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Chemical communication is ubiquitous. The identification of conserved structural elements in visual and acoustic communication is well established, but comparable information on chemical communication displays (CCDs) is lacking. We assessed the phenotypic integration of CCDs in a meta‐analysis to characterize patterns of covariation in CCDs and identified functional or biosynthetically constrained modules. Poorly integrated plant CCDs (i.e. low covariation between scent compounds) support the notion that plants often utilize one or few key compounds to repel antagonists or to attract pollinators and enemies of herbivores. Animal CCDs (mostly insect pheromones) were usually more integrated than those of plants (i.e. stronger covariation), suggesting that animals communicate via fixed proportions among compounds. Both plant and animal CCDs were composed of modules, which are groups of strongly covarying compounds. Biosynthetic similarity of compounds revealed biosynthetic constraints in the covariation patterns of plant CCDs. We provide a novel perspective on chemical communication and a basis for future investigations on structural properties of CCDs. This will facilitate identifying modules and biosynthetic constraints that may affect the outcome of selection and thus provide a predictive framework for evolutionary trajectories of CCDs in plants and animals., The project was supported by the Graduate School ‘Evolutionary Networks: Organisms, Reactions, Molecules’ (E‐Norm) of the Heinrich‐Heine‐University, Düsseldorf, Germany, the Max Planck Society and the Deutsche Forschungsgemeinschaft (DFG JU 2856/1‐1 and DFG JU 2856/2‐2).

The European corn borer (ECB) Ostrinia nubilalis is a widespread pest of cereals, particularly maize. Mating disruption with the sex pheromone is a potentially attractive method for managing this pest; however, chemical synthesis of pheromones requires expensive starting materials and catalysts and generates hazardous waste. The goal of this study was to develop a biotechnological method for the production of ECB sex pheromone. Our approach was to engineer the oleaginous yeast Yarrowia lipolytica to produce (Z)-11-tetradecenol (Z11-14:OH), which can then be chemically acetylated to (Z)-11-tetradecenyl acetate (Z11-14:OAc), the main pheromone component of the Z-race of O. nubilalis. First, a C14 platform strain with increased biosynthesis of myristoyl-CoA was obtained by introducing a point mutation into the α-subunit of fatty acid synthase, replacing isoleucine 1220 with phenylalanine (Fas2pI1220F). The intracellular accumulation of myristic acid increased 8.4-fold. Next, fatty acyl-CoA desaturases (FAD) and fatty acyl-CoA reductases (FAR) from nine different species of Lepidoptera were screened in the C14 platform strain, individually and in combinations. A titer of 29.2 ± 1.6 mg L-1 Z11-14:OH was reached in small-scale cultivation with an optimal combination of a FAD (Lbo_PPTQ) from Lobesia botrana and FAR (HarFAR) from Helicoverpa armigera. When the second copies of FAD and FAR genes were introduced, the titer improved 2.1-fold. The native FAS1 gene's overexpression led to a further 1.5-fold titer increase, reaching 93.9 ± 11.7 mg L-1 in small-scale cultivation. When the same engineered strain was cultivated in controlled 1 L bioreactors in fed-batch mode, 188.1 ± 13.4 mg L-1 of Z11-14:OH was obtained. Fatty alcohols were extracted from the biomass and chemically acetylated to obtain Z11-14:OAc. Electroantennogram experiments showed that males of the Z-race of O. nubilalis were responsive to biologically-derived pheromone blend. Behavioral bioassays in a wind tunnel revealed attraction of male O. nubilalis, although full precopulatory behavior was observed less often than for the chemically synthesized pheromone blend. The study paves the way for the production of ECB pheromone by fermentation.

Pyrazines are well-known natural products that are present in bacterial odours and food flavouring agents and are used as insect pheromones. Recently, a number of hydroxymethylpyrazines have been identified as thynnine wasp pheromones and orchid semiochemicals that are essential for pollination in sexually deceptive plants. These compounds are present in low amounts in complex blends, making GC-MS (including high-resolution techniques) the method of choice for their structure elucidation. We report the EI mass spectra for 14 representative compounds and have found that based on characteristic fragmentations, it is possible to distinguish between different positional isomers of hydroxymethylpyrazines. The presence or absence of either [M - 17]+ , [M - 18]+· or [M - 19]+ fragment species provides characteristic information to allow the distinction between the different isomers. Considering the importance of pyrazines as a group of bioactive natural products, and the recent findings of biological activity for hydroxymethylpyrazines, our results presented here will aid the identification of these compounds in other biological systems. Copyright © 2015 John Wiley & Sons, Ltd.

The use of insect sex pheromones to limit specifically targeted pest populations has gained increasing popularity as a viable, safe, and environmentally friendly alternative to insecticides. While broad-spectrum insecticides are toxic compounds that have been shown to adversely affect human health,[1] extensive studies have shown that insect pheromones are nontoxic and safe for human consumption at the levels used in pest control practices.[2] Female sex pheromones are mainly employed in pest control in a process termed mating disruption. This involves dispersing pheromones over a large area, overloading the sensory organs of male insects and preventing them from locating and mating with females who are releasing a much smaller amount of the same pheromone blends; this strategy has proven to reduce specific insect populations dramatically.[3] To date, the United States Environmental Protection Agency (EPA) has approved approximately twenty lepidopteran female sex pheromones as active ingredients for pest control.[2]

We present pheromone measurements of metal-oxide gas sensors in a laboratory setup using a ‘selective odorant measurement of a multi-sensor array’. The array was equipped with commercial gas sensors and measured with constant temperatures and a temperature cycle to increase the sensitivity. To compare and to calibrate the measurement of insect pheromones, we used a portable GC-MS with an electro-antennographic detection system for insect antennae. In order to reach a proof of principles for the intended use of the system for in situ analyses in viticulture and the development of a portable biosensor, we tested the sensors with the main component E7,Z9-Dodecadien-1-yl acetate of the pheromone of the grapevine moth (Lobesia botrana).

The potential use of polyurea microcapsules, as ‘release carriers’ for insect pheromones, has been demonstrated. (Z)-11-hexadecenyl acetate (Z11-16:Ac), the major sex pheromone component of several Noctuidae species, was used as the model molecule. The coating material's ability to release the pheromone was initially studied by the solid-phase micro-extraction technique. Polyurea microcapsules released Z11-16:Ac relatively slowly, with a duration of approximately 1 month, as it was determined under both laboratory and semi-field conditions. Preliminary laboratory bioassays revealed a satisfactory attraction of Sesamia males, at doses of 50 and 500 mg of dried microcapsules containing the aforementioned pheromone. Almost all male insects tested initiated flight and among them 40.2–49.4% successfully contacted the pheromone source. The preparation of polyurea microcapsules needs further refinement as to increase release duration; nevertheless, these results demonstrate strong potential for the future use of polyurea microcapsules as part of integrated insect control programmes.

Research from the last 20 years on the use of ozonolysis of cyclic and acyclic mono- and dienes and aromatic compounds in various steps of the total synthesis of insect pheromones and juvenoids was reviewed.

A simple and convenient synthesis of five important insect pheromones by means of Baylis–Hillman adducts is described, i.e., of (2E,4S)-2,4-dimethylhex-2-enoic acid (1), a mandibular-gland secretion of the male carpenter ant in the genus Camponotus, of (+)-(S)-manicone (2) and (+)-(S)-normanicone (3), two mandibular-gland constituents of Manica ants, and of (+)-dominicalure-I (6) and (+)-dominicalure-II (7), two aggregation pheromones of the lesser grain borer Rhyzopertha dominica (F). For the first time, the potential of the Baylis–Hillman chemistry for the stereoselective synthesis of trisubstituted olefins was successfully applied to the synthesis of these pheromone compounds.

Enantioselective synthesis is a central component of research on the effect of chirality on the relationships between pheromone structure and pheromone bioactivity. The syntheses of stegobinone, the drugstore beetle pheromone, and frontalin, a bark beetle pheromone, are reported as examples of stereocontrolled synthesis. Chirality governs the biodiversity of pheromone perception, as illustrated by the discussion on the relationships between absolute configuration and pheromone activity. Chirality 10:578–586, 1998. © 1998 Wiley-Liss, Inc.

A simple and efficient asymmetrical synthesis was performed of a convenient bifunctional building block, methyl (R)-5,5-dimethoxy-3-methylpentanoate and its (S)-enantiomer. The possibility was shown of its application to the synthesis of insect pheromones.

This review considers the synthetic possibilities of monoterpene ketones, such as (R)-(+)- and (S)-(-)-pulegones, (-)-menthone, (R)-(-)- and (S)-(+)-carvones, (2R,5S)-dihydrocarvone, (S)-(+)- and (R)-(-)-camphors, (R)-(-)-nopinone, (R)-(+)- and (S)-(-)-verbenones by the examples of synthesis of optically pure and enantiomerically enriched insect pheromones.

Chemistry and biology of oxygen heterocycles as insect pheromones are reviewed referring to exo-brevicomin, disparlure, japonilure and olean. Synthesis of koninginin A, a microbial metabolite, is discussed. Two azetidine alkaloids, penaresidin A and penazetidine A, were synthesized.

Mori's synthetic works on bioactive natural products in general and pheromones in particular started about 40 years ago to establish their absolute configurations and also to clarify their stereochemistry-bioactivity relationships. Results indicate that bioactive natural products are not always enantiomerically pure, and the stereochemistry-bioactivity relationships are not simple but complicated. For example, neither (R)- nor (S)-sulcatol, the aggregation pheromone of an ambrosia beetle, is behaviorally bioactive, whereas their mixture is active. In the case of olean, the sex pheromone of the olive fruit fly, its (R)-isomer is active against the males and the (S)-isomer is active against the females. Recent synthesis of two new insect pheromones is discussed to illustrate the modern methods in enantioselective synthesis.

Controlled alkylation of deprotonated N -Acyclohexyl-1-cyclopropylethylidene imine 1 or its condensation with aldehydes lead efficiently to the saturated ( 3 ) or conjugated ( 5 ) cyclopropyl ketones respectively, the latter being key intermediates in short stereospecific syntheses of some transoid Lepidoptera insect pheromones.

1. Introduction During the past two decades, there has been a rapidly growing interest in the field of intra- and interspecific chemical communication. Insect pheromones in particular have been intensely studied with respect to their potential use as a component of integrated pest management.1 Structural identification and chemical synthesis of these so-called “semiochemicals” have developed in harmony with the biological research evaluating structure-activity relationships. Most of the pheromones identified, studied, and synthesized come from the order Lepidoptera: very often these pheromones consist of long-chain olefinic compounds in which regio- and cis/trans-isomerism determine their biological activity. Several well documented reviews have appeared, emphasizing both coupling of alkyl halides or similar electrophilic substrates with metallo-organic reagents (“Wurtz-chemistry”) and carbonyl olefination, such as the Wittig reaction and its huge variety of modifications for regio- and stereoselective C-...

A combination of the Homer–Emmons synthesis of alkyl 2,4-dienoates with their hydrogenation over complex L·Cr(CO) 3 catalysts (L = arene or 3CO) provides a versatile, stereocontrolled approach to olefins with a homoallylic pattern of functional substitution, such as certain insect pheromones or ( Z )-prenylated arenes analogous to the “left-side” moiety of bifurcarenone.

Enantioselective synthesis of three insect pheromones, (5 Z , 13 S )-5-tetradecen-13-olide, (9 R )-decan-9-olide, and ( S )-2-acetoxytridecane, has been achieved by using Mn-salen catalyzed asymmetric epoxidation as a key step.

New and enantioselective syntheses of three known insect pheromones - faranal 1, matsuone 2 and olean 3 - were achieved. Lurlene 4, the sex pheromone of the green flagellate Chlamydomonas allensworthii, was synthesized by employing a palladium-catalyzed carbon-carbon bond formation reaction as the key step. Several analogs of blattellastanoside A 5, the aggregation pheromone of the German cockroach, were synthesized, and the fluorinated analog 74 was found to be biologically more potent than the natural pheromone 5.

Chemistry and biology of oxygen heterocycles as insect pheromones are reviewed referring to exo-brevicomin, disparlure, japonilure and olean. Synthesis of koninginin A, a microbial metabolite, is discussed. Two azetidine alkaloids, penaresidin A and penazetidine A, were synthesized.

Enantioselective synthesis is a central component of research on the effect of chirality on the relationships between pheromone structure and pheromone bioactivity. The syntheses of stegobinone, the drugstore beetle pheromone, and frontalin, a bark beetle pheromone, are reported as examples of stereocontrolled synthesis. Chirality governs the biodiversity of pheromone perception, as illustrated by the discussion on the relationships between absolute configuration and pheromone activity. Chirality 10:578–586, 1998. © 1998 Wiley-Liss, Inc.

Syntheses carried out with participation of the author of terpenoids, polyprenols, prenylcarboxylic acids, insect pheromones, and juvenoids based on α,ω-dicarbonyl 1,5-unsaturated isoprenoid compounds with (Z)- and (E)-configurations, obtained by controlled ozonolysis of isoprene cyclic oligomers and polyisoprene rubbers, are considered.

The E-isomer selectivity of the Horner-Wadsworth-Emmons olefination of aldehydes to form α-methyl- or α-ethyl-α,β-unsaturated esters has been improved by using lithium tert-butoxide as the base, triethyl-2-phosphonopropionate or triethyl-2-phospho-nobutyrate as the phosphonate, an aldehyde, and hexane as the reaction solvent. Greater E-isomer selectivity was observed in the formation of α-methyl-α,β-unsaturated esters than α-ethyl-α,β-unsaturated esters. These compounds are useful intermediates for the synthesis of insect pheromones and natural products.

The synthetic utility of the readily separated epoxides, diols, epoxydiols and tetrols of high enantiomeric excesses, obtained by hydrolytic kinetic resolution (HKR) of functionalised mono- and bisepoxides with (salen)Co(OAc) complexes, is demonstrated by their efficient transformations to important insect pheromones.

Fettsauren aus naturlichen Fetten und Olen konnen als Ausgangsmaterial fur die Partialsynthese einer Vielzahl biologisch aktiver Lipide dienen, insbesondere wenn man auch enzymatische Verfahren und Biotransformation (Biokonversion) in die Semisynthesen einbezieht. Die so gewonnenen Produkte sind von hohem Wert; sie konnen im medizinisch-pharmazeutischen Bereich sowie in Nahrungsmittelindustrie und Landwirtschaft eingesetzt werden. In diesem Beitrag wird vor allem auf zwei Produktgruppen, die in jungster Zeit Bedeutung erlangt haben, eingegangen – namlich Etherlipide (Etherglycerolipide) und Insektenpheromone. Preparation of Biological Active Lipids by Semi-Synthesis and Biotransformation Fatty acids derived from natural fats and oils are useful starting materials for the semi-synthetic preparation of many biologically active lipids. Enzymatic derivatization and biotransformation (bioconversion) may also be included in the semi-synthesis of bioactive compounds. Valuable products formed by such processes can be used in medicine and pharmacy as well as food industry and agriculture. This contribution concentrates on two subjects – ether lipids (ether glycerolipids) and insect pheromones – which are of great current interest in medicine and agriculture.

The synthesis of insect pheromones published in the period 2005-2007 is reviewed. A total of 66 compounds from different insect orders and belonging to different structural classes were included.

The review of works of the authors devoted to the synthesis of low-molecular bioregulators with the use of unsaturated sugars is presented. The schemes of synthesis of insect pheromones and acetogenins and glycophosphingolipids on the basis of glycals are discussed. The pathways of synthesis of triterpene 2-deoxy-α-glycosides are shown. The synthesis of prostanoids from levoglucosenone is considered.

The asymmetric total synthesis of naturally occurring insect pheromones, (R)-4-dodecanolide and (S)-5-hexadecanolide has been achieved in a simple and efficient way with high yields.

Diastereoisomeric epimers at C1′ of 4-(1-methyl-2-oxo-butyl)-2-butenolide, and the corresponding saturated γ-lactones, were synthesized by hydrolysis of 1-methoxy-8-oxabicyclo[3.2.1] oct-6-en-3-one, under acidic conditions. These butenolides are interesting synthetic building blocks, precursors of biologically active natural products like insect pheromones. Their formation could be explained by a cleavage at the C1–C2 bond of the oxabicyclic precursor. On the basis of the experimental data we have proposed a mechanism of hydrolytic cleavage which is formally an intramolecular reverse Dieckmann process.

An expeditious three-step synthesis of a mixture of stereoisomers of 5,9-dimethylpentadecane 1, the sexual pheromone of the coffee leaf miner Leucoptera coffeella, is described. The route employs an unsymmetrical double Wittig olefination to build the carbon skeleton of the molecule, as the key reaction. The bis-phosphonium salt 3, derived from 1,3-dibromopropane 2, reacted ‘one-pot’ with the ketones 2-octanone and 2-hexanone, affording the asymmetric diene 4. This was readily hydrogenated over Pd/C, furnishing pheromone 1 in 54% overall yield. Synthetic 1 showed high biological activity when tested in field experiments.