alleged to be attractive to cats. 

Constit. of various ants incl. Cataglyphis sp. and Iridomyrmex sp. 

Iridoids are monoterpenes with a carbocyclic five-membered ring. Their designation is derived from iridodial, a constituent of the defence secretions of ants of the genus Iridomyrmex,... 

Van Vorhis Key, S.E. T.C. Baker. 1982. Specificity of laboratory trail following by the Argentine ant, Iridomyrmex humilis (Mayr), to Z-9-hexadecenal, analogs, and gaster extracts. J. Chem. Ecol. 8 1057-1063. 

In 1949 Pavan isolated the substance he called iridomyrmecin from the Argentine ant Iridomyrmex humilis (now Linepithema humile). Iridomyrmecin, dolichodial and other monoterpenes with a methylcyclopen-tanoid structure are called iridoids (Figure 6.12). They act as defensive compounds in ants, stick insects, rove beetles and leaf beetle larvae. Some of the group (e.g. the isomer of nepetalactone shown in Figure 6.12) are also sex pheromones in aphids. Reaction of iridomyrmecin with... 

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