Sequential substitution of 1,2-dichloro-ethene: a convenient stereoselective route to (9Z,11E)-, (10E,12Z)- and (10Z,12Z)-

Conjugated linoleic acid (CLA) isomers are present in human foods derived from milk or ruminant meat. To study their metabolism, (9Z,11E)-, (10E,12Z)- and (10Z,12Z)-[1-(14)C]-octadecadienoic acids with high radiochemical and isomeric purities (>98%) were prepared by stereoselective multi-step syntheses involving sequential substitution of 1,2-dichloro-ethene. In the case of the (9Z,11E) isomer, a first metal-catalyzed cross-coupling reaction between (E)-1,2-dichloro-ethene and 2-non-8-ynyloxy-tetrahydro-pyran, obtained from 7-bromo-heptan-1-ol, gave a conjugated chloroenyne. A second coupling reaction with hexylmagnesium bromide provided a heptadecenynyl derivative. Stereoselective reduction of the triple bond and bromination afforded (7E,9Z)-17-bromo-heptadeca-7,9-diene. Formation of the Grignard reagent and carbonation with 14CO(2) gave (9Z,11E)-[1-(14)C]-octadeca-9,11-dienoic acid (overall yield from 7-bromo-heptan-1-ol, 14.4%). (10E,12Z)- and (10Z,12Z)-[1-(14)C]-octadeca-10,12-dienoic acids were synthesized by the same methodology using 1-heptyne, 8-bromo-octan-1-ol and, respectively, (E)-1,2-dichloro-ethene and its (Z) isomer (overall yield from 8-bromo-octan-1-ol, 13.1% (10E,12Z); 17.2% (10Z,12Z)). Impurities (<2% if present) were identified as being (E,E) CLA isomers and were removed by RP-HPLC. Metabolism studies in animal are in progress.     

Synthesis of (S)-13-Hydroxy (2E,4E,8E)- and (2E,4E,8Z)-Tetradecatrienoic Acids

The syntheses of (S)-13-hydroxy-(2E,4E,8E)-tetradecatrienoic acid (1) and (2E,4E,8Z)-tetradecatrienoic acid (2) were carried out by using the Wittig reaction as the key step. The asymmetric center at C-13 and the double bond between C-8 and C-9 for natural compound 1 were reconfirmed as being of (S) configuration and E, respectively.

The relationship between the structure of the unsaturated hydroxy fatty acids and their inhibitory effect on the growth of lettuce was investigated.     

Responses of male winter moths (Operophtera brumata) to their sex attactant (3Z,6Z,9Z)-1,3,6,9 nonadecatetraene and to some structural analogues

Conclusion (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene, the synthetic sex pheromone of the female of O. brumata is highly active in attracting males of this species in the field (Germany and Switzerland). No analogous compounds possessing attractivity to O. brumata males have been found up to now, nor did they show any inhibitory effects to the same species.Therefore (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene (I) can be recommended as a good attractant in the prognosis or monitoring of this lepidopteran pest.     

Synthesis of (6Z,9Z,11E)-octadecatrienoic and (8Z,11Z,13E)-eicosatrienoic acids and their [1-(14)C]-radiolabeled analogs

In order to study the metabolic pathway and the physiological effects of 9c,11t-18:2 (major isomer of conjugated linoleic acid) and its C(18:3) and C(20:3) metabolites, 6c,9c,11t-18:3 and 8c,11c,13t-20:3 and their [1-(14)C]-radiolabeled analogs were prepared stereoselectively by total synthesis. The 8c,11c,13t-20:3 was obtained in 11 steps. The synthesis involves a highly stereoselective Wittig reaction between 3-(t-butyldiphenylsilyloxy)propanal and the ylide of 7-(2-tetrahydropyranyloxy)heptanylphosphonium salt which gave (3Z)-1-(t-butyldiphenylsilyloxy)-10-(2-tetrahydropyranyloxy)dec-3-ene in a first step. Then the t-butyldiphenylsilyl derivative was deprotected selectively and the resulting alcohol function was converted via a bromide into a phosphonium salt. The second stereoselective Wittig condensation between the phosphonium salt and commercial (2E)-non-2-enal under cis-olefinic conditions using Lithium hexamethyldisilazide as base afforded the (7Z,10Z,12E)-1-(2-tetrahydropyranyloxy)nonadeca-7,10,12-triene in a very good isomeric purity. The intermediate product was brominated and transformed by reaction with magnesium into Grignard reagent, which was one-carbon elongated by unlabeled or labeled carbon dioxide to obtain the 8c,11c,13t-20:3 in good isomeric purity (95%) and high radiochemical purity for its [1-(14)C]-radiolabeled analog (99%). 6c,9c,11t-18:3 was synthesized in a similar way by using 5-(2-tetrahydropyranyloxy)pentanylphosphonium salt in place of 7-(2-tetrahydropyranyloxy)heptanylphosphonium salt in a first step. Other reactions were unchanged and products were obtained in similar yields. Similar to 8c,11c,13t-20:3, the 6c,9c,11t-18:3 was obtained in a very good isomeric purity (95%) and its [1-(14)C]-radiolabeled analog in a high radiochemical purity (95%).     

Electroantennogram responses of the European corn borer,Ostrinia nubilalis,to (Z)- and (E)-11-tetradecenyl acetates

Antennal responses of male European corn borer moths, Ostrinia nubilalis, to their two pheromone components, (Z)- and (E)-11-tetradecenyl acetates (tda), were studied. The electroantennogram (EAG) response was highest when the ventral side and lowest when the dorsal side of the antenna faced the air stream carrying the chemical stimulus. Repetitive stimulation with one of the isomers resulted in adaptation which affected the amplitude of response in subsequent tests of both (Z)- and (E)-11-tda. This suggested that the receptors for the two tda isomers are either identical or highly interactive. Mixtures of the two pheromone components did not elicit higher responses than the major component, (Z)-11-tda. A significant difference was observed between London and New York strains of this insect in their relative responses to (Z)- and (E)-11-tda. EAG responses of hybrids of these two strains resembled those for the New York strain.     

Effect of (E4, Z6)-4,6-Hexadecadienal in attraction of Stathmopoda masinissa with its pheromone components of Korean population

Timely insecticidal application for Stathmopoda masinissa Meyrick (Lepidoptera: Stathmopodidae), is important, for reducing damage to persimmon (Diospyros kaki Thunb.), an important tree fruit cultivated in Korea. In this regard, the early and precise detection of adult S. masinissa is desirable. In this study, we report the effect of (E4,Z6)-4,6-hexadecadienal (E4,Z6-16Ald) with sex pheromone components in attracting S. masinissa males. The sex pheromone of S. masinissa in the Korean population comprised two components, (E4,Z6)-4,6-hexadecadienyl acetate (E4,Z6-16Ac) and (E4,Z6)-4,6-hexadecadienol (E4,Z6-16OH). It was shown that the E4,Z6-16Ald acts as a synergist of E4,Z6-16Ac for attracting S. masinissa in the Japanese population. To test whether E4,Z6-16Ald could be used as an attractant in the Korean population, the E4,Z6-16Ald with the two pheromone components was evaluated in attracting S. masinissa males. Electroantennography (EAG) assays were performed to determine the antennal responses of S. masinissa males to the two pheromone components and E4,Z6-16Ald tested. A field attraction test with a combination of pheromones and E4,Z6-16Ald was carried out for 3 years in three different regions in Korea. E4,Z6-16Ald elicited as high a response as the two pheromone components. A mixture of the two pheromone components and E4,Z6-16Ald and a mixture of E4,Z6-16Ac and E4,Z6-16Ald attracted more S. masinissa males than a mixture of E4,Z6-16Ac and E4,Z6-16OH, the pheromone of Korean population. This new pheromone lure formulation with E4,Z6-16Ald is expected to contribute to the precise detection of S. masinissa by luring males to pheromone-baited traps.     

Stereochemical analysis of prenyltransferase reactions leading to (Z)- and (E)-polyprenyl chains

A feasible method was developed to determine the stereochemical direction of the C-C bond formation with respect to the face of the double bond of isopentenyl diphosphate in the prenyltransferase reactions. This method was applied to the reactions of undecaprenyl diphosphate synthase and heptaprenyl diphosphate synthase, which catalyze (Z)-prenyl chain elongation and (E)-prenyl chain elongation, respectively. In both cases, the C-C bond formation was found to take place at the si face of the double bond with elimination of one of the hydrogens of C-2 in a syn fashion.     

Large-scale preparation of (9Z,12E)-[1-(13)C]-octadeca-9,12-dienoic acid, (9Z,12Z,15E)-[1-(13)C]-octadeca-9,12,15-trienoic acid and their [1-(13)C] all-cis isomers

Several grams of labelled trans linoleic and linolenic acids with high chemical and isomeric purities (>97%) have been prepared for human metabolism studies. A total of 12.5 g of (9Z, 12E)-[1-(13)C]-octadeca-9,12-dienoic acid and 6.3 g of (9Z,12Z, 15E)-[1-(13)C]-octadeca-9,12,15-trienoic acid were obtained in, respectively, seven steps (7.8% overall yield) and 11 steps (7% overall yield) from 7-bromo-heptan-1-ol. The trans bromo precursors used for the labelling were synthesised by using copper-catalysed couplings. The trans fatty acids were then obtained via the nitrile derivatives. A total of 23.5 g of (9Z,12Z)-[1-(13)C]-octadeca-9, 12-dienoic acid and 10.4 g of (9Z,12Z,15Z)-[1-(13)C]-octadeca-9,12, 15-trienoic acid were prepared in five steps in, respectively, 32 and 18% overall yield. Large quantities of bromo and chloro precursors were synthesised from the commercially available acid according to Barton's procedure. In all cases, the main impurities (>0.5%) of each labelled fatty acid have been characterised.     

10,20-Methanorhodopsins: (7E,9E,13E)-10,20-methanorhodopsin and (7E,9Z,13Z)-10,20-methanorhodopsin. 11-cis-locked rhodopsin analog pigments with unusual thermal and photo-stability

Synthesis of the retinal analog, 10,20-methanoretinal (R6), where the 11Z conformation is locked in a six-membered ring, yielded four stereoisomers (7E,9E,13E, 7E,9E,13Z, 7E,9Z,13E and 7E,9Z,13Z). These four isomers were separated by straight-phase isocratic HPLC and identified by 1H-NMR and NOE analysis. All isomers smoothly recombined with bovine opsin at a relatively high rate (5-10% of that of the natural chromophore 11Z-retinal). The corresponding 13E and 13Z isomers yielded identical analog pigments, probably due to rapid thermal isomerization around the C13 = C14 double bond. The (7E,9E)-isomers produced a pigment with maximal absorbance at 510 nm, while the pigment produced from the (7E,9Z)-isomers had maximal absorbance at 494 nm. Based upon kinetic considerations, the chromophore structure in the 510-nm-absorbing pigment should be (7E,9E,13E), i.e. equivalent to 11Z-retinal and rhodopsin, while the chromophore structure in the 494-nm-absorbing pigment should be (7E,9Z,13Z), i.e. equivalent to (9Z,11Z,13Z)-rhodopsin, an isorhodopsin analog. In analogy to the 11-cis-locked rhodopsin analogs Rh5 and Rh7, the 510-nm-absorbing pigment, (7E,9E,13E)-10,20-methanorhodopsin, was dubbed Rh6 and the 494-nm-absorbing pigment. (7E,9Z,13Z)-10,20-methanorhodopsin, was dubbed Iso6. The opsin shift of Rh6 (2660 cm-1) is practically identical to that of rhodopsin itself (2650 cm-1). Rh6 and Iso6 are nearly as stable as rhodopsin towards hydroxylamine and solubilization in detergent solution and could be easily purified and reconstituted into proteoliposomes by established procedures. Due to the 11-cis-lock, Rh6 is much less photolabile (bleaching rate less than 1%) than rhodopsin, but it is not completely photostable, probably since photoisomerization around the C7 = C8, C9 = C10 and C13 = C14 bonds is allowed. Illumination of either Rh6 or Iso6 does not generate the common photointermediates but instead produces a complex pattern of photochemical transitions, which during continuous illumination leads to the same final steady state, absorbing at 498 nm. This process is accompanied by a slow but steady loss of pigment, probably due to hydrolytic release of chromophore, which is markedly accelerated in the presence of hydroxylamine. In a physiological assay (light-dependent activation of rod cGMP phosphodiesterase) Rh6 is only marginally active and this probably reflects conformational changes accompanying the above-mentioned photochemical transitions. This supports the concept that normal rhodopsin-based phototransduction requires 11Z to all-E isomerization.(ABSTRACT TRUNCATED AT 400 WORDS)     

Synthesis and sulfatase inhibitory activities of (E)- and (Z)-4-hydroxytamoxifen sulfamates

We report the development of (E)- and (Z)-4-hydroxytamoxifen sulfamates as estrone sulfatase inhibitors, potential therapeutic agents for the treatment of breast cancer. Both compounds competitively inhibit estrone sulfatase isolated from rat liver with apparent Ki of 35.9 microM for (E)-4-hydroxytamoxifen sulfamate and an apparent Ki of > 500 microM for the (Z) isomer.     

Synthesis and biological activity of (24E)- and (24Z)-26-hydroxydesmosterol

Using 3β-hydroxychol-5-en-24-oic acid (4) as starting material, the diastereoisomeric allylic alcohols (24E)-26-hydroxydesmosterol (2) and (24Z)-26-hydroxydesmosterol (3) have been synthesised in six steps with 67% and 12% overall yield, respectively. Both of these isomers are found in newborn mouse brain where sterol synthesis is high. Unlike desmosterol (1), neither of these isomers is a ligand to the liver x receptors and thus represents a novel biological deactivation mechanism avoiding cholesterol synthesis.     

Stereoselective synthesis of (6Z,10E,12Z)-octadeca-6,10,12-trienoic acid, (8Z,12E,14Z)-eicosa-8,12,14-trienoic acid,and their [1-14C]-radiolabeled analogs

To study the metabolic fate of conjugated linoleic acid isomers, we synthesized, in seven steps, from 1-heptyne, (6Z,10E,12Z)-octadeca-6,10,12-trienoic acid, (8Z,12E,14Z)-eicosa-8,12,14-trienoic acid, and their [1-(14)C]-analogs. In the case of (6Z,10E,12Z)-octadecatrienoic acid, a series of palladium-catalyzed cross-coupling reactions between 1-heptyne and (E)-1,2-dichloro-ethene, a coupling reaction with a Grignard reagent and cleavage of the dioxolane gave (E)-dodec-4-en-6-ynal 3. Stereoselective Wittig reaction between aldehyde 3 and triphenyl-[5-(tetrahydro-pyran-2-yloxy)-pentyl]-phosphonium provided a dienyne. Stereocontrolled reduction of the triple bond and replacement of the tetrahydropyranyl group by a bromine gave (5Z,9E,11Z)-1-bromo-heptadeca-5,9,11-triene 10. Formation of the alkenyl lithium derivative and carbonation with CO(2) furnished (6Z,10E,12Z)-octadecatrienoic acid. (8Z,12E,14Z)-eicosa-8,12,14-trienoic acid was obtained by the same route but using triphenyl-[5-(tetrahydro-pyran-2-yloxy)-heptyl]-phosphonium iodide for the Wittig reaction. [1-(14)C]-analogs were obtained from the bromides by carbonation with (14)CO2. In all cases, chemical or radiochemical purities were found to be better than 95% after purification by flash chromatography on silica gel (>99% after additional purification by RP-HPLC). Metabolism studies in animals are in progress.     

(E)- and (Z)-1,2,4-triazolylchromanone oxime ethers as conformationally constrained antifungals

A series of 1,2,4-triazolylchromanone oxime ethers were synthesized and tested for in vitro antifungal activity. Many of these derivatives exhibit high activity against Candida albicans, Saccharomyces cerevisiae, Aspergillus niger and Microsporum gypseum.     

Stereospecificity of the (Z)-9 desaturase that converts (E)-11-tetradecenoic acid into (Z,E)-9,11-tetradecadienoic acid in the biosynthesis of Spodoptera littoralis sex pheromone

Moth pheromone glands contain desaturases that catalyze the formation of conjugated dienoic fatty acids. In this article we present the first stereochemical study on one of these enzymes, namely the Delta(9) desaturase of (E)-11-tetradecenoic acid, using the moth Spodoptera littoralis as a biological model and enantiopure deuterated probes derived from tridecanoic acid. Gas chromatography coupled to mass spectrometry analysis of methanolyzed lipidic extracts from glands incubated with each individual probe showed that in the transformation of (E)-11-tetradecenoic acid into (Z,E)-9,11-tetradecadienoic acid both pro-(R) hydrogen atoms at C9 and C10 are removed from the substrate.     

A Convenient Synthesis of a Mixture of (Z,Z)-3,13-Octadecadienyl Acetate and Its (E,Z)-Isomer,the Attractant for the Cherrytree Borer

A 1:1 mixture of (Z, Z)-3,13-octadecadien-1-ol and its (E, Z)-isomer was synthesized by a Wittig reaction whose stereoselectivity was adjusted to give the products in the required ratio. The corresponding acetate mixture is useful as the attractant for Synanthedon hector.     

Concise synthesis of (8Z,11Z,14Z)-8,11,14-heptadecatrienal, (7Z,10Z,13Z)-7,10,13-hexadecatrienal, and (8Z,11Z)-8,11-heptadecadienal, components of the essential oil of marine green alga Ulva pertusa

The long-chain aldehydes, (8Z,11Z,14Z)-8,11,14-heptadecatrienal, (7Z,10Z,13Z)-7,10,13-hexadecatrienal, and (8Z,11Z)-8,11-heptadecadienal, were concisely synthesized by using Grignard coupling, catalytic hydrogenation with the Lindlar catalyst, and oxidation with Dess-Martin periodinane as the key steps. Particularly, (8Z,11Z,14Z)-8,11,14-heptadecatrienal and (7Z,10Z,13Z)-7,10,13-hexadecatrienal both possessed a seaweed-like odor.     

Concise Synthesis of (8Z,11Z,14Z)-8,11,14-Heptadecatrienal, (7Z,10Z,13Z)-7,10,13-Hexadecatrienal,and (8Z,11Z)-8,11-Heptadecadienal,Components of the Essential Oil of Marine Green Alga Ulva pertusa

The long-chain aldehydes, (8Z,11Z,14Z)-8,11,14-heptadecatrienal, (7Z,10Z,13Z)-7,10,13-hexadecatrienal, and (8Z,11Z)-8,11-heptadecadienal, were concisely synthesized by using Grignard coupling, catalytic hydrogenation with the Lindlar catalyst, and oxidation with Dess–Martin periodinane as the key steps. Particularly, (8Z,11Z,14Z)-8,11,14-heptadecatrienal and (7Z,10Z,13Z)-7,10,13-hexadecatrienal both possessed a seaweed-like odor.     

Facile syntheses for (5Z,9Z)-5,9-hexadecadienoic acid, (5Z,9Z)-5,9-nonadecadienoic acid, and (5Z,9Z)-5,9-eicosadienoic acid through a common synthetic route

The delta 5,9 fatty acids (5Z,9Z)-5,9-hexadecadienoic acid, (5Z,9Z)-5,9-nonadecadienoic acid, and (5Z,9Z)-5,9-eicosadienoic acid were synthesized for the first time in four steps (9-12% overall yield) starting from commercially available 2-(2-bromoethyl)-1,3-dioxolane. The synthetic approach provided enough material to corroborate the structure and stereochemistry of (5Z,9Z)-5,9-nonadecadienoic acid which was recently identified in the flowers of Malvaviscus arboreus (Malvaceae). The novel phospholipids 1-hexadecanoyl-2-[(5Z,9Z)-5,9-eicosadienoyl]-sn-glycer o-3-phosphocholine and 1-octadecanoyl-2-[(5Z,9Z)-5,9-eicosadienoyl]-sn- glycero-3-phosphocholine were also synthesized from commercially available L-alpha-phosphatidylcholine (egg yolk) and characterized by positive ion electrospray mass spectrometry. These are the first examples of unsymmetrical phospholipids with saturated fatty acids at the sn-1 position and delta 5,9 fatty acids at the sn-2 position.     

Estrogenic/antiestrogenic and scavenging properties of (E)- and (Z)-resveratrol

Resveratrol, natural compound found in grapes and wine, has been reported to have a variety of health benefit properties. Based on the structural similarity to the synthetic estrogen diethylstilbestrol, we investigated estrogenic/antiestrogenic effects on human breast cancer cell lines, MCF-7 and MVLN, and scavenging properties using DPPH of both (E)- and (Z)-isomers. Both isomers increased the in vitro growth of MCF-7 cell lines at medium concentrations (10 and 25 microM) whereas the low concentrations (0.1 and 1 microM) had no effect and the high concentration (50 microM) decreased the cell growth and was cytotoxic. The 25 microM (E)-isomer alone was able to reduced the proliferation induced by the estradiol. Low concentrations of (E)- and (Z)-resveratrol (0.1 and 1 microM) and medium concentration 10 microM (Z)-resveratrol did not interfere with the estrogen receptor. In contrast, medium concentrations of (E)-resveratrol (10 and 25 microM) and (Z)-resveratrol (25 microM) functioned as superagonists of estradiol. Whatever the model used, MCF-7 or MVLN cell lines, (Z)-resveratrol was less effective than (E)-resveratrol. Extinction of DPPH and Fe(III) reduction experiments showed that both isomers of resveratrol could act as free radicals scavengers or pro-oxidant compounds. The properties of low concentrations of resveratrol raise the possibility that structure-function studies could lead to the development of more selective estrogen receptor agonists and antagonists, which could be useful as a therapeutic agent.