Stereoisomeric Separation of Derivatized 2-alkanols Using Gas Chromatography-Mass Spectrometry: Sex Pheromone Precursors Found in Pine Sawfly Species

Stereoisomers of long-chain secondary alcohols are used as sex pheromone precursors among pine sawflies and some species can be severe pine forest pests. To use their pheromone in environmentally friendly pest management, methods are needed that can determine the stereochemistry of the precursor alcohols. Combinations of 11 acid chloride derivatives and 10 GC columns were evaluated for separation of stereoisomers of 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol, 3,7-dimethyltridecan-2-ol, 3,7-dimethyltetradecan-2-ol, and 3,7-dimethylpentadecan-2-ol. Derivatization with (S)-2-acetoxypropionyl chloride in combination with a Chiraldex B-PA column separated all eight stereoisomers of 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol, and 3,7-dimethyltridecan-2-ol. A combination of two different derivatization methods was needed to separate all stereoisomers of the longer chained alcohols 3,7-dimethyltetradecan-2-ol and 3,7-dimethylpentadecan-2-ol. A female extract of the pine sawfly Neodiprion lecontei was also analyzed and the stereochemistry of the sex pheromone alcohol precursor was determined to be (2S,3S,7S)-3,7-dimethylpentadecan-2-ol at an amount of about 7 ng/female. This paper presents the first GC-MS separation of all eight stereoisomers of 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol, and 3,7-dimethyltridecan-2-ol in a single analytical run and also the first GC-MS determination of the stereochemistry of the sex pheromone precursor found in females of N. lecontei.     

New synthesis of ( E )-3,7-dimethyl-2,7-octadienylpropionate and ( E )-3,7-dimethyl-2-octen-1,8-diol, pheromone components of San Jose scaleinsect Quadraspidiotus pernicious and african monarch butterfly Danaus chrysippus

6-Methyl-6-hepten-2-one (3) on reaction with ethyl α-dimethylphosphonate/NaH gives a mixture of (E)-and (Z)-conjugated esters. The major (E)-isomer, (E)-ethyl-3,7-dimethyl-2,7-octadienoate (4), on reduction with LiAlH₄ at room temperature furnishes (E)-3,7-dimethyl-2,7-octadien-l-ol (5) which on propionylation affords (E)-3,7-dimethyl-2,7-octadienyl propionate (1). Carbinol (5) is converted into its silyl ether (E)-2,6-dimethyl-8-t-butyldimethylsilyloxy-l,6-octadiene (6) witht-Bu(Me)₂SiCl in CH₂Cl₂, which on hydroboronation-oxidation with 9-BBN/NaOH-H₂O₂ followed by disilylalion with (n-Bu)₄N⁺ F⁻ at room temperature, gives (E)-3,7-dimethyl-2-octen-l,8-diol (2).     

Total Synthesis,Stereochemical Assignment,and Field‐Testing of the Sex Pheromone of the Strepsipteran Xenos peckii

The sex pheromone of the endoparasitoid insect Xenos peckii (Strepsiptera: Xenidae) was recently identified as (7E,11E)‐3,5,9,11‐tetramethyl‐7,11‐tridecadienal. Herein we report the asymmetric synthesis of three candidate stereostructures for this pheromone using a synthetic strategy that relies on an sp³–sp² Suzuki–Miyaura coupling to construct the correctly configured C7‐alkene function. Comparison of ¹H NMR spectra derived from the candidate stereostructures to that of the natural sex pheromone indicated a relative configuration of (3R*,5S*,9R*). Chiral gas chromatographic (GC) analyses of these compounds supported an assignment of (3R,5S,9R) for the natural product. Furthermore, in a 16‐replicate field experiment, traps baited with the synthetic (3R,5S,9R)‐enantiomer alone or in combination with the (3S,5R,9S)‐enantiomer captured 23 and 18 X. peckii males, respectively (mean±SE: 1.4±0.33 and 1.1±0.39), whereas traps baited with the synthetic (3S,5R,9S)‐enantiomer or a solvent control yielded no captures of males. These strong field trapping data, in combination with spectroscopic and chiral GC data, unambiguously demonstrate that (3R,5S,9R,7E,11E)‐3,5,9,11‐tetramethyl‐7,11‐tridecadienal is the X. peckii sex pheromone.     

Secoiridoid Glycosides from Swertia mileensis

From the MeOH extract of the aerial parts of Swertia mileensis, four new secoiridoid glycosides were isolated, 4′‐O‐[(E)‐caffeoyl]swertiamarin ( 1 ), 4′‐O‐[(Z)‐coumaroyl]swertiamarin ( 7 ), 6′‐O‐[(E)‐coumaroyl]swertiamarin ( 8 ), and 6′‐O‐[(Z)‐coumaroyl]swertiamarin ( 9 ), together with five known compounds. Their structures were elucidated by NMR spectroscopy and tandem mass spectrometry. Detailed HPLC/MS analyses and MS/MS fragmentation pathways are discussed for the identification of the swertiamarin‐derived (E)/(Z) isomers 6 / 7 and 8 / 9 .     

GCxGC/TOF MS technique-A new tool in identification of insect pheromones: Analysis of the persimmon bark borer sex pheromone gland

Conventional gas chromatography with electroantennographic detection (GC-EAD) and two-dimensional (GC × GC) gas chromatography using a time-of-flight mass spectrometric detector (TOFMS), were combined to analyse the female sex pheromone gland extract of the persimmon bark borer, Euzophera batangensis. GC-EAD analysis produced two EAD responses in GC areas where no compounds were detected by FID detection. GC × GC/TOFMS analysis of this area indicated the presence of several chemicals, including (Z9,E12)-tetradeca-9,12-dien-1-ol and (Z9)-tetradec-9-en-1-ol, pheromone components of closely related Euzophera species. Spectral characteristics, retention behaviour and the ability to elicit GC-EAD responses imply that both identified unsaturated alcohols are candidates for E. batangensis sex pheromone components. GC × GC/TOFMS facilitated the analysis of complex matrices on a subnanogram level and was shown to have great potential as a powerful tool in the analysis of insect pheromones.     

Total Synthesis,Proof of Absolute Configuration,and Biosynthetic Origin of Stylopsal,the First Isolated Sex Pheromone of Strepsiptera

The asymmetric total synthesis of the diastereomers of stylopsal establishes the absolute configuration of the first reported sex pheromone of the twisted‐wing parasite Stylops muelleri as (3R,5R,9R)‐trimethyldodecanal. The key steps for the diastereo‐ and enantiodivergent introduction of the methyl groups are two different types of asymmetric conjugate addition reactions of organocopper reagents to α,β‐unsaturated esters, whereas the dodecanal skeleton is assembled by Wittig reactions. The structure of the natural product was confirmed by chiral gas chromatography (GC) techniques, GC/MS and GC/electroantennography (EAD) as well as field tests. An investigation into the biosynthesis of the pheromone revealed that it is likely to be produced by decarboxylation of a 4,6,10‐trimethyltridecanoic acid derivative, which was found in substantial amounts in the fat body of the female, but not in the host bee Andrena vaga. This triple‐branched fatty acid precursor thus seems to be biosynthesized de novo through a polyketide pathway with two consecutive propionate‐propionate‐acetate assemblies to form the complete skeleton. The simplified, motionless and fully host‐dependent female exploits a remarkable strategy to maximize its reproductive success by employing a relatively complex and potent sex pheromone.     

Lewis Acid Catalyzed,Selective Cyclopropane‐Ring Opening in Ingol Diterpene Derivatives

Lewis acid mediated skeletal rearrangement of the ingol diterpenoids 1 and 4 via regio‐ and stereospecific cyclopropane‐ring opening afforded the four new compounds 2, 3, 5 , and 6 , named nivulianol A–D (Scheme 1). Their structures were established by means of IR, MS, and in‐depth NMR spectroscopic analyses. The rearranged congeners were tested for lipopolysaccharide (LPS)‐induced prostaglandin (PG) E₂ (cyclooxygenase‐2) inhibition. Thereby, nivulianol B (=(1S*,2E,4R*,5S*,7Z,9S*,11R,13S*,14S*)‐14‐acetoxy‐5‐methoxy‐3,9,13‐trimethyl‐6‐(1‐methylethenyl)‐10‐oxo‐15‐oxatricyclo[9.3.1.0^1,11]pentadeca‐2,7‐dien‐4‐yl (2Z)‐2‐methylbut‐2‐enoate; 3 ) was found to be significantly active, with an IC₅₀ value of 36.3 μg/ml.     

Synthesis of Enantiomerically Pure Pheromones of South-Pacific Brown Algae: Hormosirene and Dictyopterene A

Hormosirene ((?)- 1 ; (1R,2R)-1-((1E,3Z)-1,3-hexadienyl)-2-vinylcyclopropane) is the specific sex attractant of several brown algae of the Australian shelf, while dictyopterene A ((+)- 2 ; (1R, 2R)-1-((1E)-1-hexenyl)-2-vinylcyclopropane) is found as a minor constituent of the pheromone bouquets. The asymmetric synthesis of the two hydrocarbons is performed by resolution of the amides (?)- 5 and (+)- 5a obtained from (?)-(R)-2-phenylglycinol and racemic trans-vinylcyclopropanecarboxylic acid (rac- 4 ) on silica gel. Both diastereoisomers are obtained optically pure. They are converted by stereoselective Wittig olefination into the title compounds. Compound (?)- 1 is the active mating pheromone of the reproductive system of the seaweed Xiphophora chondrophylla as established by biological-activity assays.     

Clerodendrumol,A New Triterpenoid from Clerodendrum yaundense Gürke (Lamiaceae)

A new lupane‐type triterpene named clerodendrumol ( 1 ), i.e., (16α)‐lupa‐12,20(29)‐dien‐16‐ol, together with five known compounds, octacosa‐(5Z,9Z)‐dienoic acid ( 3 ), tetracosanoic acid ( 4 ), genkwanin ( 5 ), (12S)‐hydroxyoctadeca‐(9Z,13E,15E)‐trienoic acid ( 6 ), and (9S)‐hydroxyoctadeca‐(10E,12E)‐dienoic acid ( 7 ), were isolated from the twigs of Clerodendrum yaundense. O‐Acetylclerodendrumol ( 2 ), a derivative of 1 , was prepared by a standard acetylation procedure applied to compound 1 . The structure of the new compound was elucidated using spectroscopic analysis (NMR and MS) data, and chemical conversions (acetylation and deacetylation). The human breast cancer cell line (MDA‐MB‐231) was sensitive to all test samples, and clerodendrumol ( 1 ) as well as its derivative 2 had good activity (IC₅₀ values 7.5 and 13.2 μM ). Genkwanin ( 5 ) exhibited strong activity on HeLa cell line with IC₅₀ 7.8 μM .     

Z‐sinapinic acid: the change of the stereochemistry of cinnamic acids as rational synthesis of a new matrix for carbohydrate MALDI‐MS analysis

Successful application of matrix‐assisted laser desorption/ionization (MALDI) MS started with the introduction of efficient matrices such as cinnamic acid derivatives (i.e. 3,5‐dimethoxy‐4‐hydroxycinnamic acid, SA; α‐cyano‐4‐hydroxycinnamic acid). Since the empirical founding of these matrices, other commercial available cinnamic acids with different nature and location of substituents at benzene ring were attempted. Rational design and synthesis of new cinnamic acids have been recently described too. Because the presence of a rigid double bond in its molecule structure, cinnamic acids can exist as two different geometric isomers, the E‐form and Z‐form. Commercial available cinnamic acids currently used as matrices are the geometric isomers trans or E (E‐cinnamic and trans‐cinnamic acids). As a new rational design of MALDI matrices, Z‐cinnamic acids were synthesized, and their properties as matrices were studied. Their performance was compared with that of the corresponding E‐isomer and classical crystalline matrices (3,5‐dihydroxybenzoic acid; norharmane) in the analysis of neutral/sulfated carbohydrates. Herein, we demonstrate the outstanding performance for Z‐SA. Sulfated oligosaccharides were detected in negative ion mode, and the dissociation of sulfate groups was almost suppressed. Additionally, to better understand the quite different performance of each geometric isomer as matrix, the physical and morphological properties as well as the photochemical stability in solid state were studied. The influence of the E/Z photoisomerization of the matrix during MALDI was evaluated. Finally, molecular modeling (density functional theory study) of the optimized geometry and stereochemistry of E‐cinnamic and Z‐cinnamic acids revealed some factors governing the analyte–matrix interaction. Copyright © 2013 John Wiley & Sons, Ltd.     

Structure elucidation of new acacic acid‐type saponins from Albizia coriaria

Three new acacic acid derivatives, named coriariosides C, D, and E ( 1–3 ) were isolated from the roots of Albizia coriaria. Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR studies and mass spectrometry as 3‐O‐[β‐D ‐xylopyranosyl‐(1 → 2)‐β‐D ‐fucopyranosyl‐(1 → 6)‐2‐(acetamido)‐2‐deoxy‐β‐D ‐glucopyranosyl]‐21‐O‐{(2E,6S)‐6‐O‐{4‐O‐[(2E,6S)‐2,6‐dimethyl‐ 6‐O‐(β‐D ‐quinovopyranosyl)octa‐2,7‐dienoyl]‐4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D ‐quinovopyranosyl)octa‐2,7‐dienoyl]‐β‐D ‐quinovopyranosyl}‐2,6‐dimethylocta‐2,7‐dienoyl}acacic acid 28‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐β‐D ‐glucopyranosyl ester ( 1 ), 3‐O‐{β‐D ‐fucopyranosyl‐(1 → 6)‐[β‐D ‐glucopyranosyl‐(1 → 2)]‐β‐D ‐glucopyranosyl}‐21‐O‐{(2E,6S)‐6‐O‐{4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D ‐quinovopyranosyl)octa‐2,7‐dienoyl]‐4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D ‐quinovopyranosyl)octa‐2,7‐dienoyl]‐β‐D ‐quinovopyranosyl}‐2,6‐dimethylocta‐2,7‐dienoyl}acacic acid 28‐O‐α‐L ‐rhamno pyranosyl‐(1 → 2)‐β‐D ‐glucopyranosyl ester ( 2 ), and 3‐O‐[β‐D ‐fucopyranosyl‐(1 → 6)‐β‐D ‐glucopyranosyl]‐21‐O‐{(2E,6S)‐6‐O‐{4‐O‐[(2E,6S)‐2,6‐dimethyl‐6‐O‐(β‐D ‐quinovopyranosyl)octa‐2,7‐dienoyl)‐β‐D ‐quinovopyranosyl]octa‐2,7‐dienoyl}acacic acid 28‐O‐β‐D ‐glucopyranosyl ester ( 3 ). Copyright © 2010 John Wiley & Sons, Ltd.     

A New Method for the Preparation of Intermediates for 2,6‐Substituted Anthrapyridazones

A new method for the preparation of 2‐substituted 6‐chloro‐2,7‐dihydro‐3H‐dibenzo[de ,h ]cynnoline‐3,7‐diones has been developed. The compounds have been obtained in an original three‐step procedure comprising the oxidation of 1‐methyl‐9,10‐anthraquinones with periodate or permanganate/brominating reagent systems, cyclization to 6‐chloro‐2,7‐dihydro‐3H‐dibenzo[de ,h ]cynnoline‐3,7‐dione, and selective alkylation thereof. The selected processes were applied in the efficient scale‐up of specific 2,6‐substituted 2,7‐dihydro‐3H‐dibenz[de ,h ]cinnolin‐3,7‐dione derivatives, currently being investigated pre‐clinically as anticancer agents.     

Synthesis of 4<Emphasis Type="Italic">E</Emphasis>,7<Emphasis Type="Italic">Z</Emphasis>-tridecadien-1-ylacetate,a component of the <Emphasis Type="Italic">Phthorimaea opercucella</Emphasis> sex pheromone

A new synthetic approach to 4E,7Z-tridecadien-1-ylacetate, a component of the Phthorimaea opercucella (Zeller) potato moth sex pheromone, was developed using a highly stereoselective Claisen rearrangement and Wittig reaction. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 235–236, May–June, 2007.     

A new sesquiterpenoid produced by female Callosobruchus rhodesianus (Pic): a possible component of the sex attractant pheromone

(E)-6-Ethyl-2,10-dimethyl-5,9-undecadienal was identified from female seed beetle, Callosobruchus rhodesianus (Pic), as an electroantennographic-detection (EAD) active compound in the male. The ratio of the (E)-6-ethyl-2,10-dimethyl-5,9-undecadienal and (3S,6E)-2,3-dihydrohomofarnesal, previously identified as a sex attractant pheromone, was estimated at approximately 1:4.5. In combination with the stereoisomer-activity relationship of 2,3-dihydrohomofarnesal, we suggest that this new compound might function as a minor sex attractant pheromone in C. rhodesianus.     

Annulenoide Tetrathiafulvalene:, 5,16‐Bis(1,3‐benzodithiol‐2‐yliden)‐5,16‐dihydrotetraepoxy‐ und 5,16‐Bis(1,3‐benzodithiol‐2‐yliden)‐5,16‐dihydrotetraepithio[22]annulene(2.1.2.1)

Annulenoid Tetrathiafulvalenes: 5,16‐Bis(1,3‐benzodithiol‐2‐ylidene)‐5,16‐dihydrotetraepoxy‐ and 5,16‐Bis(1,3‐benzodithiol‐2‐ylidene)‐5,16‐dihydrotetraepithio[22]annulenes(2.1.2.1) The title compounds are among the first tetrathiafulvalenes with annulene spacers, here with tetraepoxy‐[22]annulene(2.1.2.1) (see 3a ), tetraepithio[22]annulene(2.1.2.1) (see 3b ), and diepithiodiepoxy[22]annulene(2.1.2.1) (see 23 ) units. The annulenoid tetrathiafulvalenes 3a and 3b are prepared by cyclizing McMurry coupling of the 5,5′‐(1,3‐benzodithiol‐2‐ylidenemethylene)bis[furan‐ or thiophene‐2‐carbaldehydes] ( 8a or 8b , resp.) or by Wittig reaction of (1,3‐benzodithiol‐2‐yl)tributylphosphonium tetrafluoroborate ( 13b ) with tetraepoxy[22]annulene(2.1.2.1)‐1,12‐dione 20 (formation of 3a ) or diepithiodiepoxy[22]annulene(2.1.2.1)‐1,12‐dione 22 (formation of 23 ). The annulenoide tetrathiafulvalene 3a is obtained as a mixture of the isomers (E,E)‐ and (Z,Z)‐ 3a . At 130°, (Z,Z)‐ 3a rearranges quantitatively into the (E,E)‐isomer. Isomer (E,E)‐ 3a is a dynamic molecule, where the (E)‐ethene‐1,2‐diyl bridges rotate around the adjacent σ‐bonds. The tetraepithioannulene derivative 3b as well as 23 only exist in the (Z,Z)‐configuration. The oxidation of (E,E/Z,Z)‐ 3a with Br₂ yields the annulene‐bridged tetrathiafulvalene dication (E,E)‐ 3a _Ox, while with 4,5‐dichloro‐3,6‐dioxocyclohexa‐1,4‐diene‐1,2‐dicarbonitrile (DDQ) obviously only the radical cation 3a _Sem is formed, which belongs to the class of cyanine‐like violenes. The annulenoide tetrathiafulvalenes 3b and 23 , which exist only in the (Z,Z)‐configuration, obviously for steric reasons, cannot be oxidized by DDQ. Electrochemical studies are in agreement with these results.     

Quinolone Analogs 13: Synthesis of Novel 1,1′‐(2‐Methylenepropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) and Related Compounds

The reaction of the 4‐hydroxyquinoline‐3‐carboxylate 6 with pentaerythritol tribromide gave the 1,1′‐(2‐methylenepropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 11 , whose reaction with bromine afforded the 1,1′‐(2‐bromo‐2‐bromomethylpropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 12 . Compound 12 was transformed into the (Z)‐1,1′‐(2‐acetoxymethylpropene‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 13 or (E)‐1,1′‐[2‐(imidazol‐1‐ylmethyl)propene‐1,3‐diyl]di(4‐quinolone‐3‐carboxylate) 14 . Hydrolysis of the dimer (Z)‐ 13 or (E)‐ 14 with potassium hydroxide provided the (E)‐1,1′‐(2‐hydroxymethylpropene‐1,3‐diyl)di(4‐quinolone‐3‐carboxylic acid) 15 or (Z)‐1,1′‐[2‐(imidazol‐1‐ylmethyl)propene‐1,3‐diyl]di(4‐quinolone‐3‐carboxylic acid) 16 , respectively. The nuclear Overhauser effect (NOE) spectral data supported that those hydrolysis resulted in the geometrical conversion of (Z)‐ 13 into (E)‐ 15 or (E)‐ 14 into (Z)‐ 16 .     

Analysis of the Volatile Components in the Leaves of Cinna-momum camphora by Static Headspace Gas Chromatography Mass Spectrometry Combined with Accurate Weight Measurement

The volatile components in the leaves of C. camphora were analyzed by static headspace‐gas chromatography/mass spectrometry (HS‐GC‐MS) combined with accurate weight measurement. Accurate weight measurement obtained by Time‐of‐Flight mass spectrometry (TOF‐MS) helped to confirm the identification of volatiles in the analysis. 59 volatile components in the leaves of C. camphora were identified, which mainly included cis‐3‐hexen‐1‐ol (5.6%), 3‐hexen‐1‐ol, acetate (Z) (11.1%), β‐caryophyllene (15.4%), bicyclogermarene (8.4%), trans‐nerolidol (19.5%) and 9‐oxofarnesol (7.7%). The results show that method using HS‐GC‐MS combined with accurate weight measurement achieves reliable identification and has extensive application in the analysis of volatile components present in complex samples.     

Insect pheromone components: Use of 13C NMR spectroscopy for assigning the configuration of CC double bonds of monoenic or dienic pheromone components and for quantitative determination of Z/E mixtures

Several insect sex pheromone components and structural analogues have been characterized by ¹³C NMR spectroscopy. The evaluation of the difference between the chemical shift values of the allytic carbons present in the diunsaturated pheromone components and those of the carbons having the same position on the n-alkane chain of the corresponding saturaated compounds was used to assign the configuration of the CC double bonds present into such dienic compounds. The technique avoids the need to use the nuclear Overhausser effect; it allows quantitative evaluation, with good accuracy, of the stereoisomeric composition of mixtures of synthetic monoenic or dienic pheromone components such as (Z)- and (E)-9-tetraceden-1-yl acetate and (Z)- and (E)-9,11-dodecadien-1-yl acetate.     

Sequence and phosphorylation level determination of two donkey β‐caseins by mass spectrometry

Two coeluting components, with experimentally measured M_r values of 25529 and 24606 Da, were identified by reversed‐phase high‐performance liquid chromatography (RP‐HPLC) and mass spectrometric analysis in the dephosphorylated casein fraction of a milk sample collected from an individual donkey belonging to the Ragusano breed of the east of Sicily. By coupling enzymatic digestions, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) and RP‐HPLC/nano‐electrospray ionization tandem mass spectrometry (nESI‐MS/MS) analysis, the two proteins were identified as donkey β‐CNs and their sequences characterized completely, using the two known β‐CNs from mare as references. The two donkey β‐CNs, showing a mass difference of 923 Da, differ by the presence of the domain E²⁷SITHINK³⁴ in the full‐length component (M_r 25529 Da). In comparison with the mare's β‐CNs used as reference, they present nine amino acid substitutions: L→S³⁷, R→H⁵², S→N⁸¹, P→V⁸⁴, L→V⁹¹, R→Q²⁰³, P→L/I²⁰⁶, L→F²¹⁰ and A→P²¹⁹. Together, these substitutions account for the increase of 18 Da in the M_r of the donkey β‐CNs with respect to the counterparts from the mare. The molecular mass determination by ESI‐MS for the phosphorylated proteins showed that the full‐length component was composed of highly multi‐phosphorylated isoforms with five to seven phosphate groups. By analogy with the homologous mare's β‐CNs, the full‐length (226 amino acids) β‐CN was termed variant A, whereas the shorter (218 amino acids) β‐CN was termed variant A^Δ5. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis of 5<Emphasis Type="Italic">Z</Emphasis>,9<Emphasis Type="Italic">E</Emphasis>-tridecadien-1-ylacetate,an attractant of <Emphasis Type="Italic">Trichoplusia ni</Emphasis>

A new synthetic scheme for 5Z,9E-tridecadien-1-ylacetate, an attractant of the cabbage looper Trichoplusia ni (Huebner) was developed using a highly stereoselective Claisen rearrangement.