Ionylideneacetic Acids and Abscisic Acid Biosynthesis by Cercospora rosicola

Several compounds having the basic α-ionylideneacetic acid structure were tested in Cercospora rosicola resuspensions. At 100 μm, all the compounds inhibited abscisic acid (ABA) biosynthesis. Time studies with unlabelled and deuterated (2Z,4E)- and (2E,4E)-α-ionylideneacetic acids showed rapid conversions into both (2Z,4E)- and (2E,4E)-4′-keto-α-ionylideneacetic acids as major products. Incorporation of the label into ABA was specific for the 2Z,4E-isomer. Minor products, identified by GC-MS, were (2Z,4E)- and (2E,4E)-4′-hydroxy-α-ionylideneacetic acids and (2Z,4E)-1′-hydroxy-α-ionylideneacetic acid. The conversion to (2Z,4E)-l′-hydroxy-α-ionylideneacetic acid has not been previously reported and was specific for the 2Z,4E-isomer. A time study for the conversion of methyl esters of [²H₃]-(2Z,4E)- and [²H₃]-(2E,4E)-4′-keto-α-ionylideneacetates showed a slow introduction of the l′-hydroxyl group and specificity for 2Z,4E-isomer. Conversion of the ethyl esters of (2Z,4E)- and (2E,4E)-l′-hydroxy-α-ionylideneacetates into the ethyl esters of both ABA and (2E,4E)-ABA demonstrated that ABA can be formed by oxidation of the 4′-position after the insertion of the 1′-hydroxy group. The ethyl 1′-hydroxy acids were also isomerized to the corresponding ethyl (2Z,4E)- and ethyl (2E,4E)-3′-hydroxy-β-ionylideneacetates. Ethyl (2Z,4E)-1′-hydroxy acid also gave small amounts of ethyl l′,4′-trans-diol of ABA. These results suggest that ABA may be formed through a (2Z,4E)-1′-hydroxy-α-ionylidene-type intermediate in addition to the previously proposed route through (2Z,4E)-4′-keto-α-ionylideneacetic acid.     

The Influences of Jasmonic Acid Methyl Ester on Microtubules in Potato Cells and Formation of Potato Tubers

Amides in a CH₂Cl₂ extract from the fruits of Piper retrofractum were detected by HPLC/APCI-MS. Seven new unsaturated amides, together with six known ones, were isolated, and their structures were determined to be N-isobutyl-2E,4E,12Z-octadecatrienamide (1), N-isobutyl-2E,4E,14Z-eicosatrienamide (2), 1-(octadeca-2E,4E,12Z-trienoyl)piperidine (3), 1-(eicosa-2E,4E,14Z-trienoyl)piperidine (4), 1-(octadeca-2E,4E-dienoyl)piperidine (5), 1-(eicosa-2E,4E-dienoyl)piperidine (6), and 1-(eicosa-2E,14Z-dienoyl)piperidine (7) on the basis of chemical and spectroscopic evidence.     

Antennal response of codling moth males, Cydia pomonella L. (Lepidoptera: Tortricidae), to the geometric isomers of codlemone and codlemone acetate

Single sensillum recordings from Cydia pomonella male antennae showed three different types of receptor neurons. The most abundant type was most sensitive to the main pheromone compound (E,E)-8,10-dodecadienol, while its response to the geometric isomers E,Z, Z,E and Z,Z was comparable to a tenfold lower dose of (E,E)-8,10-dodecadienol. This neuron type also responded to the four behaviorally antagonistic isomers of (Δ,Δ)-8,10-dodecadienyl acetate, among which it was most sensitive to the E,E isomer. Cross-adaptation studies showed that these compounds were all detected by the same receptor neuron type. Receptor neurons specifically tuned to (E,Z) or (Z,Z)-8,10-dodecadienol were not found, although these two compounds are behaviorally active. A second type of receptor neuron responded to all isomers of (Δ,Δ)-8,10-dodecadienyl acetate and was most sensitive to the E,E isomer. This neuron type did not respond to any of the isomers of (Δ,Δ)-8,10-dodecadienol. A third receptor neuron type was highly sensitive to the plant compound α-farnesene. The finding that the receptor neuron type tuned to the main pheromone compound responded even to strong behavioral antagonists aids the interpretation of ongoing behavioral studies for the development of the mating disruption technique in codling moth. Accepted: 3 March 2000     

Regio- and enantio-selective acetylation of 3,3,3-trifluoro-2-arylpropane-1,2-diols using Candida antarctica lipase

Of nine commercially available lipases, lipase SP 435 from Candida antarctica, showed moderate enantioselectivity (E=17) for acetylation of racemic 3,3,3-trifluoro-2-phenylpropane-1,2-diol, 2, with vinyl acetate in diisopropyl ether (S selectivity). The other eight had low selectivities, with E values below 10. The selectivity and reactivity of SP 435 for 2 was markedly improved in dichloroethane (E=41). Moreover, SP 435 had moderate to high selectivity for the related compounds 3,3,3-trifluoro-2-(1-naphthyl)-propane-1,2-diol, 4, (E=20), 3,3,3-trifluoro-2-(indol-3-yl)propane-1,2-diol, 6, (E=80), and 3,3,3-trifluoro-2-(pyrrol-2-yl)-propane-1,2-diol, 8, (E=17).     

(10E,12Z,15Z)-9-Hydroxy-10,12,15-octadecatrienoic Acid Methyl Ester as an Anti-inflammatory Compound from Ehretia dicksonii

The methanol extract of Ehretia dicksonii provided (10E,12Z,15Z)-9-hydroxy-10,12,15-octadecatrienoic acid methyl ester (1) which was isolated as an anti-inflammatory compound. Compound 1 suppressed 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced inflammation on mouse ears at a dose of 500 μg (the inhibitory effect (IE) was 43%). Linolenic acid methyl ester did not inhibit this inflammation at the same dose. However, the related compounds of 1, (9Z,11E)-13-hydroxy-9,11-octadecadienoic acid (5) and (9Z,11E)- 13-oxo-9,11-octadecadienoic acid (6), showed potent activity (IE_{500 μg} of 63% and 79%, respectively). Compounds 1, 4 ((9Z,12Z,14E)-16-hydroxy-9,12,14-octadecatrienoic acid), 5 and 6 also showed inhibitory activity toward soybean lipoxygenase at a concentration of 10 μg/ml.     

Isobutyl Amides from Pepper (Piper nigrum L.)

Four isobutyl amides were isolated from the fruits of white pepper (Piper nigrum L.) and identified to be N-isobutyl-13-(3,4-methylenedioxyphenyl)-2E,4E,12E-tridecatrienamide (3, guineensine), N-isobutyl-2E,4E,8Z-eicosatrienamide (5), N-isobutyl-2E,4E-octadecadienamide (6) and N-isobutyl-2E,4E-decadienamide (7, pellitorine).     

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.     

Farnesyl and α-Ionylideneethyl Tertiary and Quaternary Amines: Their Influence on Abscisic Acid Biosynthesis by Cercospora rosicola

Farnesyl and α-ionylideneethyl compounds with tertiary and quaternary amine functional groups were synthesized and their effects on abscisic acid (ABA) biosynthesis of Cercospora rosicola observed. The trimethylammonium compounds were lethal at 10 μm and inhibitory at 10 μm, but lesser amounts of α-ionylideneethyltrimethylammonium iodide enhanced ABA biosynthesis. N,N-Dimethylfarnesylamine had little effect on ABA biosynthesis. N,N-Dimethyl (2Z,4E)- and (2E,4E)-α-ionylideneethylamines inhibited ABA biosynthesis at 100 μm but had no or little effect at lower concentrations. Farnesol and farnesylpyrophosphate (FPP) enhanced ABA biosynthesis. FPP appears to be both a precursor and an inducer and farnesol is an inducer of ABA biosynthesis. N,N-Dimethyl (2Z,4E)- and (2E,4E)-α-ionylideneethylamines were converted to N,N-dimethyl (2Z,4E)- and (2E,4E)-4′-keto-α-ionylideneethylamines, respectively. These conversions are analogous to those reported for α-ionone and α-ionylideneacetic acids and show that basic as well as acidic and neutral compounds with α-ionone type rings can undergo oxidation at the 4′-position. α-Ionylideneacetic acids inhibited growth of C. rosicola and the dimethylamines enhanced growth. Complete feedback inhibition was obtained with 400 μm of ABA.     

A Novel Pathway for the Partial Oxidation of Propionyl-CoA to Pyruvate via Seven-carbon Tricarboxylic Acids in Yeasts

We examined the biosynthetic pathway of abscisic acid (ABA) after isopentenyl diphosphate in a fungus, Cercospora cruenta. All oxygen atoms at C-1, -1, -1′, and -4′ of ABA produced by this fungus were labeled with ¹⁸O from ¹⁸O₂. The fungus did not produce the 9Z-carotenoid possessing γ-ring that is likely a precursor for the carotenoid pathway, but produced new sesquiterpenoids, 2E,4E-γ-ionylideneethane and 2Z,4E-γ-ionylideneethane, along with 2E,4E,6E-allofarnesene. The fungus converted these sesquiterpenoids labeled with ¹³C to ABA, and the incorporation ratio of 2Z,4E-γ-ionylideneethane was higher than that of 2E,4E-γ-ionylideneethane. From these results, we concluded that C. cruenta biosynthesized ABA by the direct pathway via oxidation of ionylideneethane with molecular oxygen following cyclization of allofarnesene. This direct pathway via ionylideneethane in the fungus is consistent with that in Botrytis cinerea, except for the positions of double bonds in the rings of biosynthetic intermediates, suggesting that the pathway is common among ABA-producing fungi.     

Leaf Alcohol

The diethylamine-catalyzed aldol condensation of E-2-hexenal yielded a mixture of 2-E,4-E,6-E- (IV-a) and 2-E,4-Z,6-E-4-ethyldeca-2,4,6-triene-1-al (IV-b). Structual and geometrical elucidation of both alcohols were made by means of spectral evidence as well as by the catalytic hydrogenation leading to the same 4-ethyldecanol (VI). The “b-peak substance” detected in the leaf alcohol reaction products was proved to be identical with 4-ethyldecanol (VI). The treatment of the trienal containing the central Z-double bond with sodium under the leaf alcohol reaction condition failed to afford ethyl-propyl-benzyl alcohol, but gave 4-ethyldecanol (VI). This result safely excludes the operation of the previously suspected valence tautomerism (Cope rearrangement) in the leaf alcohol reaction, and accounts for the pathway of the formation of (VI).     

Synthesis and Biological Activities of Novel (Z)-/(E)-Anisaldehyde-Based Oxime Ester Compounds

In search of novel natural product-based bioactive molecules, twenty (ten pairs) novel (Z)-/(E)-anisaldehyde-based oxime ester compounds were designed and synthesized by using anisaldehyde as starting material. Structural characterization of the target compounds was carried out by NMR, FT-IR, ESI-MS, and elemental analysis. Their herbicidal and antifungal activities were preliminarily tested. As a result, at 50 μg/mL, compound (E)- 5b exhibited excellent to good inhibition rates of 92.3 %, 79.2 %, and 73.9 %, against Rhizoctonia solani, Fusarium oxysporum f. sp. cucumerinum, and Bipolaris maydis, respectively, better than or comparable to that of the positive control chlorothalonil. In addition, at 100 μg/mL, compounds (E)- 5b , (E)- 5f , (Z)- 5f and (E)- 5d exhibited excellent to good inhibition rates of 85.8 %, 82.9 %, 78.6 % and 64.2 %, respectively, against the root-growth of rape (B. campestris), much better than that of the positive control flumioxazin. The bioassay result also showed that the synthesized compounds had obvious differences in antifungal and herbicidal activities between (Z)- and (E)-isomers. Preliminary structure–activity relationship was also discussed by theoretical calculation.     

Metabolism of (2Z,4E)-γ-Ionylideneethanol and (2Z,4E)-γ-Ionylideneacetic Acid in Cercospora cruenta

[2–¹⁴C]-(2Z,4E)-γ-Ionylideneethanol and [2–¹⁴C]-(2Z,4E)-γ-ionylideneacetic acid were converted by Cercospora cruenta to [2–¹⁴C]-(2Z,4E)-1′,4′-dihydroxy-γ-ionylideneacetic acid and [2-¹⁴C]-(2Z,4E)-4′-hydroxy-γ-ionylideneacetic acid, which are intermediates of ABA biosynthesis in C. cruenta.     

A chemosystematically significant 6,8,11-trihydroxygermacrane derivative from the New Zealand Apiaceae Anistome pilifera

Roots of Anisotome pilifera yielded typical Apiaceae compounds 6,7-dimethoxy-coumarin 1 and falcarindiol 2, plus the irregular diterpenes anisotomenoic acid 3 and anisotomene alcohol 4. The new germacrane derivative 8-O-senecioyl-6β,8α,11-trihydroxygermacra-1(10)E,4E-diene 5 was also isolated and the structure established by means of high resolution mass spectrometry and 1-D and 2-D NMR spectroscopy. Distribution and chemosystematic significance of 6,8-dihydroxygermacra-1(10)E,4E-dienes and 6,8,11-trihydroxygermacra-1(10)E,4E-dienes are discussed. Additionally, leaves of A. pilifera yielded chlorogenic acid 6 and high amounts of luteolin 7-O-α- -rhamnosyl(1→6)-β- -glucoside 7.     

Cynasibirolide A,One New Humulanolide Sesquiterpene from Cynanchum acutum subsp. sibiricum

Cynasibirolide A ( 1 ), one new humulanolide sesquiterpene, together with four known analogs, asteriscanolide ( 2 ), (1S,8S)-8-hydroxyhumula-2Z,6E,9E-trien-1,12-olide ( 3 ), (1S,7R)-8-oxohumula-2Z,9E-dien-1,12-olide ( 4 ), and (+)-6,7,9,10-tetrahydroasteriscunolide ( 5 ) were isolated from the roots and rhizomes of Cynanchum acutum subsp. sibiricum. Their structures and configurations were elucidated by spectroscopic methods, including 2D-NMR techniques, and the structure of 1 was confirmed by single-crystal X-ray diffraction. All compounds were evaluated for their anti-complementary activity in vitro, and compound 3 exhibited anti-complement effect with CH₅₀ value of 0.45 mM.     

Revisiting the trail pheromone components of the red imported fire ant,Solenopsis invicta Buren

Ants use species-specific trail pheromones to coordinate their sophisticated foraging behavior. During the past decades, many trail pheromone components with various structures have been identified in ants, including the red imported fire ant, Solenopsis invicta, a notorious invasive species worldwide. Four compounds, Z,E- (ZEF) and E,E-α-farnesene (EEF), Z,E- (ZEHF) and E,E-α-homofarnesene (EEHF), have been reported as components of S. invicta trail pheromone. However, another study reported an analog of α-farnesene, Z,Z,Z-allofarnesene, as a key trail pheromone component. These contrasting results caused some uncertainty about the trail pheromone composition in S. invicta. In this study, we synthesized ZEF and EEF, ZEHF and EEHF, and reanalyzed the chemicals in the Dufour gland extract and in the trail pheromone fraction of S. invicta worker body extract. The reported isomers of farnesene and homofarnesene were detected and showed trail-following activity, with ZEF as the major compound, while no allofarnesene was found, neither in the Dufour gland extract nor in the whole-body extract. Our results confirm ZEF and EEF, ZEHF and EEHF as trail pheromone components of S. invicta.     

Utilization of Bacterial Xanthine Oxidase for Inorganic Phosphorus Determination

Two host-specific phytotoxic metabolites, AK-toxin I and II, were isolated from a culture broth of Alternaria alternata Japanese pear pathotype, the fungus causing black spot disease of susceptible Japanese pear cultivars. From chemical, spectral and X-ray crystallographic data, AK-toxin I was characterized as 8-(2′S, 3′S)-2′-acetylamino-3′-methyl-3′-phenyl-propionyloxy]-(8R,9S)-9,10-epoxy-9-methyl-deca-(2E,4Z,6E)-trienoic acid. The structure of AK-toxin II was also assigned to be 3′-demethyl derivative of AK-toxin I by comparing the spectral data with those of AK-toxin I.     

Enantiotopically Selective Oxidation of 1,5-Diols with Gluconobacters Preparation of (S)-Mevalonolactone

(±)-(2Z,4E)-α-Ionylideneacetic acid (2) was enantioselectively oxidized to (?)-(l′S)-(2Z,4E)-4′-hydroxy-α-ionylideneacetic acid (3), (+)-(1′R)-(2Z,4E)-4′-oxo-α-ionylideneacetic acid (4) and (+)-abscisic acid (ABA) (1) by Cercospora cruenta IFO 6164, which can produce (+)-ABA and (+)-4′-oxo-α-acid 4. This metabolism was confirmed by the incorporation of radioactivity from (±)-(2-¹⁴C)-(2Z,4E)-α-acid 2 into three metabolites. (?)-4′-Hydroxy-α-acid 3 was a diastereoisomeric mixture consisting of major 1′,4′-trance-4′-hydroxy-α-acid 3a and minor 1′,4′-cis-4′-hydroxy-α-acid 3b. These structures, 3a and 3b, were confirmed by ¹³C-NMR and ¹H-NMR analysis. Also, the enantioselectivity of the microbial oxidation was reexamined by using optically pure α-acid (+)-2 and (?)-2, as the substrates.     

Design, synthesis and in vitro evaluation of novel chroman-4-one, chroman, and 2H-chromene derivatives as human rhinovirus capsid-binding inhibitors

As part of an effort to generate broad-spectrum inhibitors of rhinovirus replication, novel series of (E)-3-[(E)-3-phenylallylidene]chroman-4-ones 1a–e, (E)-3-(3-phenylprop-2-yn-1-ylidene)chroman-4-ones 2a and 2b, (Z)-3-[(E)-3-phenylallylidene]chromans 3a–e, and (E)-3-(3-phenylprop-1-en-1-yl)-2H-chromenes 4a–d were designed and synthesized. All the compounds were tested in vitro for their efficacy against infection by human rhinovirus (HRV) 1B and 14, two representative serotypes for rhinovirus group B and A, respectively. Most of the analogues were found to be potent and selective inhibitors of both HRVs, although HRV 1B was generally more susceptible than HRV 14. Mechanism of action studies of (E)-6-chloro-3-(3-phenylprop-1-en-1-yl)-2H-chromene 4b, the most potent compound on HRV 1B infection, suggested that 4b behaves as a capsid-binder probably acting at the uncoating level.     

Attraction of codling moth males to apple volatiles

The attraction of the codling moth, Cydia pomonella, to apple volatile compounds known to elicit an antennal response was tested both in the field and in a wind tunnel. In the field, (E)‐β‐farnesene captured male moths. The addition of other apple volatiles, including (E,E)‐α‐farnesene, linalool, or (E,E)‐farnesol to (E)‐β‐farnesene did not significantly augment trap catch. Few females were caught in traps which also caught male moths, but female captures were not significantly different from blank traps. In the wind tunnel, males were attracted to (E,E)‐farnesol, but not to (E)‐β‐farnesene. The addition of (E,E)‐α‐farnesene to (E)‐β‐farnesene had a synergistic effect on male attraction. The male behavioural sequence elicited by plant volatiles, including upwind flight behaviour, was indistinguishable from the behaviour elicited by sex pheromone.     

Syntheses,Characterizations, and Biological Activities of Tetradeca‐4,8‐dien‐1‐yl Acetates as Sex Attractants of Leaf‐Mining Moth of the Genus Phyllonorycter (Lepidoptera: Gracillariidae)

The four possible isomers of tetradeca‐4,8‐dien‐1‐yl acetate and corresponding alcohols were synthesized stereoselectively by synthetic routes employing Wittig coupling reaction for the preparation of (Z,E)‐ and (Z,Z)‐isomers, and alkylation of terminal alkynes for the preparation of (E,E)‐ and (E,Z)‐isomers as the key steps. Synthetic products were characterized by ¹³C‐ and ¹H‐NMR spectroscopy as well as mass‐spectrometric methods. All four isomers gave distinctive mass spectra where m/z 81 fragments clearly dominated. Elution order, followed by retention index presented in parenthesis, of tetradeca‐4,8‐dien‐1‐ols was determined as (Z,Z) (2082.1), (Z,E) (2082.8), (E,E) (2083.1), and (E,Z) (2083.2) from unpolar SPB‐1 column, and as (E,E) (2210.2), (Z,E) (2222.1), (E,Z) (2223.4), and (Z,Z) (2224.7) from polar DB‐WAX column. The isomers of tetradeca‐4,8‐dien‐1‐yl acetates eluted in the order of (Z,Z) (2176.1), (Z,E) (2178.4), (E,Z) (2185.9), and (E,E) (2186.4) from SPB‐1, and (Z,E) (2124.3), (E,E) (2157.7), (Z,Z) (2128.9), and (E,Z) (2135.9) from DB‐WAX columns. Field‐screening tests for attractiveness of tetradeca‐4,8‐dien‐1‐yl acetates revealed that (4Z,8E)‐tetradeca‐4,8‐dien‐1‐yl acetate significantly attracted Phyllonorycter coryli and Chrysoesthia drurella males. (4E,8E)‐Tetradeca‐4,8‐dien‐1‐yl acetate was the most efficient attractant for Ph. esperella and Ph. saportella males, and (4E,8Z)‐tetradeca‐4,8‐dien‐1‐yl acetate was attractive to Ph. cerasicolella males.