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1.
From the hot petrol extract of Piper cubeba ftuits, six lignans were isolated. Two of these, which have been obtained from a natural source for the first time, have been characterized as (2R,3R)-2-(3″,4″,5″-trimethoxybenzyl)-3-(3′,4′-methylenedioxybenzyl)-1,4-butanediol [(?)-dihydroclusin] and (3R,4R)-3,4-bis-(3,4,5-trimethoxybenzyl)tetra-hydro-2-furanol [(?)-cubebinin]. (?)Cubebin, (?)-hinokinin, (?)-clusin and (?)-dihydrocubebin were also found in this plant. Only (?)-cubebin has been reported so far from this source. 相似文献
2.
The Wittig reaction of (?)-α-ionone (VIa) with carbethoxymethylenetriphenylphosphorane afforded (?)-ethyl α-ionylideneacetate (VIIa). tert-Butyl chromate oxidation of the above ester (VIIa) gave (?)-ethyl 4′-keto-α-ionylideneacetate (VIlla). Selenium dioxide oxidation of (?)-α-ionone (IVa) in ethanol afforded (?)-1′-hydroxy-α-ionone (X), which reacted with car-bethoxymethylenetriphenylphosphorane to give (?)-ethyl 1′-hydroxy-α-ionylideneacetate (XI). tert-Butyl chromate oxidation of the hydroxy-ester (XI) gave (?)-ethyl abscisate (XII) and ethyl 3′-keto-β-ionylideneacetate (XIII). The sensitized photooxidation of ethyl dehydro-β-ionylideneacetate (XVI) using chlorophyll was attempted. 相似文献
3.
Reduction of (?)-menthone ((?)- 1 ), (+)-(R)-methyl-α-campholenone ((+)- 2 ), (+)-carvone ((+)- 3 ), and eucarvone ( 4 ) was carried out by means of cells of the Rhodotorula mucilaginosa species immobilized in polyacrylamide gel. Alcohols with the (S)-configuration, (+)-neomenthol ((+)- 1a ), (+)-(R)-methyl-α-campholenol ((+)- 2a ), (?)-neoisodihydrocarveol ((?)- 3a ), dihydroeucarveol ((?)- 4a ), and small amounts of (?)-dihydroeucarvone ((?)- 5 ), were obtained. The cells of R. mucilaginosa maintained after this reaction ability to reduce standard acetophenone to (?)- 1 -phenyl- 1 -ethanol. 相似文献
4.
Absolute configurations have been assigned to the enantiomers of the antimalarial drug quinacrine dihydrochloride. Condensation of (?)-(R)-4-amino-1-diethylaminopentane (from L -glutamic acid) with 6,9-dichloro-2-methoxyacridine gave (?)-(R)-6-chloro-9-(4′-diethylamino-1′-methylbutyl) amino-2-methoxyacridine [(?)-(R)-quinacrine] while (+)?(S)-quinacrine was obtained from the enantiomeric diamine. 相似文献
5.
《Bioscience, biotechnology, and biochemistry》2013,77(9):2106-2109
The synthesis of methyl (?)-shikimate [(?)-2] was achieved via lipase-catalyzed optical resolution of (1S*,4R*,5R*)-4-hydroxy-6-oxabicyclo[3.2.1]oct-2-en-7-one (3). Transesterification of (±)-3 and vinyl acetate with lipase MY and subsequent hydrolysis gave optically pure (?)-3. This compound was converted to (?)-2 in two steps. 相似文献
6.
N-(3′,4′-Dihydroxy-trans-cinnamoyl)-3-(3,4-dihydroxyphenyl)-L-alanine [(?)-clovamide], the major phenolic metabolite (0.1%) in the bark of Dalbergia melanoxylon, is associated with minor proportions of its cis-isomer, and similar pairs of geometrical isomers of their deoxy analogues N-(4′-hydroxycinnamoyl)-3-(3,4-dihydroxyphenyl)-L-alanine and N-(4′-hydroxycinnamoyl)-3-(4-hydroxyphenyl)-L-alanine. (?)-Trans-clovamide is synthesized by direct condensation of the acid chloride of caffeic acid with L-DOPA. Diagnostic CD spectra of these compounds and 13C spectra of (?)-trans- and (?)-cis-clovamides are recorded. 相似文献
7.
G. Subramaniam Kenny K.H. Ang Siewbee Ng Antony D. Buss Mark S. Butler 《Phytochemistry letters》2009,2(2):88-90
A new benzopyrroloisoquinoline alkaloid, fistulosine (1), was isolated from the stem-bark of Ficus fistulosa (Moraceae) collected in Singapore, along with three known phenanthroindolizidine alkaloids, (?)-13aα-antofine (2), (?)-14β-hydroxyantofine (3) and (?)-13aα-secoantofine (4). (?)-13aα-Antofine (2) accounted for the antifungal activity against Aspergillus fumigatus and Candida albicans originally observed in the crude alkaloid extract. 相似文献
8.
Berit Backlund Hk Anette M. Johansson Stephan Hjorth Staffan Sundell Uli Hacksell 《Chirality》1993,5(3):112-119
Racemic 5-methoxy-2-methyl-2-dipropylaminotetralin ( 3 ) has been prepared by a short synthetic route, in which the N,N-dipropyliminium perchlorate of 5-methoxy-2-tetralone ( 4 ) is a key intermediate. Racemic 3 was resolved by crystallization of the corresponding diastereomeric di-p-toluoyltartrates. The enantiomeric excess (%ee) of the phenolic derivatives of (+)-(R)- and (?)-(S)-3 [(+)-(R)- and (?)-(S)-2] was determined by 1HNMR spectroscopic analysis of the corresponding diastereomeric (?)-(R)-1,1′-binaphthyl-2,2′-diylphosphoric acid salts utilizing 13C satellites. X-ray crystallography established the absolute configuration of (?)-(S)-2 · HCl. The enantiomers of 2 were tested for hippocampal output of 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, and dihydroxyphenylacetic acid in rats by use of in vivo microdialysis. The (?)-(S)-enantiomer appeared to affect 5-HT-turnover, whereas (+)-(R)- 2 was inactive. Results obtained provide support for the previously reported hypothesis that the inactivity of (?)-(S)- 2 at central DA receptors is caused by the steric bulk of the C(2)-methyl group. This makes it possible to define a “DA D2 receptor essential volume.” © 1993 Wiley-Liss, Inc. 相似文献
9.
Hydroxychloroquine (HCQ) stereoselective distribution was investigated in rabbits after 20 mg/kg po of racemic-HCQ (rac-HCQ) and 20 mg/kg po of each enantiomer, 97% pure (?)-(R)-HCQ and 99% pure (+)-(S)-HCQ. Concentrations were 4 to 6 times higher in whole blood than in plasma. Melanin did not affect plasma and whole blood levels since concentrations did not differ between pigmented and nonpigmented animals. After single and multiple doses of the separate enantiomers, only 5–10% of the antipode could be measured, in blood or plasma. Therefore, there was no significant interconversion from one enantiomer into the other. Following rac-HCQ, plasma (+)-(S)-levels always surpassed (?)-(R)-ones while in whole blood, (?)-(R)-HCQ concentrations were always the highest. When the enantiomers were administered separately, blood concentrations achieved after (?)-(R)-HCQ were higher, especially after multiple doses. These observations suggest that (?)-(R)-HCQ is preferentially concentrated by cellular components of blood. This enantioselective distribution of HCQ could be secondary to a stereoselective protein binding to plasma proteins, although a more specific binding of (?)-(R)-HCQ to blood cells cannot be ruled out. Since in whole blood (?)-(R)-HCQ is retained in cellular components, metabolism would favour the more available (+)-(S)-enantiomer. © 1994 Wiley-Liss, Inc. 相似文献
10.
Enzyme extracts of the wild type yeast Zygosaccharomyces bisporus were applied for the pyruvate decarboxylase catalysed condensation of pyruvate and (R)-(+)-and (S)-(?)-perillyl aldehyde, (±)-citronellal, neral, geranial or (R)-(?)-myrtenal to form novel α-hydroxy ketones. Best yields were obtained when the transformation medium contained 25% (v/v) of the cosolvent N,N-dimethylformamide. Conversion of (R)-(+)-perillyl aldehyde to (1R)-1-hydroxy-1-[(4’R)-4’-isopropenyl-1-cyclohexen-1-yl]-2-propanone proceeded highly stereospecifically (>99% de), whereas the stereoselectivity was somewhat less in the transformation of (S)-(?)-perillyl aldehyde (58% de) and (R)-(?)-myrtenal (92% de). All of the new compounds imparted characteristic odour impressions as determined by means of GC-olfactometry. 相似文献
11.
Sachio Kudo Takayuki Oritani Kyohei Yamashita 《Bioscience, biotechnology, and biochemistry》2013,77(11):2739-2743
Such (+)- and (?)-cis-cycloheximide isomers as isocyclohcximide (1a, 1b), α-epiisocycloheximide (2a, 2b) and neocycloheximide (3a, 3b) were synthesized by aldol condensation of (?)-(2R, 4R)- and (+)-(2S, 4S)-cis-2,4-dimethyl-1-cyclohexanone (5a, 5b). obtained by microbial resolution, with 4-(2-oxoethyl)-2,6-piperidinedione (7). The absolute configuration of the (?)-cis-ketone 5a was confirmed by chemical correlation with natural (2S, 4S, 6S, αR)-cycloheximide (4). The newly synthesized isomer, (?)-α-epiisocycloheximide (2b), showed strong antimicrobial activity against S. cerevisiae andP. oryzae close to that of natural cycloheximide (4). 相似文献
12.
The relative configuration of the enantiomers of thioridazine was defined to explore the stereochemistry associated with the selective binding of (?)-thioridazine to dopamine D-1 receptors and (+)-thioridazine to D-2 receptors. Using a seven-step stereoconservative synthesis, (?)-(S)-2-piperidinecarboxylic acid was converted to (?)-(S*)-2-(2-chloroethyl)-1-methylpiperidine, a literature (?)-thioridazine synthetic precursor. Accordingly, (?)- and (+)-thioridazine are the (S)- and (R)-enantiomers, respectively. 相似文献
13.
The wood of Virola carinata (Benth.) Warb. contains besides the known neolignans (+)-guaiacin and (?)-galcatin, (?)-isootobaphenol [(2R,3S,4S)-4-guaiacyl-2,3-dimethyl-6,7-methylenedioxytetralin], in addition to 7,4′-dimethoxyflavanone. 相似文献
14.
Chiral (+)- and (?)-enantiomers of (2Z,4E)-5-(1′,2′-epoxy-2′,6′,6′-trimethylcyclohexyl)-3-methyl-2,4-pentadienoic acid have been synthesized from the chiral epoxy alcohols (+)- and (?)-1′,2′-dihydro-1′,2′-epoxy-β-ionone, which were prepared by Katsuki-Sharpless' asymmetric epoxidation of β-cyclogeraniol. The (+)-enantiomer showed strong inhibitory activity in a rice seedling and lettuce germination assay, whereas the (?)-enantiomer was 103-times less active. 相似文献
15.
Three new sesquiterpene alcohols have been isolated from Jasonia glutinosa. Their structures were elucidated by spectroscopic methods and chemical correlations as (?)-[11R]-4α,14-epoxyeudesm-11,12-diol, (?)-[11R]-eudesm-4(14)-en-5β,11,12-triol and (+)-[11R]-eudesm-4(14)-en-5α,11,12-triol and they are called α-epoxy kudtdiol, 5-epi-kudtriol and kudtriol respectively. 相似文献
16.
(?)-Cryptocaryalactone (6-[2-acetoxy-4-phenyl-3-butenyl]-5,6-dihydro-2-pyranone) and (?)-deacetylcryptocaryalactone (6-[2-hydroxy-4-phenyl-3-butenyl]-5,6-dihydro-2-pyranone) isolated from Cryptocarya moschata seeds are natural germination inhibitors. Applied at 0.004 M, the second compound completely arrested germination of velvetleaf (Abutilon theophrasti) and decreased the germination rate of soybeans, but did not appear to affect corn. The first compound was not as effective; 0.004 M reduced velvetleaf germination 50%. 相似文献
17.
Chia-Jung Chen R. Vijaya Krishna Chia-Che Tsai Wan-Hsun Wu Louis Kuoping Chao Kent-Hao Hwang Chichen Michael Chien Hwan-You Chang Shui-Tein Chen 《Bioorganic & medicinal chemistry》2010,18(18):6896-6904
The preserved fungal species Antrodia camphorata has diverse health-promoting effects and has been popularly used in East Asia as a traditional herb. We isolated a volatile compound from the culture medium of A. camphorata and identified it as γ-dodecalactone (γ-DDL). Cytomic screening for immune-modulating activity revealed that γ-DDL can activate human NK cells to express the early activation marker CD69. Further experiments showed that γ-DDL not only can induce NK cells to express CD69 but also stimulate NK cells to secrete cytotoxic molecules (FasL and granzyme B) and Th1 cytokines (TNF-α and INF-γ).Measuring the distribution of γ-DDL in the subcellular compartments of NK cells revealed that γ-DDL has been converted to 4-hydroxydodecanoic acid (an acyclic isomer of γ-DDL) in a time-dependent manner in the cytoplasm.Synthetic (R,S)-4-hydroxydodecanoic acid activated NK cells to express CD69 mRNA within 10 min, in contrast to γ-DDL, which activated NK cells to express CD69 within 50 min. This faster activation suggests that γ-DDL has converted to 4-hydroxydodecanoic acid and to stimulate the NK cells to express CD69.Optically pure (R)-(+)-4-hydroxydodecanoic acid and (S)-(?)-4-hydroxydodecanoic acid were obtained via: (1) synthesis of its diastereomeric esters of (R,S)-4-hydroxydodecanoic (R)-(?)-2-phenylpropionate; (2) separation of diastereomers via preparative HPLC, and (3) subsequent hydrolysis of the obtained optical pure ester of (R)-(+)-4-hydroxydodecanoic acid (R)-(?)-2-phenylpropionate and (R)-(?)-4-hydroxydodecanoic acid (R)-(?)-2-phenylpropionate, respectively. Further assays of NK cells activation using each enantiomer showed that only the (R)-(+)-4-hydroxydodecanoic acid can activate NK cells. 相似文献
18.
Feeding experiments in cupric chloride-treated Pisum sativum pods and seedlings have demonstrated the preferential incorporation of (+)-(6aS,11aS)-[3H]maackiain over (?)-(6aR, 11aR)-[14C]maackiain into (+)-(6aR, 11aR)-pisatin, establishing that the 6a-hydroxylation of pterocarpans proceeds with retention of configuration. (+)- (6aR,11aR)-6a-hydroxymaackiain was similarly incorporated much better than (?)-(6aS,11aS)-6a- hydroxymaackiain. Where (?)-isomers were incorporated, optical activity measurements on the pisatin produced indicated significant synthesis of (?)-pisatin as well as the normal (+)-pisatin. 7,2′-Dihydroxy-4′,5′- methylenedioxyisoflav-3-ene and both enantiomers of 7,2′-dihydroxy-4′,5′-methylenedioxyisoflavan were poor precursors of pisatin. 相似文献
19.
H.J. Zeringue 《Phytochemistry》1984,23(11):2501-2503
(?)-Cryptocaryalactone (6-[2-acetoxy-4-phenyl-3-butenyl]-5,6-dihydro-2-pyranone) and (?)-deacetylcryptocaryalactone (6-[2-hydroxy-4-phenyl-3-butenyl]-5,6-dihydro-2-pyranone) isolated from Cryptocarya moschata seeds are natural germination inhibitors. Applied at 0.004 M, the second compound completely arrested germination of velvetleaf (Abutilon theophrasti) and decreased the germination rate of soybeans, but did not appear to affect corn. The first compound was not as effective; 0.004 M reduced velvetleaf germination 50%. 相似文献
20.
Koichi Koshimizu Satoshi Matsubara Toshiatsu Kusaki Tetsuo Mitsui 《Bioscience, biotechnology, and biochemistry》2013,77(7):795-801
A new cytokinin was isolated from methanol extracts of immature lupin seeds (Lupinus luteus) through successive purification of charcoal adsorptions, silver precipitations, ion exchange and paper chromatography. The structure was confirmed by spectral data and synthesis as (?)-6-N-(4-hydroxy-3-methylbutylamino)purine, (?)-dihydrozeatin (I). 相似文献