Search

Both enantiomers of ( P )-(+)-2- and ( M )-(−)-2-acetoxy-11,14-dimethyl[5]helicenes 8 were synthesized by asymmetric aromatic oxy-Cope rearrangement of the corresponding chiral bridged bicyclic compounds, which were obtained by enzymatic resolution. The absolute configurations of 8 were assigned by their circular dichroism spectra.

An efficient one-pot synthesis of a 10,10-ethylenebicyclo[5.2.1]dec-8-en-4-one derivative, which can be considered as a synthetic intermediate for the taxane skeleton, has been achieved by tandem anionic [1,3] and oxy-Cope rearrangements of 2-vinylbicyclo[3.2.1] oct-6-en-2-ol.

The anionic [1,3] rearrangement of both stereoisomeric bicyclo[3.2.1]oct-6-en-2-ols by treatment with KN(TMS) 2 in toluene or in diglyme took place as a stereoconvergent route giving each of the stereoisomeric hydroxydiquinanes.

The aromatic oxy-Cope rearrangement including a benzene ring took place when 1-methoxy-2-aryl-bicyclo[2.2.2]oct-5-en-2- exo -ols and 2-(2-methoxyphenyl)-bicyclo[2.2.2]oct-5-en- exo -2-ols were treated with KH in THF.

Oxidative coupling reaction of both 3-hydroxychrysene and 2-hydroxybenzo[c]phenanthrene by using Cu(NO3)2–3H2O under atmospheric air is described. The former gave the aimed coupled biaryl derivative. However, the latter gave a further oxidized helical quinone derivative. The unique helical structure was characterized by X-ray and NMR analysis.

The Lewis acid mediated reactions of allenylstannanes 1 and 13 gave trans cyclic ethers 3a and 14, respectively, with high stereoselectivities. The cyclization fo 7 gave trans cyclic ether 9a. The treatment of propargylstannanes 2 and 8 with Lewis acids such as SnCl4, BuSnCl3, and ZnCl2·OEt2 induced isomerization to allenylmetal species, which underwent cyclization to the corresponding 6- and 5-membered cyclic ethers 3 and 9, respectively. The stereoselectivities depended upon the ring size and Lewis acid utilized.

Ten new (+)-hydroxybutanolides, linderanolides A-E and isolinderanolides A-E, along with one known one have been isolated from the leaves of Lindera glauca. On the basis of spectroscopic methods and chemical evidence, linderanolides A-E were shown to be (3R,2Z)-3-hydroxy-4-methylenebutanolides having 2-((11E)-11-tetradecenylidene), 2-tetradecylidene, 2-((7Z,10Z)-7,10-hexadecadienylidene), 2-((7Z)-7-hexadecenylidene) and 2-hexadecylidene side-chains, respectively, while isolinderanolides A-E were their corresponding (2E)-isomers.

Three new compounds, along with four known ones, have been isolated from the seeds of Iris pallasii . On the basis of spectroscopic methods and chemical evidence, the new compounds were shown to be 2-[(Z)-10-heptadecenyl]-4,6-dimethoxyphenol, 3,5-dimethoxy-[(Z)-10-heptadecenyl]benzene and 9,9b-di[(Z)-10-heptadecenyl]-4a,8-dihydroxy-2,7-dimethoxy-1,4-dioxo-1,4,4a,9b-tetrahydrodibenzofuran. The biogenetic relationships between these compounds are also discussed.

Four new enediones, belamcandones A-D, have been isolated from the seeds of Belamcanda chinensis . On the basis of spectroscopic methods and chemical evidence, they are concluded to be 4a,8-dihydroxy-2,7-dimethoxy-1,4-dioxo-1,4,4a,9b- tetrahydrodibenzofurans having two alkyl side-chains at the C-9 and C-9b positions.

Eight tetracyclic spirotriterpene derivatives, iristectorones A-H, have been found in the seeds of Iris tectorum . Their structures were established to be the Diels-Alder products of 2-methoxy-6-[( Z )-10-pentadecenyl]- p -benzoquinone with triterpenic conjugated trienes having spiro [4.5] decane skeleton derived from iristectorenes A-H, respectively, on the basis of spectral methods and chemical transformations. A possible biogenetic route for these esters has been also discussed.

Six new triterpene esters, iristectorenes A and C-G, along with one known one have been found in the seeds of Iris tectorum . On the basis of spectroscopic methods and chemical evidence, the esters were established to be 3-{3-hydroxy-2-[5-hydroxy-4,8,12-trimethyl-(3 E ,7 E )-3,7,1 1-tridecatrienyl]-2,3-dimethyl-6-(1-methyl-2-oxoethylidene)-cyclohexyl}propyl ( Z )-9-tetradecenoate,( Z )-11-hexadecenoate, ( Z,Z )-9,12-octadecadienoate, hexadecanoate, ( Z )-11-octadecenoate and octadecanoate, respectively.

The synthesis of unique diquinanes, possessing four continuous methyl groups on the convex of the diquinane skeleton, has been achieved by employing a combination of pinacol-type rearrangement and efficient anionic [1,3] rearrangement strategies.

アイソタクチックポリプロピレンの塩素化を行い, 13CNMRスペクトルを用いて塩素の置換位置の定量を行った. シグナルの定量性の確認のために, 反転回復法によりT1を測定をした. 定量計算の基本スペクトルはNOEの影響のないゲートデカップリング付13CNMR法によって得た. シグナルの分離は, 前報に述べたINEPTのJ変調法を用いて行った. また4級炭素のピーク形状および化学シフトの確認のため, APTのJ変調により4級炭素のシグナルを分離した. この結果ポリプロピレンの3級炭素の塩素化によるシフトファクターは47ppmであった. 36. 0% (wt/wt) 塩素化ポリプロピレンの分析結果は, R3CCI: R2CHCI: RCH2Cl: RCHCl2=1. O: 3. 9: 3. 1: 0. 1であった. この結果より得られる塩素組成の値を元素分析値と比較すると1%の誤差で一致しており, J変調によるシグナルの分類がこの種の高分子物質の構造解析に有益であることを確認した.

The Lewis acid mediated reactions of allenylstannanes 1 and 13 gave trans cyclic ethers 3a and 14, respectively, with high stereoselectivities. The cyclization fo 7 gave trans cyclic ether 9a. The treatment of propargylstannanes 2 and 8 with Lewis acids such as SnCl4, BuSnCl3, and ZnCl2·OEt2 induced isomerization to allenylmetal species, which underwent cyclization to the corresponding 6- and 5-membered cyclic ethers 3 and 9, respectively. The stereoselectivities depended upon the ring size and Lewis acid utilized.

Treatment of 2-vinylbicyclo[3.2.1]oct-6-en-2-ols with KH in toluene gave mainly [5-5] fused-ring compounds through a [1,3] sigmatropic shift.

The aromatic oxy-Cope rearrangement including a benzene ring took place when 1-methoxy-2-aryl-bicyclo[2.2.2]oct-5-en-2- exo -ols and 2-(2-methoxyphenyl)-bicyclo[2.2.2]oct-5-en- exo -2-ols were treated with KH in THF.

The anionic [1,3] rearrangement of both stereoisomeric bicyclo[3.2.1]oct-6-en-2-ols by treatment with KN(TMS) 2 in toluene or in diglyme took place as a stereoconvergent route giving each of the stereoisomeric hydroxydiquinanes.

The synthesis of unique diquinanes, possessing four continuous methyl groups on the convex of the diquinane skeleton, has been achieved by employing a combination of pinacol-type rearrangement and efficient anionic [1,3] rearrangement strategies.

An efficient one-pot synthesis of a 10,10-ethylenebicyclo[5.2.1]dec-8-en-4-one derivative, which can be considered as a synthetic intermediate for the taxane skeleton, has been achieved by tandem anionic [1,3] and oxy-Cope rearrangements of 2-vinylbicyclo[3.2.1] oct-6-en-2-ol.

In the course of studies on the iodine-sensitized conjugation of 1, 4-diene compounds, the effects of iodine compounds on this reaction were investigated. A solution containing 10% methyl linoleate and iodine compound (0.1% : calcd. for I2) in petroleum ether was irradiated with a 100 W high-pressure mercury lamp for 8 h.Iodine compounds, especially CHI3, CH2I2, IBr, ICl, (CH3) 2CHI, ICl3 and C6H5I, were found effective for this sensitized reaction. Methyl linoleate was converted to conjugated dienoates in approximately 80% yields along with small quantities of methyl trans-octadecenoates and dimers. The ratio of cis, trans-, cis, cis- and trans, trans-forms was 8 : 1 : 24 in the conjugated dienes. Conjugation with CH3I was quite slow, the yield being 10% after 8 h.The activities of iodine compounds in this sensitized reaction decrease in the following order : CHI3 ≥ I2 ≥CH2I2 ≥ IBr ≥ ICl > (CH3) 2CHI ≥ ICl3 ≥ C6H5 I>p-CH3C6H4I >> CH3 (CH2) 3I > CH3 (CH2) 2I >> CH3CH2I > CH3IThe rates of conjugation of methyl linoleate thus appear closely correlated to the dissociation energies of the I-X bonding (X=C, Cl, Br, I) and absorption spectra of iodine compounds.This isomerization proceeds fundamentally in the same way as noted in the previous paper. That is, an iodine compound first dissociates with light, and conjugation subsequently proceeds through a radical mechanism involving a bridged iodoalkyl radical.

Monolayer properties of irisresorcinol [5-(cis-10-heptadecenyl) resorcinol] were measured at the air/water interface. TheA-T isobars of the monolayers at 10 and 15 mN/m gave two-dimensional thermal expansivities of 1.4 × 10−4/K and 1.3 × 10−4/K at a temperature span from 7–40 ‡C, respectively. Theπ- A isotherms of the material showed only a little dependence on temperature from 5–35 ‡C and onpH except at highpH, where monolayers expanded by ionization of resorcinol headgroups. Some types of saccharose in the subphase exhibited a characteristic interaction with irisresorcinol in monolayers, and there is a possibility that this material will be used for molecular recognition of some saccharoses.

Two (-)-methoxybutanolides have been isolated from the rhizomes of Lindera glauca . On the basis of spectroscopic methods, their structures were elucidated to be (3 S ,2 E )-2-(11-dodecenylidene)-3-methoxy-4-methylenebutanolide and (3 S ,2 E )-2-(11 -dodecynylidene)-3-methoxy-4-methylenebutanolide, respectively.

Two malate dehydrogenases (MDH-M1 and MDH-M2) were found in a methanol-using yeast, Candida sp. N-16. MDH-M2 was induced with methanol. These enzymes were purified as electrophoretically and isoelectrophoretically homogeneous proteins. The molecular weights of MDH-M1 and MDH-M2 were estimated to be about 78,000 (homodimer) and 160,000 (homotetramer). Several kinetic properties were significantly different between the two enzymes. The value (2.07) of Vmax(oxaloacetate)/Vmax(malate) and Kcats (555 s(-1) for oxaloacetate, 481 s(-1) for NADH) of MDH-M2 were higher than the ratio (1.37) of Vmax and Kcats (241 s(-1) for oxaloacetate, 271 s(-1) for NADH) of MDH-M1, respectively. The activity of MDH-M2 was inhibited by a high concentration of NAD+ and the activity of MDH-M1 by oxaloacetate.

Treatment of 2-vinylbicyclo[3.2.1]oct-6-en-2-ols with KH in toluene gave mainly [5-5] fused-ring compounds through a [1,3] sigmatropic shift.

In the previous paper, we reported the optimum conditions for the iodine-sensitized conjugation of methyl linoleate and its reaction mechanism.This paper discusses isomerization arising from irradiation with a 100W high-pressure mercury lamp using methyl linolenate with a 1, 4, 7-triene structure. Conjugated diene-trienoates and small amounts of conjugated trienoates are formed in this reaction. Slightly milder conditions than in methyl linoleate are suitable for the formation of conjugated diene-trienoates. The reaction conducted at room temperature using a sample with a concentration of 10 to 20% adding approximately 0.1% of iodine to a nonpolar solvent such as petroleum ether by irradiation for 46h is considered optimum. To obtain conjugated trienoates mainly, however, milder conditions such as no more than 0.03% iodine should be used. Under such conditions, the amounts of conjugated compounds were as much as about 70% (conjugated diene-trienoates 5562%; conjugated trienoates 815%) of the reaction products.This sensitized isomerization proceeds in the same way as indicated in the previous report and double bonds shift only in the direction of the conjugation.

Monolayers of irisquinone, trans-irisquinone, dihydroirisquinone, 3-hydroxyirisquinone, 3-hydroxydihydroirisquinone, and their corresponding unsaturated long-chain alcohols were studied using pressure-area (π-A) isotherms. All the materials studied form stable monolayers at the air/water interface and the characteristic molecular arrangements of the quinone derivatives in monolayers were presumed from the π-A isotherms. The contribution of the hydrophilic quinone headgroups and the hydrophobic alkyl chains to the characteristic molecular arrangements was discussed. Three of the five types of the materials exhibit the liquid-expanded/liquid-condensed transitions with compression at certain temperature regions. A thermodynamic treatment was applied to the transitions.

The role of irisquinone (IQ) in the chlorophyll-IQ electrode was studied by measuring the photoresponse under illumination and the photocurrent at the controlled potential. It was concluded that the hydrophobic property of IQ was necessary for the photoresponse to occur at the chlorophyll electrode, and that the photoexcited chlorophyll was likely to eject electrons to a counter electrode via an outer circuit and to pull electrons from the reduced IQ, which had been produced by the oxidation of a reducing compound in the electrolyte on the chlorophyll-IQ electrode.

Sesquiterpene hydrocarbons from the seed oil of Iris tectorum M. were investigated. Fractionation of the hexane extract of the seeds by column chromatography on activated alumina and steam distillation gave monoterpene-free hydrocarbons which showed approximately thirty peaks by capillary gas chromatography. A combination of techniques including a silver nitrate addition procedure, rectification and silver nitrate-impregnated silica gel column chromatography was used to separate the sesquiterpenes.Twenty-four compounds could be identified on the basis of spectral data (IR, NMR, GC, GC-MS) and chemical transformations. The main components were germacrene D (45%), alloaromadendrene (12%), δ-, γ-cadinene (13%), and β-caryophyllene (7%). These sesquiterpenes in Iridaceae plants were characterized for the first time in the present research.

In the course of studies on the iodine-sensitized photoconjugation of 1, 4-diene compounds, the effects of terminal functional groups on this reaction were investigated. Linoleic acid and its related compounds, such as methyl linoleate, linoleyl alcohol, linoleyl acetate and cis-6, cis-9-octadecadiene derived from linoleic acid, were used as samples.Based on the results of sensitized isomerization, the carboxyl group was without any effect whatsoever. Linoleic acid reacted at the same rate as 6, 9-octadecadiene, or faster than that of methyl linoleate, so that maximum equilibrium was attained within 1h. Moreover, the photo-conjugation of linoleyl acetate occurred more slowly than that of methyl linoleate. The amounts of the conjugated compounds were about as much as 80% in either case. With linoleyl alcohol, isomerization was quite slow, the yield being about 10% after 8h. This is in agreement with the finding that this sensitized conjugation does not proceed in a polar solvent such as ethanol.Therefore, the reactivities of the end-groups on this iodine-sensitized reaction decrease in the following order : CH3≥COOH>COOCH3>CH2OCOCH3>>CH2OH.This reaction apparently occurs through a radical mechanism involving a bridged iodoalkyl radical as an intermediate. The products mainly consisting of cis, trans- and trans, trans-conjugated dienes were thus obtained at a ratio of about 3 : 7.