Synthesis Of Pheromone Research Articles

Monoterpene Emissions from Lodgepole and Jack Pine Bark Inoculated with Mountain Pine Beetle‐Associated Fungi

Relative monoterpene levels were analyzed from bark samples of lodgepole pine, jack pine, and their hybrids inoculated with mountain pine beetle (MPB)–associated fungi (Leptographium longiclavatum, Grosmannia clavigera, and Ophiostoma montium). Lodgepole pine showed the largest changes in relative emissions as a result of fungal inoculation. The relative emission of β‐phellandrene increased with fungal inoculation, making it the most abundant monoterpene for inoculated samples. Relative emissions of limonene and α‐pinene decreased in inoculated lodgepole pine. Lodgepole (5.6) and jack (146) pine differed in the ratio of α‐pinene to myrcene; two monoterpenes involved in pheromone synthesis by the MPB. These differences may contribute to the attractiveness of the two species as hosts for MPB; with jack pine potentially less attractive than lodgepole pine. Fungal inoculation reduced α‐pinene:myrcene ratios in lodgepole pine, which suggests one possible mechanism by which the fungi benefit the beetle.

Identification, Synthesis, and Bioassay of a Male-Specific Aggregation Pheromone from the Harlequin Bug, Murgantia histrionica

Sexually mature male harlequin bugs produced a sex-specific compound, identified as one of the stereoisomers of the sesquiterpene epoxyalcohol 4-[3-(3,3-dimethyloxiran-2-yl)-1-methylpropyl]-1-methylcyclohex-2-en-1-ol (henceforth murgantiol), a compound with four chiral centers and 16 possible stereoisomers. Production of the compound was highest during the middle of the day. Individual virgin male bugs in separate containers produced the compound at a higher rate than virgin males in groups. The carbon skeleton was verified by synthesis of several mixtures which, in total, contained all possible isomers, one of which matched the insect-produced compound. The relative and absolute configurations of the insect-produced compound remain to be determined. In laboratory bioassays, insect-produced and synthetic murgantiol attracted harlequin bugs of both sexes, suggesting that murgantiol is a male-produced aggregation pheromone, analogous to those found in a number of other phytophagous bug species.

Chemoenzymatic Synthesis of the Aggregation Pheromones (S)-2-methyl- 4-octanol and (4S, 2E)-6-methyl-2-hepten-4-ol

In this work we synthesized the aggregation pheromones (S)-2-methyl-4-octanol and (4S, 2E)-6-methyl-2- hepten-4-ol in high enantiomeric excess applying as the key step an enzymatic resolution of 5-methyl-1-hexyn-3-ol. Keywords: Aggregation pheromones, (S)-2-methyl-4-octanol, (4S, 2E)-6-methyl-2-hepten-4-ol, chemoenzymatic synthesis

パラジウム錯体触媒による置換アレン類の立体選択的合成法の開発とその応用

A novel Pd-catalyzed reaction of a 2-halo- or 2-trifloxy-l, 3-butadiene derivative with a soft nucleophile is developed. The reaction proceeds via an exo-alkylidene-π-allylpalladium intermedi-ate in a formal SN2' fashion to give an allenic compound exclusively. A variety of soft nucleophiles, such as malonates, phenoxides, and imides, are applicable to the reaction, and thus a wide range of functionality can be introduced to the products. The reaction is extended into an asymmetric counterpart and axially chiral allenes are prepared with up to 93% ee by the use of chiral palladium catalysts. A formal total synthesis of an insect pheromone is achieved using the Pd-catalyzed asymmetric reaction as a key step. The Pd-catalyzed reaction also enables to prepare axially chiral (allenylmethyl) silanes and allenylsilanes in optically active forms. Reactions of these silylallenes with appropriate electrophiles proceed via SE', pathways and the allenic axial chirality is efficiently transferred to stereogenic carbon centers in the SE', products.

Synthesis of the Sex Pheromone of the Obscure Mealybug, the First Example of a New Class of Monoterpenoids.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

The pheromone biosynthesis activating neuropeptide (PBAN) receptor of Heliothis virescens: Identification, functional expression, and structure–activity relationships of ligand analogs

Pheromone biosynthesis activating neuropeptide (PBAN) promotes synthesis and release of sex pheromones in moths. We have identified and functionally expressed a PBAN receptor from Heliothis virescens (HevPBANR) and elucidated structure–activity relationships of PBAN analogs. Screening of a larval CNS cDNA library revealed three putative receptor subtypes and nucleotide sequence comparisons suggest that they are produced through alternative splicing at the 3′-end. RT-PCR amplified preferentially HevPBANR-C from female pheromone glands. CHO cells expressing HevPBANR-C are highly sensitive to PBAN and related analogs, especially those sharing the C-terminal pentapeptide core, FXPRLamide (X = T, S or V). Alanine replacements in the C-terminal hexapeptide (YFTPRLamide) revealed the relative importance of each residue in the active core as follows: R 5 > L 6 > F 2 ≫ P 4 > T 3 ≫ Y 1. This study provides a framework for the rational design of PBANR-specific agonists and/or antagonists that could be exploited for disruption of reproductive function in agriculturally important insect pests.

Scented Males and Choosy Females: Does Male Odor Influence Female Mate Choice in the Mediterranean Fruit Fly?

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), displays a lek mating system characterized by a high level of female discrimination among potential mates. The basis of female choice is not understood, but recent studies indicate that male exposure to the aroma of certain plant structures or essential oils may increase mating success. In particular, exposure to the aroma of ginger root oil (GRO) enhances male mating frequency, and several sterile-male release programs against C. capitata have incorporated 'aromatherapy' (large-scale exposure of pre-release insects to GRO) to increase the effectiveness of control efforts. We investigated the mechanism underlying female preference for GRO-exposed males. Two sets of experiments were conducted. In the first, we monitored female attraction to (1) freshly killed flies, or (2) paper discs that contained hexane extracts from varying treatments. In these tests, females were sighted more often (1) near GRO-exposed than non-exposed males (even when the males were visually concealed) and (2) near extracts from GRO-exposed than non-exposed males. These findings suggest a 'perfume effect', whereby female mate choice is mediated by olfactory differences. In the second set, we compared (1) mate choice between intact females and females from which both antennae had been surgically removed, and (2) mating success between intact males and males from which both antennae had been surgically removed before GRO exposure. Intact females preferred GRO-exposed males, whereas females lacking both antennae rarely mated and showed no preference between GRO-exposed and non-exposed males. In the opposite treatment (intact females but surgically altered males), GRO-exposed males lacking both antennae mated as frequently as GRO-exposed intact males. These data suggest that female choice was dependent on olfactory perception of male odor but that male mating success did not depend on olfactory perception of GRO aroma, suggesting, in turn, that GRO conferred a mating advantage through an external phenomenon (possibly alteration of cuticular scent) rather than through internal processing (pheromone synthesis).

The Reactivity of Epoxides with Lithium 2,2,6,6‐Tetramethylpiperidide in Combination with Organolithiums or Grignard Reagents.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Stereospecific synthesis of the sex pheromone of the passionvine mealybug, Planococcus minor

A short and completely stereospecific synthesis of ( E)-2-isopropyl-5-methyl-2,4-hexadienyl acetate, the very recently identified sex pheromone of the passionvine mealybug Planococcus minor, is described. In the key step, CuI-catalyzed anti-addition of a Grignard reagent to a propargyllic alcohol intermediate gave the required trisubstituted alkene with 100% regio- and stereospecificity. The stereochemical purity of the pheromone is critically important because the ( Z)-isomer is a powerful behavioral antagonist.

Synthesis of (R)‐Japonilure and (4R,9Z)‐9‐Octadecen‐4‐olide, Pheromones of the Japanese Beetle and Currant Stem Girdler

Asymmetric total synthesis of the sex pheromones of Japanese beetle and currant stem girdler, (R)‐japonilure (1) and (4R,9Z)‐9‐octadecen‐4‐olide (2), has been achieved.

Oxidation of Unsaturated Primary Alcohols and ω-Haloalkanols with 4-Acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium Tetrafluoroborate

Unsaturated primary alcohols and ω-haloalkanols, all applied in pheromone synthesis, are oxidized to the corresponding aldehydes using 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxo--ammonium tetrafluoroborate ( 1A). Three methods are compared with one another; oxidations with 1A and silica gel, oxidations with 1A in the presence of pyridine, and pyridinium chlorochromate (PCC).

Synthesis of the sex pheromone of the obscure mealybug, the first example of a new class of monoterpenoids

A diastereoselective synthesis of (1 R ∗,2 R ∗,3 S ∗)-1-acetoxymethyl-2,3,4,4-tetramethylcyclopentane, the sex pheromone of the obscure mealybug Pseudococcus viburni, is described. Key steps included the polyphosphoric acid-catalyzed cyclization of isobutyl methacrylate to form the core five-membered ring, and diastereoselective quenching of an enolate intermediate to give the thermodynamically less favored cis orientation of vicinal methyl groups in a cyclopentanone intermediate.

Enantioselective synthesis of α-benzyloxy-ω-alkenals: application to the synthesis of (+)- exo-brevicomin, (+)-iso- exo-brevicomin, and (−)-isolaurepan

The enantioselective synthesis of α-benzyloxy aldehydes containing a terminal alkene was carried out from chiral pool l-(+)-tartaric acid by employing the stereoselective reduction of a 1,4-diketone as the key step. The synthetic utility of these aldehydes was demonstrated in the synthesis of pine beetle pheromones (+)- exo-brevicomin, (+)-iso- exo-brevicomin and a formal synthesis of 2,7- cis-disubstituted oxepane (−)-isolaurepan.

Furanyl spiroketals as stereochemical relays in the synthesis of 1,9- anti diols: synthesis of insect pheromones

A suite of spiroketal insect pheromones ( 15 and 17a– d) has been synthesised in good yield and with very high levels of diastereoselectivity via furanyl spiroketals. Remote asymmetric induction is achieved under thermodynamic control. The use of furanyl spiroketals as temporary scaffolds in the synthesis of 1,9- anti diols has been demonstrated with the synthesis of the swede midge pheromone (2 S,10 S)-2,10-diacetoxyundecane 1. The enzymatic resolution of a C 2 symmetric 1,9- anti diol was used as a confirmation of diastereomeric purity.

Role of the ejaculatory bulb in biosynthesis of the male pheromone cis‐vaccenyl acetate in Drosophila melanogaster

In Drosophila melanogaster, the male ejaculatory bulb is the site of synthesis of a male-specific pheromone, cis-vaccenyl acetate, which functions as both an attractant and an anti-aphrodisiac. This long monounsaturated acetate is structurally similar to a number of shorter gland-synthesized moth pheromones. The cell monolayer that forms the Drosophila male ejaculatory bulb wall is responsible for the production and secretion of cis-vaccenyl acetate into the seminal fluid. When dissected bulbs were incubated with sodium [14-C]-acetate (or deuterated acetate), a labeled acetate ester was synthesized. The labeled acetate ester co-migrated with cis-vaccenyl acetate in thin layer chromatography. Incubation of the abdomens of males from which the ejaculatory bulbs had been removed, or the abdomens of females, with radiolabeled acetate did not yield any acetate ester, but did yield other lipid products, including hydrocarbons. When the isolated labeled acetate ester was hydrolyzed, no radioactive vaccenol was formed. This strongly suggests that the acetyl group is incorporated via a transacetylation reaction, but that the vaccenyl moiety is not synthetized in the blub. The transacetylation enzyme activity was localized in the microsomal subfraction of the bulb homogenate, and its affinity for vaccenol was not very different from that reported for monounsaturated alcohol substrates in moths.

The Reactivity of Epoxides with Lithium 2,2,6,6-Tetramethylpiperidide in Combination with Organolithiums or Grignard Reagents

The scope and limitations of lithium 2,2,6,6-tetramethylpiperidide (LTMP)-modified reductive alkylation of epoxides is detailed. A variety of organolithiums are added to terminal and 2,2-disubstituted epoxides in the presence of LTMP to generate alkenes in a completely regio- and highly stereoselective manner. Arylated alkenes, dienes, allylsilanes, and enynes are accessed using this procedure. The methodology is applied in the synthesis of the roller leaf moth pheromone, (3E,5Z)-dodecadienyl acetate. The corresponding reaction without LTMP has also been examined, and a study using deuterated epoxides provides insight into the mechanism. In the presence of LTMP, Grignard reagents are also shown to produce E-alkenes directly from epoxides.

Biocatalysis Applied to the Synthesis of Pheromones

Biocatalysis Applied to the Synthesis of Pheromones

Control of reproductive dominance by thethelytokygene in honeybees

Differentiation into castes and reproductive division of labour are a characteristics of eusocial insects. Caste determination occurs at an early stage of larval development in social bees and is achieved via differential nutrition irrespective of the genotype. Workers are usually subordinate to the queen and altruistically refrain from reproduction. Workers of the Cape honeybee (Apis mellifera capensis) do not necessarily refrain from reproduction. They have the unique ability to produce female offspring parthenogenetically (thelytoky) and can develop into 'pseudoqueens'. Although these are morphologically workers, they develop a queen-like phenotype with respect to physiology and behaviour. Thelytoky is determined by a single gene (th) and we show that this gene also influences other traits related to the queen phenotype, including egg production and queen pheromone synthesis. Using 566 microsatellite markers, we mapped this gene to chromosome 13 and identified a candidate locus thelytoky, similar to grainy head (a transcription factor), which has been shown to be highly expressed in queens of eusocial insects. We therefore suggest that this gene is not only important for determining the pseudoqueen phenotype in A. m. capensis workers, but is also of general importance in regulating the gene cascades controlling reproduction and sterility in female social bees.

Special Issue on the Magnetic and Electric Field Effects at the Micro- and Nano-Scale Systems and Flows in Material Processing

Special Issue on the Magnetic and Electric Field Effects at the Micro- and Nano-Scale Systems and Flows in Material Processing

Queen Sex Pheromone of the Slave-making Ant, Polyergus breviceps

Workers of the slave-making ant, Polyergus breviceps, raid nests of Formica ants and return with Formica pupae that mature into worker ants in the slave-makers' colony. These Formica workers then tend the Polyergus brood, workers, and reproductives. During raids in the mating season, winged virgin Polyergus queens accompany the workers in the raiding columns. During the raid, the virgin queens release a pheromone that attracts males that quickly mate with the queens. We report the identification, synthesis, and bioassay of the sex attractant pheromone of the queens as an approximately 1:6 ratio of (R)-3-ethyl-4-methylpentan-1-ol and methyl 6-methylsalicylate. The ants produce exclusively the (R)-enantiomer of the alcohol, and the (S)-enantiomer has no biological activity, neither inhibiting nor increasing attraction to blends of methyl 6-methylsalicylate with the (R)-enantiomer.