共查询到20条相似文献,搜索用时 31 毫秒
1.
O. V. Ardashov A. M. Genaev I. V. Il’ina D. V. Korchagina K. P. Volcho N. F. Salakhutdinov 《Russian Journal of Organic Chemistry》2010,46(12):1786-1789
Hydrogenation of (1R,2R,6S)-3-methyl-6-(1-methylethenyl)cyclohex-3-ene-1,2-diol was studied. Nickel chloride-sodium tetrahydridoborate system turned
out to selectively reduce the double bond in the isopropenyl group. The results of conformational analysis of (1R,2R,6S)-3-methyl-6-(1-methylethenyl)cyclohex-3-ene-1,2-diol and its partly and completely hydrogenated derivatives were in a good
agreement with the NMR data. 相似文献
2.
1,2-Epoxycarotenoids: Synthesis, 1H-NMR and CD Studies of (S)-1,2-Epoxy-1,2-dihydrolycopene and (S)-1′,2′-Epoxy-1′, 2′ -dihydro-γ-carotene The synthesis of (S)-1,2-epoxy-1,2-dihydrolycopene ((S)- 1 ) and (S)-1′, 2′ -epoxy- 1′, 2′ -dihydro-γ-carotene ((S)- 2 ) are described. The CD spectra of the (all-E)-isomers and of the isomers (7Z, S)- 1 and (7′Z, S)- 2 are discussed. The comparison of the CD spectra of the synthetic (S)- 1 and the compound isolated from the tomatoes proves the (S)-configuration of the natural product. 相似文献
3.
Frdric Schaller Jean‐Luc Wolfender Kurt Hostettmann Steven Mavi 《Helvetica chimica acta》2001,84(1):222-229
Two new `quinone methide' diterpenes with a cassane skeleton were isolated from the root bark of Bobgunnia madagascariensis (Desv. ) J. H. Kirkbr. & Wiersema (Leguminosae). The two compounds occurred as a diastereoisomer mixture 1 / 2 . Their structure was established as (4R,6aS,10aS)‐ and (4S,6aS,10aS)‐ 1,4,6a,7,8,9,10,10a‐octahydro‐4,11‐dihydroxy‐7,7,10a‐trimethyl‐2H‐phenanthro[1,2‐c]pyran‐6,12‐dione by spectroscopic methods and by comparison with the data obtained for another `quinone methide' diterpene isolated previously from the same plant and identified by single‐crystal X‐ray analysis. 1H‐ and 13C‐NMR signals were assigned by extensive in‐mixture 2D correlation experiments, and 1H‐NMR spectra of the separated diastereoisomers 1 and 2 were recorded by on‐flow LC/NMR. The interconversion of 1 and 2 was followed by repeated stop‐flow LC/NMR experiments over a two‐hour period. Compounds 1 and 2 showed moderate antifungal properties towards human pathogenic fungi, in particular the yeast Candida albicans. 相似文献
4.
Nan Zhao Guo‐Chun Yang Da‐Hong Li Xin‐Yu Li Zhan‐Lin Li Jiao Bai Xiao‐Qiu Liu Hui‐Ming Hua 《Helvetica chimica acta》2015,98(9):1332-1336
Two new sesquiterpenes, named 9‐methoxymyrrhone ( 1 ) and rel‐(1S,2S,3R,4S)‐1,2‐epoxy‐3‐methoxyfuranogermacr‐10(15)‐en‐6‐one ( 2 ), together with nine known compounds ( 3 – 11 ), were isolated from the resin of Commiphora opobalsamum. The structures were established by HR‐ESI‐MS, 1D‐, and 2D‐NMR spectroscopic analyses. 相似文献
5.
Bryan N.S. Pinto Milena G. Teixeira Elson S. Alvarenga 《Magnetic resonance in chemistry : MRC》2020,58(6):559-565
Phtalides are secondary metabolites found in several fungi with a wide range of biological activities. A novel phthalide analog was synthesized by Diels–Alder reaction between cyclopentadiene and 3,4-dichlorofuran-2(5H)-one. Quantum mechanical calculations were used in conjunction with the spectrometric methods to determine the structure of the title compound. The calculated NMR chemical shifts for eight candidate pairs of enantiomers were compared with the experimental NMR chemical shifts applying the DP4 probability and mean absolute errors methodology. DP4 analysis using 1H and 13C NMR chemical shifts without assignment of the signals presented 100% probability for the correct candidate structure 3d , proving the consistency of the method even without spectra interpretation. Results from theoretical calculation and NMR spectra interpretation were in agreement to the structure of rac-(3aR,4S,4aS,5R,8S,8aR,9R,9aS)-3a,9a-dichloro-3a,4,4a,5,8,8a,9,9a-octahydro-4,9:5,8-dimethanonaphtho[2,3-c]furan-1(3H)-one. 相似文献
6.
Preparative synthesis of the Corey chiral controller for enantioselective dihydroxylation of olefins
A five-step synthesis of both enantiomers of 1,2-di(2,4,6-trimethylbenzylamino)-1,2-diphenylethane,i.e., Corey (R,R)- and (S,S)-controllers for enantioselective dihydroxylation of olefins by osmium tetroxide, starting from α,α′-diphenylglyoxime, has
been developed. The key operations in the synthesis are the optical resolution of intermediaterac-1,2-diamino-1,2-diphenylethane into two enantiomers using only (R,R)-tartaric acid and the subsequent enhancement of the enantiomeric purity to >98% by crystallizations of the corresponding
Schiff's bis-bases. Analysis of the enantiomeric purity of the controllers can be easily performed using1H NMR spectra of their salts with (R)-α-methoxy-α-(trifluoromethyl)phenylacetic acid (MosherR-acid).
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 101–105, January, 1997. 相似文献
7.
J. Couquelet M. Madesclaire F. Leal V. P. Zaitsev S. Kh. Sharipova 《Chemistry of Heterocyclic Compounds》2001,37(7):898-902
The reaction of (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with glutaraldehyde has been studied. It has been established on the basis of AM1 and PM3 calculations and 1H NMR spectra recorded in the presence of the shift reagent Eu(fod)3 that (1S,3S,4S,7R,11R)-3-(4-nitrophenyl)-11-aza-2,6-dioxatricyclo[5,3,1,04,11]undecane is formed as the result of the reaction. 相似文献
8.
Z-α-N-methylacetamidocinnamic acid and its methyl ester were hydrogenated with rhodhim(I) complexes containing (2R, 3R)-O-2,3-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane (DIOP) or its carbocyclic analogues: (1R,2R)-trans-1,2-bis(diphenylphosphinomethyl)cyclobutane or (1S,2S)-trans-1,2-bis(diphenylphosphinomethyl) cyclohexane. The N-acetyl-N-methylphenylalanine methyl ester reaction product was formed with an optical purity of 73% ee-(R) [(2R, 3R)-DIOP]; 43% ee-(R) [(1R, 2R)-cyclobutane analogue]; and 26% ee-(R) [(1S,2S])-cyclohexane analogue]. Similarly, N-acetyl-N-methylphenylalanine was formed with an optical purity of 87% ee-R [(2R, 3R)-DIOP] and 68% ee-(R) [(1R, 2R)-cyclobutane analogue]. 相似文献
9.
Maciej Dawidowski Franciszek Herold Marcin Wilczek Jerzy Kleps Irena Wolska Jadwiga Turo Andrzej Chodkowski Pawe Widomski Anna Bielejewska 《Tetrahedron: Asymmetry》2009,20(15):1759-1766
The synthesis, chemical properties, and conformational analysis of enantiopure (4R,9aS)-, (4S,9aR)-, (4S,9aS)-, and (4R,9aR)-4-phenyl-perhydropyrido[1,2-a]pyrazine-1,3-diones having potential biological activity are described. An interesting example of the coexistence of two invertomers of the (4R,9aR)-diastereomer in a single crystal unit cell is reported. The invertomers differ in the cis/trans-relationship between the fused rings and in the absolute configuration at the chiral nitrogen atom. The structure and equilibrium distributions of the respective conformers have been determined by NMR spectroscopy in both polar and non-polar solvents at various temperatures. The NMR spectra show that dynamic processes in the imide parts of the interconverting species are restrained by self-aggregation. The (4S,9aR)-diastereomer exists in a single conformation with insignificant dynamic effects. 相似文献
10.
Giuseppe Impellizzeri Franca D’Alessandro Giuseppe Pappalardo Corrado Tringali 《Journal of inclusion phenomena and macrocyclic chemistry》2005,51(3-4):173-180
The condensation reaction of 6-deoxy-6-amino(2-aminoethyl)-cyclomaltoheptaose (β-CyDen) and racemic [(R, S)-2-(6-methoxy-2-naphthyl) propanoic acid] (R,S-naproxen) affords two new diastereoisomeric naproxen-appended β-cyclodextrin derivatives. The structural analysis of these two β-CyD derivatives, undertaken by combined use of circular dichroism (CD) and 1D or 2D NMR techniques, shows that the naphthalene ring of the naproxen is included in the CyD cavity in both derivatives. The CD spectra are consistent with an axial complexation model, moreover, the self-inclusion mode is further corroborated by 1H NMR ROESY spectra which also suggest the orientation of the naphthyl moiety in the cavity of both the diastereoisomers. 相似文献
11.
New Chiral and Achiral Imines and Bisimines Derived from 2‐Phenyl‐1H‐imidazole‐4‐carbaldehyde. Synthesis,Structural Studies and Complexation Stability Constants
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Synthesis and properties of new imines and bisimines derived from 2‐phenyl‐1H‐imidazole‐4‐carbaldehyde and amines/diamines were studied. (2‐Phenyl‐1H‐imidazole‐4‐yl)methanol was oxidized to 2‐phenyl‐1H‐imidazole‐4‐carbaldehyde with better yield 55% by the modification of literature procedure. This aldehyde was condensed with the following achiral and chiral amines or 1,2‐diamines: ethanamine, propan‐1‐amine, butan‐1‐amine, 2‐methylpropan‐1‐amine, cyclohexanamine, (2R)‐ and (2S)‐3‐methylbutan‐2‐amine, (1R)‐ and (1S)‐1‐cyclohexylethanamine, (S)‐1‐aminopropan‐2‐ol, (S)‐1‐(2‐phenyl‐1H‐imidazol‐4‐yl)ethanamine, (S)‐1‐(2‐phenyl‐1H‐imidazol‐4‐yl)‐2‐methylpropan‐1‐amine, (S)‐1‐(2‐phenyl‐1H‐imidazol‐4‐yl)‐3‐methylbutan‐1‐amine, ethane‐1,2‐diamine, and (1R,2R)‐ and (1S,2S)‐cyclohexane‐1,2‐diamine. Sixteen condensation products, especially chiral imines and bisimines, were prepared by founded procedures in 45–99% of yields and characterized by the 1H NMR spectroscopy in solution, mass spectrometry, and elemental analyses. The optical rotation values in the case of chiral ones were also observed. Stability constants of Cu(II) complexes of selected prepared imines/bisimines were determined. 相似文献
12.
Tribenzotriquinacene Receptors for C60 Fullerene Rotors: Towards C3 Symmetrical Chiral Stators for Unidirectionally Operating Nanoratchets
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Dr. Björn Bredenkötter Dr. Maciej Grzywa Dr. Mohammad Alaghemandi Dr. Rochus Schmid Prof. Dr. Wouter Herrebout Prof. Dr. Patrick Bultinck Prof. Dr. Dirk Volkmer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(29):9100-9110
The synthesis of a stereochemically pure concave tribenzotriquinacene receptor ( 7 ) for C60 fullerene, possessing C3 point group symmetry, by threefold condensation of C2‐symmetric 1,2‐diketone synthons ( 5 ) and a hexaaminotribenzotriquinacene core ( 6 ) is described. The chiral diketone was synthesized in a five‐step reaction sequence starting from C2h‐symmetric 2,6‐di‐tert‐butylanthracene. The highly diastereo‐discriminating Diels–Alder reaction of 2,6‐di‐tert‐butylanthracene with fumaric acid di(?)menthyl ester, catalyzed by aluminium chloride, is the relevant stereochemistry introducing step. The structure of the fullerene receptor was verified by 1H and 13C NMR spectroscopy, mass spectrometry and single crystal X‐ray diffraction. VCD and ECD spectra were recorded, which were corroborated by ab initio DFT calculations, establishing the chiral nature of 7 with about 99.7 % ee, based on the ee (99.9 %) of the chiral synthon ( 1 ). The absolute configuration of 7 could thus be established as all‐S [(2S,7S,16S,21S,30S,35S)‐( 7 )]. Spectroscopic titration experiments reveal that the host forms 1:1 complexes with either pure fullerene (C60) or fullerene derivatives, such as rotor 1′‐(4‐nitrophenyl)‐3′‐(4‐N,N‐dimethylaminophenyl)‐pyrazolino[4′,5′:1,2][60]fullerene ( R ). The complex stability constants of the complexes dissolved in CHCl3/CS2 (1:1 vol. %) are K([ C60 ? 7 ])=319(±156) M ?1 and K([ R ? 7 ])=110(±50) M ?1. With molecular dynamics simulations using a first‐principles parameterized force field the asymmetry of the rotational potential for [ R ? 7 ] was shown, demonstrating the potential suitability of receptor 7 to act as a stator in a unidirectionally operating nanoratchet. 相似文献
13.
Luk'yanenko N. G. Lobach A. V. Leus O. N. 《Russian Journal of Organic Chemistry》2003,39(7):1042-1047
New chiral diaza crown ethers with exocyclic hydroxy groups were synthesized by reactions of (2S,3S)-1,4-dibenzyloxy-2,3-bis(2-oxiranylmethoxy)butane with N,N'-dibenzyl-1,2-ethanediamine and (4S,5S)-4,5-bis(benzylaminomethyl)-2,2-dimethyl-1,3-dioxolane. Catalytic debenzylation of the products gave the corresponding derivatives having secondary amino groups. The obtained diaza crown ethers, as well as some known crown ethers, were used as asymmetric catalysts in the reduction of pinacolone and acetophenone with sodium tetrahydridoborate in methylene chloride. Depending on the catalyst structure, the optical yield of the reduction products ranged from 5 to 90%. 相似文献
14.
Suleimenov E. M. Raldugin V. A. Shakirov M. M. Bagryanskaya I. Yu. Gatilov Yu. V. Kulyjiasov A. T. Adekenov S. M. 《Russian Chemical Bulletin》2003,52(5):1210-1212
Oxidation of (+)-sabinol, (1S,3R,5S)-1-isopropyl-4-methylidenebicyclo[3.1.0]hexan-3-ol, by active MnO2 afforded not the expected sabinone but only its [4+2]-cyclodimer. The molecular structure of the latter was established by X-ray diffraction analysis. The 1H and 13C NMR spectra of this cyclodimer were interpreted using 2D NMR spectroscopy. 相似文献
15.
Starting from shikimic acid, the total synthesis of zeylenone was studied. The product was proved to be the (+)antipode of zeylenone through analysis and comparison of their respective spectra (including NMR, MS, IR and CD) and optical data. The absolute configuration of the natural product was thus determined to be (1S,2S,3R). 相似文献
16.
Reinhard Benn 《Magnetic resonance in chemistry : MRC》1983,21(1):60-63
The 13C and 1H NMR spectra of (–)-bis[1R, 3 R, 4S]menthylphosphine (1) are assigned by two-dimensional double quantum NMR and 13C? 1H shift correlation diagrams. The variable temperature spectra of 1 indicate hindered rotation about the P? C bonds. 相似文献
17.
1,2-Epoxycarotenoids, Synthesis of (S)-1,2-Epoxy-1,7,8,7′,8′-hexahydro-Ψ, Ψ-carotene ((S)-1,2-Epoxy-1,2-dihydro-ζ-carotene) The synthesis of (S)-1,2-Epoxy-1,2-dihydro-ζ-carotene ((all-E,S)- 1 ) using (E,E)-farnesol (3) as starting material, and a Sharpless epoxidation as key step is described. 相似文献
18.
New Route to Stabilize Ruthenium Nanoparticles with Non‐Isolable Chiral N‐Heterocyclic Carbenes
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Dr. Luis Miguel Martínez‐Prieto Dr. Angélique Ferry Dr. Patricia Lara Dr. Christian Richter Dr. Karine Philippot Prof. Frank Glorius Dr. Bruno Chaudret 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17495-17502
Ru nanoparticles (RuNPs) stabilized by non‐isolable chiral N‐heterocyclic carbenes (NHCs), namely SIDPhNp ((4S,5S)‐1,3‐di(naphthalen‐1‐yl)‐4,5‐diphenylimidazolidine) and SIPhOH ((S)‐3‐((1S,2R)‐2‐hydroxy‐1,2‐diphenylethyl)‐1‐((R)‐2‐hydroxy‐1,2‐diphenylethyl)‐4,5‐dihydro‐3H‐imidazoline), have been synthesized through a new procedure that does not require isolation of the free carbenes. The obtained RuNPs have been characterized by state‐of‐the‐art techniques and their surface chemistry has been investigated by FTIR and solid‐state MAS NMR upon the coordination of CO, which indicated the presence of free and reactive Ru sites. Their catalytic activity has been tested in various hydrogenation reactions involving competition between different sites, whereby interesting differences in selectivity were observed, but no enantioselectivity. 相似文献
19.
Antioxidant activity guided fractionation of extracts of the aerial parts of the title plant and HPLC separation yielded a series of oxygenated long-chain alkylcatechols. Their structures were inferred by spectroscopic methods and chemical transformations to be the novel 4-[(2S,4R,6S)-4-(acetyloxy)tetrahydro-6-pentyl-2H-pyran-2-yl]benzene-1,2diol ( 1a ), 4-[(2S,4R6S)-tetrahydro-4-hydroxy-6-pentyl-2H-pyran-2-yl]benzene-1,2-diol ( 1b ), 4-[(3S,5S)-5-(acetyloxy)-3-hydroxydecyl]benzene-1,2-diol (2a), 4-[(3S,5S)3-(acetyloxy)-5-hydroxydecyl]benzene-1,2-diol ( 2b ), (3S,13Z)-1-(3,4-dihydroxyphenyl)-3-hydroxydocos-13-en-5-one ( 3a ), (Z)-1-(3,4-dihydroxyphenyl)docos-13-en-5-one ( 4 ), besides the known l-(3,4-dihydroxyphenyl)icosan-5-one ( 5 ). The absolute configurations of the optically active compounds which are structurally related to the [n]-gingerols ( 6 ) and -diols ( 7 ) were established by the high-field 1H-NMR application of Mosher's method. All compounds are in vitro potent antioxidants, inhibiting the Fe2+-catalysed autoxidation of linoleic acid in the same order of magnitude as the commercial antioxidant 2,6-di(tert-butyl)-4-methylphenol (BHT). The dose-dependent inhibitory effects on soybean-lipoxygenase are in the μmol range, that of the most effective compound ( 3a ) in the nmol range, hence being significantly more potent than the Known anti-inflammatory and analgesic drugs indomethacin and nordihydroguaiaretic acid. 相似文献
20.
Two new alkaloids, i.e., (2,3‐dihydro‐1‐oxo‐1H‐pyrrolo[1,2‐a]pyrrol‐7‐yl)methyl (2S*,3S*)‐3‐[(β‐D ‐glucopyranosyl)oxy]‐2‐hydroxy‐2‐(1‐methylethyl)butanoate ( 1 ) and 1,2‐dihydro‐8‐methoxy‐2‐oxoquinoline‐4‐carboxylic acid ( 2 ), were isolated from the alcoholic extract of the whole plant of Cynoglossum gansuense, together with twelve known compounds Their structures were characterized by means of spectroscopic methods, especially by 1H‐, 13C‐, and 2D‐NMR, as well as by HR‐MS experiments and comparison with literature data. 相似文献