Use of free air as oxidant and copper（II）chloride as catalyst,3,3＇-di-tert-butylbi-phenyl-2,5,2＇,5＇-diquinone（BBDQ）was prepared via catalytic oxidation of 2,2＇-dihydroxy-3,3＇-di-tert-butyl-5,5＇-dimethoxy-bip...Use of free air as oxidant and copper（II）chloride as catalyst,3,3＇-di-tert-butylbi-phenyl-2,5,2＇,5＇-diquinone（BBDQ）was prepared via catalytic oxidation of 2,2＇-dihydroxy-3,3＇-di-tert-butyl-5,5＇-dimethoxy-biphenyl（di-BHA）.The yield of reaction attained 95% and the selectivity for BBDQ was 100%.The single-crystal X-ray diffraction analysis reveals that the dihedral angle between two rings（benzene rings for di-BHA and quinone rings for BBDQ）changes from 89.8 to 45.3o,indicating the steric hindrance effects of methyl disappear in the oxidation process.The crystal structures of di-BHA and BBDQ are further confirmed by their spectral characterizations.The probable mechanism for this oxidation process is also discussed.展开更多
A new complex[Mn(DHTA)(bipy)0.5]n(1,H2DHTA=2,5-dihydroxy-1,4-benzenedicarboxylic acid,bipy=2,2΄-bipyridine)was hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,single-crystal...A new complex[Mn(DHTA)(bipy)0.5]n(1,H2DHTA=2,5-dihydroxy-1,4-benzenedicarboxylic acid,bipy=2,2΄-bipyridine)was hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,single-crystal and power X-ray diffraction.It belongs to monoclinic system,C2/c space group with a=12.874(13),b=11.302(12),c=17.352(18)Å,β=101.574(15)°,V=2474(4)Å3 and Z=4.It displays a one-dimensional zigzag chain-like structure,which was further extended into a three-dimensional supramolecular structure by hydrogen bonds andπ-πinteractions.Moreover,we analyzed Natural Bond Orbital(NBO)of 1 in using the PBE0/LANL2DZ method built in Gaussian 03 Program.The calculation results show the obvious covalent interaction between the coordinated atoms and Mn(Ⅱ)ion.展开更多
A new chromone derivative, 3-[1- (2, 4, 6-trihydroxyphenyl) 3-di-(4-hydroxyphenyl) 1-propanone-2-yl] 5,7-dihydroxy-8-di(4-hydroxyphenyl)methyl-4H-1-benzopyran-4-one, named as isomohsenone was isolated from the roots o...A new chromone derivative, 3-[1- (2, 4, 6-trihydroxyphenyl) 3-di-(4-hydroxyphenyl) 1-propanone-2-yl] 5,7-dihydroxy-8-di(4-hydroxyphenyl)methyl-4H-1-benzopyran-4-one, named as isomohsenone was isolated from the roots of Stellera chamaejasme L. together with known chamaechromone. Its structure was determined by the analysis of MS and NMR data, especially 2D NMR spectra.展开更多
Two new compounds 7-hydroxy-5-O-（β-D-glucopyranoside） flavan （1） and （Z）-4＇,6＇-dihydroxy-2＇-O-（β-D-glucopyranoside） chalcone （2）, along with eight known compounds, were isolated from the stem bark of Dr...Two new compounds 7-hydroxy-5-O-（β-D-glucopyranoside） flavan （1） and （Z）-4＇,6＇-dihydroxy-2＇-O-（β-D-glucopyranoside） chalcone （2）, along with eight known compounds, were isolated from the stem bark of Drypetes parvifolia （Euphorbiaceae）. Their structures were established on the basis of spectroscopic analysis and chemical evidence.展开更多
A new flavone glycoside, 5,8-dihydroxy-4',6,7-trimethoxyflavone 8-O-(-D-glucopyranoside 1, together with three known flavonoids, pedalitin 2, cirsimartin 3 and genkwanin 4, were isolated from the aerial parts of I...A new flavone glycoside, 5,8-dihydroxy-4',6,7-trimethoxyflavone 8-O-(-D-glucopyranoside 1, together with three known flavonoids, pedalitin 2, cirsimartin 3 and genkwanin 4, were isolated from the aerial parts of Isodon enanderianus. Their structures were determined on the basis of spectral data.展开更多
The present work deals with the research of chemical constituents and evaluation of antioxidant properties of Bebotho propolis. From the ethyl acetate extract, we isolated, using various chromatographic techniques, a ...The present work deals with the research of chemical constituents and evaluation of antioxidant properties of Bebotho propolis. From the ethyl acetate extract, we isolated, using various chromatographic techniques, a mixture of two identical compounds (isomers) indexed PBy4a and PByb. The structures of these compounds were elucidated by means of spectroscopic analysis techniques (MS, IR, <sup>1</sup>H-NMR, <sup>13</sup>C-NMR, HMBC and HSQC) and by comparison of the spectral data with those described in the literature. Thus, these compounds were identified to a mixture of two chromones namely 5,7-dihydroxy-2-methylchromone-6-C-α-D-glucopyranoside and 5,7-dihydroxy-2-methylchromone-8-C-β-D-glucopyranoside, first reported in propolis. The study of the antiradical power, chelating power and the quantification of phenolic compound of these same extracts, showed interesting properties that propolis extracts have to scavenge free radicals.展开更多
A new flavonoid glycoside, 5, 7-dihydroxy-4'-methoxyflavonoid 7-Q-[6-O-(4-O-acetyl-alpha-L-rhamnosyl)-3-O-beta-D-glucosyl]-6-O-acetyl-beta-D-glucoside was isolated from Thalictrum przewalskii. Its structure was de...A new flavonoid glycoside, 5, 7-dihydroxy-4'-methoxyflavonoid 7-Q-[6-O-(4-O-acetyl-alpha-L-rhamnosyl)-3-O-beta-D-glucosyl]-6-O-acetyl-beta-D-glucoside was isolated from Thalictrum przewalskii. Its structure was determined on basis of spectroscopic evidences.展开更多
Two hydrates of sodium 5,7-dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate ([Na(H2O)](C17H13O6SO3)2H2O, 1) and nickel 5,7-dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate ([Ni(H2O)6](C17H13O6SO3)24H2O, ...Two hydrates of sodium 5,7-dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate ([Na(H2O)](C17H13O6SO3)2H2O, 1) and nickel 5,7-dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate ([Ni(H2O)6](C17H13O6SO3)24H2O, 2) were syn-thesized and characterized by IR, 1H NMR and X-ray diffraction analyses. The hydrate 1 crystallizes in the mono-clinic system, space group P2(1) with a=0.8201(9) nm, b=0.8030(8) nm, c=1.5361(16) nm, =102.052(12), V=0.9893(18) nm3, Dc=1.579 g/cm3, Z=2, =0.252 nm-1, F(000)=488, R=0.0353, wR=0.0873. The hydrate 2 belongs to triclinic system, space group P-1 with a=0.7411(3) nm, b=0.8333(3) nm, c=1.7448(7) nm, a=86.361(6), 撸?6.389(5), ?=88.999(3), V=1.0731(7) nm3, Dc=1.587 g/cm3, Z=1, =0.649 mm-1, F(000)=534. In the structure of 1, the sodium cation is coordinated by six oxygen atoms and two adjacent ones are bridged by three oxygen atoms to form an octahedron chain. The C—H…p hydrogen bonds exist between two isoflavone molecules in the structure of 2. Meanwhile, hydrogen bonds in two compounds, link themselves to assemble two three-dimensional network structures, respectively.展开更多
基金supported by the 973 Program (2005CB623607)the National Natural Science Foundation of China (No.20771061)the scientific program 2008BAE64B09
文摘Use of free air as oxidant and copper（II）chloride as catalyst,3,3＇-di-tert-butylbi-phenyl-2,5,2＇,5＇-diquinone（BBDQ）was prepared via catalytic oxidation of 2,2＇-dihydroxy-3,3＇-di-tert-butyl-5,5＇-dimethoxy-biphenyl（di-BHA）.The yield of reaction attained 95% and the selectivity for BBDQ was 100%.The single-crystal X-ray diffraction analysis reveals that the dihedral angle between two rings（benzene rings for di-BHA and quinone rings for BBDQ）changes from 89.8 to 45.3o,indicating the steric hindrance effects of methyl disappear in the oxidation process.The crystal structures of di-BHA and BBDQ are further confirmed by their spectral characterizations.The probable mechanism for this oxidation process is also discussed.
基金supported by the Science and Technology development plan of Jilin Province(2015052006JH)。
文摘A new complex[Mn(DHTA)(bipy)0.5]n(1,H2DHTA=2,5-dihydroxy-1,4-benzenedicarboxylic acid,bipy=2,2΄-bipyridine)was hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,single-crystal and power X-ray diffraction.It belongs to monoclinic system,C2/c space group with a=12.874(13),b=11.302(12),c=17.352(18)Å,β=101.574(15)°,V=2474(4)Å3 and Z=4.It displays a one-dimensional zigzag chain-like structure,which was further extended into a three-dimensional supramolecular structure by hydrogen bonds andπ-πinteractions.Moreover,we analyzed Natural Bond Orbital(NBO)of 1 in using the PBE0/LANL2DZ method built in Gaussian 03 Program.The calculation results show the obvious covalent interaction between the coordinated atoms and Mn(Ⅱ)ion.
文摘A new chromone derivative, 3-[1- (2, 4, 6-trihydroxyphenyl) 3-di-(4-hydroxyphenyl) 1-propanone-2-yl] 5,7-dihydroxy-8-di(4-hydroxyphenyl)methyl-4H-1-benzopyran-4-one, named as isomohsenone was isolated from the roots of Stellera chamaejasme L. together with known chamaechromone. Its structure was determined by the analysis of MS and NMR data, especially 2D NMR spectra.
基金One of the authors(J.Wandji)is grateful for grant(No.F/2624-3F)from the International Foundation for Science(Sweden)the sponsorship of the"UniversitéParis Descartes,France"during his multiple research visits in Paris.
文摘Two new compounds 7-hydroxy-5-O-（β-D-glucopyranoside） flavan （1） and （Z）-4＇,6＇-dihydroxy-2＇-O-（β-D-glucopyranoside） chalcone （2）, along with eight known compounds, were isolated from the stem bark of Drypetes parvifolia （Euphorbiaceae）. Their structures were established on the basis of spectroscopic analysis and chemical evidence.
文摘A new flavone glycoside, 5,8-dihydroxy-4',6,7-trimethoxyflavone 8-O-(-D-glucopyranoside 1, together with three known flavonoids, pedalitin 2, cirsimartin 3 and genkwanin 4, were isolated from the aerial parts of Isodon enanderianus. Their structures were determined on the basis of spectral data.
文摘The present work deals with the research of chemical constituents and evaluation of antioxidant properties of Bebotho propolis. From the ethyl acetate extract, we isolated, using various chromatographic techniques, a mixture of two identical compounds (isomers) indexed PBy4a and PByb. The structures of these compounds were elucidated by means of spectroscopic analysis techniques (MS, IR, <sup>1</sup>H-NMR, <sup>13</sup>C-NMR, HMBC and HSQC) and by comparison of the spectral data with those described in the literature. Thus, these compounds were identified to a mixture of two chromones namely 5,7-dihydroxy-2-methylchromone-6-C-α-D-glucopyranoside and 5,7-dihydroxy-2-methylchromone-8-C-β-D-glucopyranoside, first reported in propolis. The study of the antiradical power, chelating power and the quantification of phenolic compound of these same extracts, showed interesting properties that propolis extracts have to scavenge free radicals.
文摘A new flavonoid glycoside, 5, 7-dihydroxy-4'-methoxyflavonoid 7-Q-[6-O-(4-O-acetyl-alpha-L-rhamnosyl)-3-O-beta-D-glucosyl]-6-O-acetyl-beta-D-glucoside was isolated from Thalictrum przewalskii. Its structure was determined on basis of spectroscopic evidences.
基金the Natural Science Foundation of Shaanxi Province (No. 2001K11-G5).
文摘Two hydrates of sodium 5,7-dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate ([Na(H2O)](C17H13O6SO3)2H2O, 1) and nickel 5,7-dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate ([Ni(H2O)6](C17H13O6SO3)24H2O, 2) were syn-thesized and characterized by IR, 1H NMR and X-ray diffraction analyses. The hydrate 1 crystallizes in the mono-clinic system, space group P2(1) with a=0.8201(9) nm, b=0.8030(8) nm, c=1.5361(16) nm, =102.052(12), V=0.9893(18) nm3, Dc=1.579 g/cm3, Z=2, =0.252 nm-1, F(000)=488, R=0.0353, wR=0.0873. The hydrate 2 belongs to triclinic system, space group P-1 with a=0.7411(3) nm, b=0.8333(3) nm, c=1.7448(7) nm, a=86.361(6), 撸?6.389(5), ?=88.999(3), V=1.0731(7) nm3, Dc=1.587 g/cm3, Z=1, =0.649 mm-1, F(000)=534. In the structure of 1, the sodium cation is coordinated by six oxygen atoms and two adjacent ones are bridged by three oxygen atoms to form an octahedron chain. The C—H…p hydrogen bonds exist between two isoflavone molecules in the structure of 2. Meanwhile, hydrogen bonds in two compounds, link themselves to assemble two three-dimensional network structures, respectively.
基金supported financially by the NSFC(Nos. 30830115 and 20902093)the foundation of State Key Laboratory of Phytochemistry and Plant Resources in West China(No.P2008- ZZ13)the Reservation-talent Project of Yunnan Province(No. 2011 CI043)
文摘Received 22 November 2012 Received in revised form 25 December 2012 Accepted 2B December 2012 Available online 4 February 2013
