Male-specific tetraene and triene hydrocarbons ofCarpophilus hemipterus: Structure and pheromonal activity

Males ofCarpophilus hemipterus (L.), the dried-fruit beetle, (Coleoptera: Nitidulidae) were found to emit nine all-E tetraene and one all-E triene hydrocarbons in addition to two pheromonally active tetraenes that had been reported previously. The previously known compounds are (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-decatetraene(1) and (2E,4E,6E,8E)-3, 5,7-trimethyl-2,4,6,8-undecatetraene(2). The new tetraenes were all related to structure1 by having one additional carbon at either one or two of the following four locations: at carbon 1 of the chain, at carbon 10 of the chain, at the 5-alkyl branch, or at the 7-alkyl branch. (Structure 2 also fits within this pattern.) The triene inC. hemipterus is (2E,4E,6E)-5-ethyl-3-methyl-2, 4,6-nonatriene. Also identified from volatile collections from the beetles were the 2Z and 4Z isomers of1. All structures were proven by synthesis, with NMR and mass spectral data for the compounds provided. Two of the newly discovered compounds, (2E,4E,6E,8E)-7-ethyl-3,5-dimethyl-2,4,6,8-decatetraene and (2E,4E,6E,8E)-7-ethyl-3,5-dimethyl-2,4,6,8-undecatetraene, were quite active in the wind-tunnel bioassay, but others, such as (2E,4E,6E,8E)-5-ethyl-3,7-dimethyl-2,4,6,8-decatetraene and (2E,4E,6E,8E)-4,6,8-trimethyl-2,4,6,8-undecatetraene were not. Structureactivity relationships are explored among the natural compounds and additional, synthetic analogs, which were never detected from the beetles. Some of these analogs, such as (2E,4E,6E,8E)-3,5-dimethyl-7-propyl-2,4,6,8-undecatetraene, were quite active in the bioassay. The biosynthesis of the beetle-derived compounds is discussed. A single biosynthetic scheme that lacks complete enzyme specificity at four specific steps could account for the entire series of compounds found in the beetles and their relative proportions. The definition of pheromone is discussed in relation to these hydrocarbons.     

3-Hexyl-5-Methylindolizidine Isomers from Thief Ants, Solenopsis (Diplorhoptrum) Species

The venom alkaloids from the workers of nine collections of Solenopsis (Diplorhoptrum) from California contain either (5E,9E)-3-hexyl-5-methylindolizidine (1c) or (5Z,9E)-3-hexyl-5-methylindolizidine (1d) along with cis-2-methyl-6-nonylpiperidine. The structures of these compounds were determined from their mass spectra and by comparison of their GC-FTIR spectra with those of a synthetic mixture. In view of the facts that a third diastereomer of 3-hexyl-5-methylindolizidine had been reported in previous collections of Solenopsis (Diplorhoptrum) queens from Puerto Rico, and that indolizidines along with other ant venom alkaloids are sequestered by amphibians, the determination of species in this difficult group of ants is significant. In particular, the chemotaxonomic value of the stereochemistry of these venom alkaloids is discussed.     

Novel pyrazines from the head of Australian ponerine antRhytidoponera metallica

The novel pyrazines, (E)- and (Z)-5-methyl-3-(2-methylbutyl)-2-(3-methylbut-1-enyl)pyrazine, (E)- and (Z)-5-methyl-3-isopentyl-2-(3-methylbut-1-enyl) pyrazine, (E)- and (Z)-5-methyl-3-(2-methylbutyl)-2-(3-methylpent-1-enyl)pyrazine, (E)- and (Z)-5-methyl-3-isopentyl-2-(3-methylpentl-enyl) pyrazine, together with the known pyrazines, 2,5-dimethyl-3-(2-methylbutyl)pyrazine and 2,5-dimethyl-3-isopentylpyrazine, have been identified from the head of the Australian ponerine antRhytidoponera metallica. Alkanes and alkenes, in small amounts, were also detected.     

Lasioderma chemistry sex pheromone of cigarette beetle (Lasioderma serricorne F.)

A chemical study of the sex pheromone of the cigarette beetle was carried out. Seven components were isolated from active fractions of column chromatography of the female extract, and their structures were elucidated by spectroscopic evidence and confirmed by synthesis to be (4S,6S,7S)-4,6-di-methyl-7-hydroxynonan-3-one (serricornin) (I), 2,6-diethyl-3,5-dimethyl-3,4-dihydro-2H-pyran (anhydroserricornin) (II), 4,6-dimethylnonan-3,7-dione (III), 4,6-dimethylnonan-3,7-diol (IV), 4,6-dimethyl-7-hydroxy-4-nonen-3-one (V), (2S,3R)-2,3-dihydro-3,5-dimethyl-2-ethyl-6-(l-methyl-2-oxobutyl)-4H-pyran-4-one (serricorone) (VI) and (2S,3R)-2,3-dihydro-3,5-dimethyl-2-ethyl-6-(1-methyl-2-hydroxybutyl)-4H-pyran-4-one (serricorole) (VII).These structural features suggested that the occurrence of these components might be related to the polyketide biosynthesis. The behavioral bioassay and BAG experiments revealed the biological role of each component in the copulatory behavior of this insect.     

Effect of some tripodal bipyrazolic compounds on C38 steel corrosion in hydrochloric acid solution

The corrosion inhibition of C38 steel in molar HCl by N,N-bis[2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl]buthylamine (P1) and 5-{N,N-bis[2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl] amino} pentanol (P2) has been investigated at 308 K using electrochemical and weight loss measurements. Measurements show that these compounds act as good inhibitors without changing the mechanism of the corrosion process. Moreover, the inhibiting efficiency increases with the increase in concentration of the studied inhibitors. Compound P2 showed better protection properties even at relatively higher temperatures when compared to P1. The associated activation corrosion and free adsorption energies have been determined. P1 and P2 are adsorbed on the C38 steel surface according to a Langmuir isotherm adsorption model.     

Chemistry of mandibular and Dufour's gland secretions of ants in genusMyrmecocystus

Males of several species ofMyrmecocystus produce mandibular gland secretions that contain 2,4-dimethyl-2-hexenoic acid and a variety of monoterpenes that include neral, geranial, citronellol, limonene, and 2,6-dimethyl-5-hepten-1-ol. Other components identified include methyl anthranilate, octanal, octanol, octyl octanoate, and 2-hexyl-2-decenal. Methyl salicylate has been identified as a mandibular gland constituent of workers of several species in addition to mellein and monoterpenes such as cymene, limonene, and the isomers of citral. The Dufour's gland secretions of workers and females of 14 species contain typical formicine alkanes (e.g., undecane), 2-alkanols (e.g., 2-tridecanol), and 2-alkanones (e.g., 2-tridecanone). Two species in the subgenusEremnocystus produce secretions that are distinguished by the presence of significant quantities of tridecyl esters. The functions of these compounds as well as their possible chemosystematic significance in the genusMyrmecocystus are discussed.     

Male-produced Aggregation Pheromone of Colopterus truncatus: Structure, Electrophysiological, and Behavioral Activity

A male-produced aggregation pheromone was demonstrated in Colopterus truncatus Randall (Coleoptera: Nitidulidae) by gas chromatographic comparisons of male and female volatile emissions. Male-specific compounds were identified with coupled gas chromatographic–mass spectrometric (GC-MS) analysis and GC and MS comparison of authentic standards. Physiological activity was evaluated by coupled gas chromatographic–electroantennographic (GC-EAG) recordings, and electroantennographic (EAG) assays of standards. The male-produced volatiles eliciting responses from male and female antennae (and relative abundance) were (2E,4E,6E)-3,5-dimethyl2,4,6-octatriene (1) (1.8), (2E,4E,6E)-4,6-dimethyl-2,4,6-nonatriene (2) (100), and (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-decatetraene (3) (3.3). A fourth male-specific compound, (2E,4E,6E,8E)-4,6,8-trimethyl-2,4,6,8-undecatetraene (4) (0.6) was not EAG-active. EAG dose–response studies showed that the antennae were most sensitive to 2 followed by 3 and 1. Synthetic 2, binary blends of 1 and 3, and tertiary blends of 1, 2, and 3 were highly attractive in the field when synergized with fermenting whole-wheat bread dough. In the field, cross-attraction to the C. truncatus pheromone components was observed for Carpophilus lugubris Murray, C. antiquus Melsheimer, and C. brachypterus Say.     

Influence of type and positioning of N-aryl substituents on vinyl polymerization of norbornene by Ni(II) α-diimine complexes

Effects of structural variations of the diimine ligand on catalyst activities for vinyl polymerization of norbornene (NB) have been investigated by a series of Ni(II) α-diimine catalysts of the general formula: [{ArN=C(Ac)-C(Ac)=NAr}]NiBr₂ (Ac=acenaphthyl) (Cat(H), Ar=C₆H₅; Cat(2,6-Me), Ar=2,6-C₆H₃Me₂; Cat(2,6-Et), Ar=2,6-C₆H₃Et₂; Cat(2,6- i Pr), Ar=2,6-C₆H₃ i-Pr₂; Cat(2,3-Me), Ar=2,3-C₆H₃Me₂; Cat(2,4-Me), Ar=2,4-C₆H₃Me₂; Cat(2,5-Me), Ar=2,5-C₆H₃Me₂; Cat(3,5-Me), Ar=3,5-C₆H₃Me₂; Cat(2,4,6-Me), Ar=2,4,6-C₆H₂Me₃). In situ reactions with methylaluminoxane generated the active catalysts, and they showed good activity towards NB polymerizations. As indicated by relatively higher activities of Cat(H) and Cat(3,5-Me), it can be generalized that catalysts having 2,6-substituents are less active due to steric interaction between monomer and substituents. In addition, electron donating methyl groups at 2-, 4-or 6-position on the N-aryl have a con effect and that at 3,5-position has a pro effect. This paper was presented at the 11th Korea-Japan Symposium on Catatysis held at Seoul, Korea, May 21–24, 2007.     

Azacrown Ethers with Naphthyl Branches. Fluorescence Properties,Protonation and Metal Coordination

Starting from 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane, we have prepared two compounds by replacing the amine hydrogens with naphthyl or 3,5-bis(2′-oxymethylnaphthyl)benzyl units. The absorption and emission spectra of compounds 2 (N,N′-bis(2-naphthylmethyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) and 3 (N,N′-bis[3,5-bis(2′-oxymethylnaphthyl)benzyl]-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) have been studied in CH₃CN:CH₂Cl₂ 1:1 (v/v) solution. For comparison purposes, the spectroscopic properties of N-methyl(2-methylnaphthalene)ethylamine (1) have also been investigated. For each compound, the absorption spectra are qualitatively very similar to that of naphthalene, with molar absorption coefficients as expected for the presence of one (1), two (2), and four (3) naphthyl chromophoric groups. The fluorescence spectra, however, are quite different from that of naphthalene. The naphthalene-type fluorescence (λ_max = 337 nm) is strongly quenched, particularly for compounds 1 and 2 which also exhibit a broad emission band in the visible region (λ_max ≈ 480 nm) assigned to a low lying charge-transfer excited state. In the case of compound 3, a quenched naphthalene-type band is accompanied by weak exciplex and excimer emissions. Upon titration with CF₃SO₃H, the charge transfer bands of 1 and 2 and the exciplex emission of 3 disappear and the naphthalene-type bands regain intensity. Titration plots show that in compounds 2 and 3 the protonation of the two nitrogens occurs stoichiometrically in two distinct steps. Titration with Zn²⁺ gives rise to 2.Zn²⁺ and 3.Zn²⁺ complexes. This article is dedicated to Professor Dedier Astruc.     

Male-Produced Aggregation Pheromone Compounds from the Eggplant Flea Beetle (Epitrix fuscula): Identification, Synthesis, and Field Biossays

Volatiles from the eggplant flea beetle, Epitrix fuscula Crotch (Coleoptera: Chrysomelidae), feeding on host foliage, were investigated. Six male-specific compounds were detected and were identified through the use of mass spectrometry, nuclear magnetic resonance (NMR) spectrometry, chiral and achiral gas chromatography, high-performance liquid chromatography, electrophysiology (gas chromatography-electroantennography, GC–EAD), and microchemical tests. The two most abundant of the six compounds were (2E,4E,6Z)-2,4,6-nonatrienal (1) and (2E,4E,6E)-2,4,6-nonatrienal (2). The other four compounds, present in minor amounts, were identified as himachalene sesquiterpenes; two of these, 3 and 4, were hydrocarbons and two, 5 and 6, were alcohols. All four sesquiterpenes were previously encountered from male flea beetles of Aphthona spp. and Phyllotreta cruciferae. Synthetic 1 and 2 matched the natural products by GC retention times, mass spectra, and NMR spectra. Sesquiterpenes 3–6 similarly matched synthetic standards and natural samples from the previously studied species in all ways, including chirality. Both natural and synthetic 1 and 2 gave positive GC–EAD responses, as did sesquiterpenes 3, 5, and 6. Field trials were conducted with a mixture of 1 and 2, and the baited traps were significantly more attractive than control traps to both male and female E. fuscula. The E. fuscula pheromone has potential for monitoring or controlling these pests in eggplants.Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the Department of Agriculture.     

Syntheses of female sex pheromone precursors of pine sawfly species and of some structurally related methyl-branched long-chain 2-alkanols

3,7-Dimethyl-2-undecanol, 3,7,9-trimethyl-2-tridecanol, and 3,7, 11-trimethyl-2-tridecanol were synthesized as racemic mixtures in moderate yields. The alcohols are known precursors of the female sex pheromones of the pine sawfly species Diprion nipponica, Macrodiprion nemoralis, and Microdiprion pallipes, respectively. Stereoisomeric mixtures of 3,8,12-trimethyl-2-tridecanol, erythro-(2R,3R,11R/S)-3,11-dimethyl-2-tetradecanol, 3,5-dimethyl-2-tetradecanol, and 5,7-dimethyl-2-tetradecanol, structurally related to sex pheromone alcohol precursors of pine sawfly species, were also synthesized in moderate yields. The key reaction in the syntheses was the ring opening of -butyrolactones by using different alkyl lithiums as nucleophiles.     

Studies on peroxidized lipids. VI. Fluorescent products derived from the reaction of primary amines,malonaldehyde and monofunctional aldehydes

Monofunctional aldehydes such as acetaldehyde,n-propylaldehyde,n-butylaldehyde,n-hexylaldehyde,n-heptylaldehyde and benzaldehyde affected the reaction between primary amines and malonaldehyde. While the reaction of primary amines and malonaldehyde at pH 7 produced fluorescent 4-methyl-1,4-dihydropyridine-3,5-dicarbaldehydesIa-f, the reaction of the primary amines, malonaldehyde and the aldehydes listed above gave fluorescent 4-substituted 1,4-dihydropyridine-3,5-dicarbaldehydesIIa-j. The primary amines used for this reaction included alkylamines, amino acids and alkanolamines. The optimal ratio of the amine, malonaldehyde and the aldehyde was 1:2:1–2, at which compoundsII were produced quantitatively. Peroxidized lipids which may contain malonaldehyde and other aldehydes could react with the primary amines to produce highly fluorescentII. Fluorescence spectra ofII showed excitation maxima at 386–403 nm and emission maxima at 444–465 nm in phosphate similar to those ofI. The spectra of these 1,4-dihydropyridinesI andII were roughly similar to those of lipofuscin pigment, but they exhibited different characteristics in acid and alkaline media from those of lipofuscin pigment. CompoundsII may be useful as model compounds to elucidate the chemical structure of lipofuscin pigment.     

Reinvestigation of anhydroserricornin, (2S,3S)-2,6-diethyl-3,5-dimethyl-3,4-dihydro-2H-pyran,as a sex pheromone component for male cigarette beetle

Reinvestigation of the pheromonal activity of anhydroserricornin, (2S,3S)-2,6-diethyl-3,5-dimethyl-3,4-dihydro-2H-pyran, showed that the magnitude of its activity was less than 1/10³ of that of serricornin, 7-hydroxy-4,6-dimethyl-3-nonanone, the sex pheromone of the cigarette beetleLasioderma serricorne (F.). Neither a synergistic nor an inhibitory effect of anhydroserricornin addition on the action of serricornin was observed.     

Exocrine secretions of the andromeda lace bugStephanitis takeyai (Hemiptera: Tingidae)

The four major components of the setal exudate of nymphs of the andromeda lace bug,Stephanitis takeyai, were identified. They are 7-hydroxy-3-nonylchromanone1, the novel 3,5-dihydroxy-2-dodecanoylcyclohex-2-en-1-one2,2,6-dihydroxydodecanophenone3, and its 3-hydroxy derivative4. Only three species ofStephanitis commonly occur in the United States; withS. takeyai we have now identified the major compounds secreted by each of these species. The individual species of the genus are chemotaxonomically distinct and are characterized by the oxidation states of the secreted compounds.     

Alkyldimethylpyrazines in the Defensive Spray of <Emphasis Type="Italic">Phyllium westwoodii</Emphasis>: A First for Order Phasmatodea

Phyllium westwoodii is a phasmid insect (Order Phasmatodea) belonging to the Family Phylliidae (leaf insects). These rather large and ornate creatures are known for their morphological resemblance to plant leaves for camouflage. Pyrazines are a common class of compounds used or produced by a wide variety of organisms, even humans. When an individual of P. westwoodii is disturbed, it sprays an opaque liquid from a pair of prothoracic glands, which are utilized by other phasmid species for defense. The current study has found that this liquid contains glucose and a mixture of 3-isobutyl-2,5-dimethylpyrazine, 2,5-dimethyl-3-(2-methylbutyl)pyrazine, and 2,5-dimethyl-3-(3-methylbutyl)pyrazine. This is the first report of pyrazines found in the defensive gland spray of phasmid insects, and the first chemical analysis of glandular material from family Phylliidae.     

Chemistry of venom alkaloids in the antMegalomyrmex foreli (Myrmicinae) from Costa Rica

Chemical analysis of the venom of the myrmicine antMegalomyrmex foreli from Costa Rica revealed the presence of four major alkaloidal components. Two of these, 2-butyl-5-(E, 1-heptenyl)-5-pyrroline (3) and 2-butyl-5-(E, E, 1,3-heptadienyl)-5-pyrroline (4), constitute a new functional class of ant venom alkaloids, whose structures were assigned from their spectral and chemical behavior and unambiguous syntheses. The function of these compounds is suggested by field observations of the behavior ofM. foreli, its sting morphology, and the relative toxicity of 3 and 4 against termite workers.     

A macrocyclic ligand 5,14-dihydro-6,15-dimethyl-8,17-diphenyldibenzo-[b,i][1,4,8,11]tetraazacyclotetradecine and its nickel(II) complex: Syntheses, reaction mechanism and structures

The template reaction of o-phenylenediamine, 1-benzoylacetone and nickelous acetate tetrahydrate results in two structure isomers, 6,17-dimethyl-8,15-diphenyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecinatonickel (II) (2) and 6,15-dimethyl-8,17-diphenyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecinatonickel (II) (4). However, the latter has been neglected in the previous research because of its low yield in the template reaction. The mechanism of this template reaction is discussed. Though the steric hindrance between the phenyl ring and the benzo ring in 2 is greater than that in 4, the intermediate of the former shows better structural stability than that of the latter, leading to obviously higher final yield of 2 compared with that of 4. n-Butyl alcohol is used artfully to separate the crude product of the template reaction into almost pure 2 and a mixture of 2 and 4 in a mole ratio of 1:5. The free base of 2, 5,14-dihydro-6,17-dimethyl-8,15-diphenyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine (1), can be synthesized by demetalization of 2 with gaseous HCl. The same treatment to the mixture of 2 and 4 in a mole ratio of 1:5 leads to the free base of 4, 5,14-dihydro-6,15-dimethyl-8,17-diphenyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine (3). The neglected macrocyclic compounds 3 and 4 have been characterized unambiguously and their single-crystal structures have also been determined by X-ray diffraction analysis for the first time.     

Isolation of the diterpenoids, ent-kauran-16alpha-ol and ent-atisan-16alpha-ol, from sunflowers, as oviposition stimulants for the banded sunflower moth, Cochylis hospes

Two diterpenoid alcohols, ent-kauran-16-ol (1) and ent-atisan-16-ol (2), were isolated from pre bloom (R3-R4 stage) sunflower heads as oviposition stimulants for the banded sunflower moth, Cochylis hospes. Fractionation of a sunflower head extract, by normal-phase flash column chromatography, resulted in an early eluting fraction exhibiting significant activity in an egg-laying bioassay. Compounds 1 and 2, along with ent-trachyloban- 19-oic acid (3) and ent-kaur-16-en-19-oic acid (4), were isolated as the major components of this fraction and identified by their NMR and mass spectra. The purified compounds were individually tested for ovipositional activity in dose-response bioassays. In these bioassays, compounds 1 and 2 gave linear dose responses, with increasing numbers of eggs laid as the dosage of either increased. Compounds 3 and 4 failed to stimulate significant egg-laying at any of the dosages tested. A factorial design bioassay, using compounds 1 and 2, showed that 1 was relatively more stimulatory than 2, and that there was no synergistic effect on oviposition when the two compounds were combined.     

Volatiles from whitefly-infested plants elicit a host-locating response in the parasitoid,Encarsia formosa

The blend of volatile compounds emitted by bean plants (Phaseolus vulgaris) infested with greenhouse whitefly (Trialeurodes vaporariorum) has been studied comparatively with undamaged plants and whiteflies themselves. Collection of the volatiles and analysis by gas chromatography revealed more than 20 compounds produced by plants infested with whitefly. Of these, 4 compounds, (Z)-3-hexen-1-ol, 4,8-dimethyl-1,3,7-nonatriene, 3-octanone, and one unidentified compound were emitted at higher levels than from the undamaged control plants. Synthetic (Z)-3-hexen-1-ol, 4,8-dimethyl-1,3,7-nonatriene, or 3-octanone all elicited a significant increase in oriented flight and landing on the source by the parasitoid, Encarsia formosa, in wind tunnel bioassays. Two-component mixtures of the compounds and the three-component mixture all elicited a similar or, in most cases, a better response by the parasitoid, the most effective being a mixture of (Z)-3-hexen-1-ol and 3-octanone. These results demonstrate that E. formosa uses volatiles from the plant-host complex as olfactory cues for host location.     

Volatile compounds in anal gland of Siberian weasels (Mustela sibirica) and steppe polecats (M. eversmanni)

The volatile constituents in anal gland secretions of two sympatric Mustela species, the Siberian weasel (M. sibirica) and steppe polecat (M. eversmanni), were studied by the headspace technique, followed by gas chromatography–mass spectrometry (GC-MS) analysis. Nine sulfur-containing compounds were identified. They were 2,2-dimethylthietane, (Z)- or (E)-2,4-dimethylthietane, (E)-2,3-dimethylthietane, 2-ethylthietane, (E)-2-ethyl-3-methylthietane, (Z)-2-ethyl-3-methylthietane, 2-propylthietane, 3,3-dimethyl-1,2-dithiacyclopentane, and (Z)-3,4-dimethyl-2,2-dithiacyclopentane. Among them, (E)-2-ethyl-3- methylthietanes, (Z)-2-ethyl-3-methylthietanes, and (Z)-3,4-dimethyl-1,2-dithiacyclopentane were present in the polecat but not in the weasel. The predominant compound was 2,2-dimethylthietane in the weasel and (E)- or (Z)-2,4-dimethylthietane in the polecat. These differences were consistent between the two species, regardless of sex and age and, therefore, could possibly be used for species recognition. In the weasel, 2-ethylthietane was found only in the female, and the relative abundance of several compounds was significantly different between males and females. In the polecat, although no sex-specific volatile compounds were found, males and females differed in the relative abundance of several of the compounds. In both species, the relative abundance of some compounds varied with age. We conclude that these volatile compounds can be used to communicate information about species, sex, and age.