共查询到20条相似文献,搜索用时 206 毫秒
1.
Guo‐Fu Chen Chang‐Heng Tan Zhu‐Lian Li Shan‐Hao Jiang Da‐Yuan Zhu 《Helvetica chimica acta》2003,86(3):787-792
Pseudolarolides O ( 1 ) and P ( 2 ), two novel triterpenoids with a cycloartane‐type framework, were isolated from the seeds of Pseudolarix kaempferi Gord. (Pinaceae). Their structures were elucidated as (16R,23S,25R)‐16,23‐epoxy‐3,4 : 9,10‐disecocycloartan‐1(10),9(11)‐diene‐3(4),26(23)‐diolide ( 1 ), and (9S,16R,23S,25R)‐1,9 : 16,23‐diepoxy‐8,9 : 9,10‐disecocycloartan‐1(29),5(6),10(19)‐triene‐3(4),26(23)‐diolide ( 2 ), respectively, on the basis of spectroscopic techniques and X‐ray‐diffraction studies. 相似文献
2.
Pnar Akbay Jürg Gertsch Ihsan als Jrg Heilmann Oliver Zerbe Otto Sticher 《Helvetica chimica acta》2002,85(7):1930-1942
Two novel and three new sterol glycosides were isolated from the MeOH extract of the aerial parts of Ajuga salicifolia (L.) Schreber . The structures of the compounds were elucidated as (3R,16S,17S,20R,22S,23S, 24S,25S)‐16,23 : 16,27 : 22,25‐triepoxy‐3‐(β‐D ‐glucopyranosyloxy)coprostigmast‐7‐en‐17‐ol ( 1 ), (3R,16S,17S, 20R,22S,23S,24S,25S)‐16,23 : 16,27 : 22,25‐triepoxy‐3‐{[β‐D ‐glucopyranosyl‐(1→2)‐β‐D ‐glucopyranosyl]oxy}coprostigmast‐7‐en‐17‐ol ( 2 ), (3R,16S,17R,20S,22R,24S,25S)‐22,25‐epoxy‐3,27‐bis(β‐D ‐glucopyranosyloxy)coprostigmast‐7‐en‐16‐ol ( 3 ), (3R,16S,17R,20S,22R,24S,25S)‐22,25‐epoxy‐3‐{[β‐D ‐glucopyranosyl‐(1→2)‐β‐D ‐glucopyranosyl]oxy}‐27‐(β‐D ‐glucopyranosyloxy)coprostigmast‐7‐en‐16‐ol ( 4 ), and (3R,16R,17S,20R,22S,23S, 24S,25S)‐22,25‐epoxy‐3‐(β‐D ‐glucopyranosyloxy)coprostigmast‐7‐ene‐16,17,23,27‐tetrol 27‐acetate ( 5 ) by means of 1D and 2D NMR spectroscopy and HR‐MALDI mass spectrometry. The novel compounds, which consist of three additional ring systems at the coprostigmastane skeleton, were named ajugasalicioside A ( 1 ) and B ( 2 ), and the new compounds C ( 3 ), D ( 4 ) and E ( 5 ). In our cytotoxicity assays (HeLa cells, Jurkat T cells, and peripheral mononuclear blood cells), ajugasaliciosides A–D specifically inhibited the viability and growth of Jurkat T‐leukemia cells at concentrations below 10 μM . Ajugasalicioside A ( 1 ; (IC50=6 μM ) and C ( 3 ; IC50=3 μM ) were the most active compounds. Ajugasalicioside A ( 1 ) induced cell‐cell contact, inhibited Jurkat T cell proliferation, and up‐regulated mRNA levels of the cell‐cycle regulator cyclin D1, which might be an indication for cell differentiation. Furthermore, 1 down‐regulated the mRNA levels of the NF‐κB subunit p65 in a concentration‐dependent manner. These effects were not found for ajugasalicioside B ( 2 ), which has an additional glucose unit, and the onset of cytotoxicity of 2 (IC50=10 μM ) was delayed by 24 h. 相似文献
3.
The isolation and structure elucidation of two new oleanane‐type triterpene glycosides, 29‐(β‐D ‐glucopyranosyloxy)‐2α,3β,23‐trihydroxyolean‐12‐en‐28‐oic acid (=(2α,3β,4α,29α)‐29‐(β‐D ‐glucopyranosyloxy)‐2,3,23‐trihydroxyolean‐12‐en‐28‐oic acid; 1 ) and its C(20)‐epimer, 30‐(β‐D ‐glucopyranosyloxy)‐2α,3β,23‐trihydroxyolean‐12‐en‐28‐oic acid (=(2α,3β,4α,29β)‐29‐β‐D ‐glucopyranosyloxy)‐2,3,23‐trihydroxyolean‐12‐en‐28‐oic acid; 2 ), and a novel nortriterpene glycoside, (17S)‐2α,18β,23‐trihydroxy‐3,19‐dioxo‐19(18→17)‐ abeo‐28‐norolean‐12‐en‐25‐oic acid β‐D ‐glucopyranosyl ester (=(1R,2S,4aS,4bR,6aR,7R,9R,10aS,10bS)‐3,4,4a,4b,5,6,6a,7,8,9,10,10a,10b,11‐tetradecahydro‐1‐hydroxy‐7‐(hydroxymethyl)‐3′,4′,4a,4b,7‐pentamethyl‐2′,8‐ dioxospiro[chrysene‐2(1H),1′‐cyclopentane]‐10a‐carboxylic acid β‐D ‐glucopyranosyl ester; 3 ) from Phlomis viscosa (Lamiaceae) are reported. The structures of the compounds were asigned by means of spectroscopic (IR, 1D‐ and 2D‐NMR, and LC‐ESI‐MS) and chemical (acetylation) methods. 相似文献
4.
Judith C. Gallucci Yukiko Tamura Leo A. Paquette 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(9):o656-o658
In the Diels–Alder reaction, the preferred addition of dienes syn to the O atom in cross‐conjugated cyclohexadienones containing an oxa‐spiro ring system is observed. The two structures reported here, namely rel‐(1R,4aR,9S,9aS,10R)‐4a,9,9a,10‐tetrahydro‐9,10‐diphenylspiro[9,10‐epoxyanthracene‐1(4H),2′‐oxiran]‐4‐one, C27H20O3, and rel‐(1R,4aS,9R,9aS,10S)‐4a,9,9a,10‐tetrahydro‐9,10‐diphenylspiro[9,10‐epoxyanthracene‐1(4H),2′‐oxetane]‐4‐one, C28H22O3, are the minor and sole products, respectively, of the reactions of diphenylisobenzofuran with two slightly different cyclohexadienones. These structures differ in the size of the oxa‐spiro ring, by one C atom, and in the relative configuration at the spirocyclic ring C atom, leading to some minor conformational differences between the two compounds. 相似文献
5.
Biotransformation of (±)‐threo‐7,8‐dihydroxy(7,8‐2H2)tetradecanoic acids (threo‐(7,8‐2H2)‐ 3 ) in Saccharomyces cerevisiae afforded 5,6‐dihydroxy(5,6‐2H2)dodecanoic acids (threo‐(5,6‐2H2)‐ 4 ), which were converted to (5S,6S)‐6‐hydroxy(5,6‐2H2)dodecano‐5‐lactone ((5S,6S)‐(5,6‐2H2)‐ 7 ) with 80% e.e. and (5S,6S)‐5‐hydroxy(5,6‐2H2)dodecano‐6‐lactone ((5S,6S)‐5,6‐2H2)‐ 8 ). Further β‐oxidation of threo‐(5,6‐2H2)‐ 4 yielded 3,4‐dihydroxy(3,4‐2H2)decanoic acids (threo‐(3,4‐2H2)‐ 5 ), which were converted to (3R,4R)‐3‐hydroxy(3,4‐2H2)decano‐4‐lactone ((3R,4R)‐ 9 ) with 44% e.e. and converted to 2H‐labeled decano‐4‐lactones ((4R)‐(3‐2H1)‐ and (4R)‐(2,3‐2H2)‐ 6 ) with 96% e.e. These results were confirmed by experiments in which (±)‐threo‐3,4‐dihydroxy(3,4‐2H2)decanoic acids (threo‐(3,4‐2H2)‐ 5 ) were incubated with yeast. From incubations of methyl (5S,6S)‐ and (5R,6R)‐5,6‐dihydroxy(5,6‐2H2)dodecanoates ((5S,6S)‐ and (5R,6R)‐(5,6‐2H2)‐ 4a ), the (5S,6S)‐enantiomer was identified as the precursor of (4R)‐(3‐2H1)‐ and (2,3‐2H2)‐ 6 ). Therefore, (4R)‐ 6 is synthesized from (3S,4S)‐ 5 by an oxidation/keto acid reduction pathway involving hydrogen transfer from C(4) to C(2). In an analogous experiment, methyl (9S,10S)‐9,10‐dihydroxyoctadecanoate ((9S,10S)‐ 10a ) was metabolized to (3S,4S)‐3,4‐dihydroxydodecanoic acid ((3S,4S)‐ 15 ) and converted to (4R)‐dodecano‐4‐lactone ((4R)‐ 18 ). 相似文献
6.
Tarek Kassem Valrie Rolland Jean Martinez Marc Rolland 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):1037-1039
We present the crystal and molecular structure of two key compounds of a new synthesis strategy for isomers of natural (2S,3R,4S)‐4‐hydroxyisoleucines, 2,3,5,6,7,8‐hexahydro‐3‐(1‐hydroxy‐1‐methyl‐2‐oxopropyl)‐6,8‐methano‐7,7,8a‐trimethyl‐5H‐1,4‐benzoxazin‐2‐one, C16H23NO4, and 2,3,5,6,7,8‐hexahydro‐3‐(1‐methyl‐2‐oxopropyl)‐6,8‐methano‐7,7,8a‐trimethyl‐5H‐1,4‐benzoxazin‐2‐one, C16H23NO3. A new optically pure chiral oxazinone auxiliary derived from (1R,2R,5R)‐2‐hydroxypinan‐3‐one was used. 相似文献
7.
Leif‐A. Garbe Katja Morgenthal Katrin Kuscher Roland Tressl 《Helvetica chimica acta》2008,91(6):993-1007
Epoxides of fatty acids are hydrolyzed by epoxide hydrolases (EHs) into dihydroxy fatty acids which are of particular interest in the mammalian leukotriene pathway. In the present report, the analysis of the configuration of dihydroxy fatty acids via their respective hydroxylactones is described. In addition, the biotransformation of (±)‐erythro‐7,8‐ and ‐3,4‐dihydroxy fatty acids in the yeast Saccharomyces cerevisiae was characterized by GC/EI‐MS analysis. Biotransformation of chemically synthesized (±)‐erythro‐7,8‐dihydroxy(7,8‐2H2)tetradecanoic acid ((±)‐erythro‐ 1 ) in the yeast S. cerevisiae resulted in the formation of 5,6‐dihydroxy(5,6‐2H2)dodecanoic acid ( 6 ), which was lactonized into (5S,6R)‐6‐hydroxy(5,6‐2H2)dodecano‐5‐lactone ((5S,6R)‐ 4 ) with 86% ee and into erythro‐5‐hydroxy(5,6‐2H2)dodecano‐6‐lactone (erythro‐ 8 ). Additionally, the α‐ketols 7‐hydroxy‐8‐oxo(7‐2H1)tetradecanoic acid ( 9a ) and 8‐hydroxy‐7‐oxo(8‐2H1)tetradecanoic acid ( 9b ) were detected as intermediates. Further metabolism of 6 led to 3,4‐dihydroxy(3,4‐2H2)decanoic acid ( 2 ) which was lactonized into 3‐hydroxy(3,4‐2H2)decano‐4‐lactone ( 5 ) with (3R,4S)‐ 5 =88% ee. Chemical synthesis and incubation of (±)‐erythro‐3,4‐dihydroxy(3,4‐2H2)decanoic acid ((±)‐erythro‐ 2 ) in yeast led to (3S,4R)‐ 5 with 10% ee. No decano‐4‐lactone was formed from the precursors 1 or 2 by yeast. The enantiomers (3S,4R)‐ and (3R,4S)‐3,4‐dihydroxy(3‐2H1)nonanoic acid ((3S,4R)‐ and (3R,4S)‐ 3 ) were chemically synthesized and comparably degraded by yeast without formation of nonano‐4‐lactone. The major products of the transformation of (3S,4R)‐ and (3R,4S)‐ 3 were (3S,4R)‐ and (3R,4S)‐3‐hydroxy(3‐2H1)nonano‐4‐lactones ((3S,4R)‐ and (3R,4S)‐ 7 ), respectively. The enantiomers of the hydroxylactones 4, 5 , and 7 were chemically synthesized and their GC‐elution sequence on Lipodex® E chiral phase was determined. 相似文献
8.
Pter Molnr Jzsef Deli Ferenc Zsila Andrea Steck Hanspeter Pfander Gyula Tth 《Helvetica chimica acta》2004,87(1):11-27
Violaxanthin A (=(all‐E,3S,5S,6R,3′S,5′S,6′R)‐5,6 : 5′,6′‐diepoxy‐5,6,5′,6′‐tetrahydro‐β,β‐carotene‐3,3′‐diol =syn,syn‐violaxanthin; 5 ) and violaxanthin B (=(all‐E,3S,5S,6R,3′S,5′R,6′S)‐5,6 : 5′,6′‐diepoxy‐5,6,5′,6′‐tetrahydro‐β,β‐carotene‐3,3′‐diol=syn,anti‐violaxanthin; 6 ) were prepared by epoxidation of zeaxanthin diacetate ( 1 ) with monoperphthalic acid. Violaxanthins 5 and 6 were submitted to thermal isomerization and I2‐catalyzed photoisomerization. The structure of the main products, i.e., (9Z)‐ 5 , (13Z)‐ 5 , (9Z)‐ 6 , (9′Z)‐ 6 , (13Z)‐ 6 , and (13′Z)‐ 6 , was determined by their UV/VIS, CD, 1H‐NMR, 13C‐NMR, and mass spectra. 相似文献
9.
The syntheses of two 2′,3′‐fused bicyclic nucleoside analogues, i.e., 1‐[(4aR,5R,7R,7aS)‐hexahydro‐5‐(hydroxymethyl)‐4,4‐dioxidofuro[3,4‐b][1,4]oxathiin‐7‐yl]pyrimidine‐2,4(1H,3H)‐dione ( 1a ) and 1‐[(4aS,5R,7R,7aS)‐hexahydro‐7‐(hydroxymethyl)‐1,1‐dioxido‐2H‐furo[3,4‐b][1,4]thiazin‐5‐yl]pyrimidine‐ 2,4(1H,3H)‐dione ( 1b ), are described, the key step being an intramolecular hetero‐Michael addition. Their structures and conformations, previously solved by X‐ray crystallography, were analyzed in more detail, using 1D‐ and 2D‐NMR as well as HR‐MS analyses. 相似文献
10.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(5):564-570
As part of a project studying the secondary metabolites extracted from the Chilean flora, we report herein three new β‐agarofuran sesquiterpenes, namely (1S,4S,5S,6R,7R,8R,9R,10S)‐6‐acetoxy‐4,9‐dihydroxy‐2,2,5a,9‐tetramethyloctahydro‐2H‐3,9a‐methanobenzo[b]oxepine‐5,10‐diyl bis(furan‐3‐carboxylate), C27H32O11, ( II ), (1S,4S,5S,6R,7R,9S,10S)‐6‐acetoxy‐9‐hydroxy‐2,2,5a,9‐tetramethyloctahydro‐2H‐3,9a‐methanobenzo[b]oxepine‐5,10‐diyl bis(furan‐3‐carboxylate), C27H32O10, ( III ), and (1S,4S,5S,6R,7R,9S,10S)‐6‐acetoxy‐10‐(benzoyloxy)‐9‐hydroxy‐2,2,5a,9‐tetramethyloctahydro‐2H‐3,9a‐methanobenzo[b]oxepin‐5‐yl furan‐3‐carboxylate, C29H34O9, ( IV ), obtained from the seeds of Maytenus boaria and closely associated with a recently published relative [Paz et al. (2017). Acta Cryst. C 73 , 451–457]. In the (isomorphic) structures of ( II ) and ( III ), the central decalin system is esterified with an acetate group at site 1 and furoate groups at sites 6 and 9, and differ at site 8, with an OH group in ( II ) and no substituent in ( III ). This position is also unsubstituted in ( IV ), with site 6 being occupied by a benzoate group. The chirality of the skeletons is described as 1S,4S,5S,6R,7R,8R,9R,10S in ( II ) and 1S,4S,5S,6R,7R,9S,10S in ( III ) and ( IV ), matching the chirality suggested by NMR studies. This difference in the chirality sequence among the title structures (in spite of the fact that the three skeletons are absolutely isostructural) is due to the differences in the environment of site 8, i.e. OH in ( II ) and H in ( III ) and ( IV ). This diversity in substitution, in turn, is responsible for the differences in the hydrogen‐bonding schemes, which is discussed. 相似文献
11.
Du‐Qiang Luo Yuan Gao Xiao‐Long Yang Jian‐Guo Tang Li‐Yan Zhao Ji‐Kai Liu 《Helvetica chimica acta》2007,90(6):1112-1116
Two new highly oxidized humulane sesquiterpenes, mitissimols F ( 1 ) and G ( 2 ), were isolated from the fruiting bodies of Lactarius mitissimus. Their structures were elucidated by using extensive spectroscopic techniques including 1D‐ and 2D‐NMR experiments. The absolute configuration of mitissimol F ( 1 ) was determined by 1H‐NMR resolution of its diastereoisomeric α‐methoxy‐α‐(trifluoromethyl)benzeneacetates (MTPA). It was shown to be (1S,3E,6S,8R,9R,10S,11R)‐8,9 : 10,11‐diepoxy‐1,6‐dihydroxyhumul‐3‐en‐5‐one (=(1S,2R,4R,6S,8E,11S,12R)‐6,11‐dihydroxy‐1,6,10,10‐tetramethyl‐3,13‐dioxatricyclo[10.1.0.02,4]tridec‐8‐en‐7‐one). 相似文献
12.
Jianping Zhao Ilias Muhammad D. Chuck Dunbar Ikhlas A. Khan Nikolaus H. Fischer Frank R. Fronczek 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o195-o198
A low‐temperature structure of ginkgolide A monohydrate, (1R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11aS)‐3‐(1,1‐dimethylethyl)‐hexahydro‐4,7b‐dihydroxy‐8‐methyl‐9H‐1,7a‐epoxymethano‐1H,6aH‐cyclopenta[c]furo[2,3‐b]furo[3′,2′:3,4]cyclopenta[1,2‐d]furan‐5,9,12(4H)‐trione monohydrate, C20H24O9·H2O, obtained from Mo Kα data, is a factor of three more precise than the previous room‐temperature determination. A refinement of the ginkgolide A monohydrate structure with Cu Kα data has allowed the assignment of the absolute configuration of the series of compounds. Ginkgolide C sesquihydrate, (1S,2R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11S,11aR)‐3‐(1,1‐dimethylethyl)‐hexahydro‐2,4,7b,11‐tetrahydroxy‐8‐methyl‐9H‐1,7a‐epoxymethano‐1H,6aH‐cyclopenta[c]furo[2,3‐b]furo[3′,2′:3,4]cyclopenta[1,2‐d]furan‐5,9,12(4H)‐trione sesquihydrate, C20H24O11·1.5H2O, has two independent diterpene molecules, both of which exhibit intramolecular hydrogen bonding between OH groups. Ginkgolide J dihydrate, (1S,2R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11aS)‐3‐(1,1‐dimethylethyl)‐hexahydro‐2,4,7b‐trihydroxy‐8‐methyl‐9H‐1,7a‐epoxymethano‐1H,6aH‐cyclopenta[c]furo[2,3‐b]furo[3′,2′:3,4]cyclopenta[1,2‐d]furan‐5,9,12(4H)‐trione dihydrate, C20H24O10·2H2O, has the same basic skeleton as the other ginkgolides, with its three OH groups having the same configurations as those in ginkgolide C. The conformations of the six five‐membered rings are quite similar across ginkgolides A–C and J, except for the A and F rings of ginkgolide A. 相似文献
13.
Stefania Costa Pier Paolo Giovannini Giancarlo Fantin Alessandro Medici Paola Pedrini 《Helvetica chimica acta》2013,96(6):1062-1071
The biotransformations of hyodeoxycholic acid with various Rhodococcus spp. are reported. Some strains (i.e., Rhodococcus zopfii, Rhodococcus ruber, and Rhodococcus aetherivorans) are able to partially degrade the side chain at C(17) to afford 6α‐hydroxy‐3‐oxo‐23,24‐dinor‐5β‐cholan‐22‐oic acid ( 2 ; 23%) and 6α‐hydroxy‐3‐oxo‐23,24‐dinorchol‐1,4‐dien‐22‐oic acid ( 3 ; 23–30%), together with two new 9,10‐secosteroids 4 and 5 (10–45%), still bearing the partial side chain at C(17) and adopting an intramolecular hemiacetal form. In addition, the 9,10‐secosteroid 5 showed an unprecedented C(4)‐hydroxylation. The new secosteroids were fully characterized by MS, IR, NMR, and 2D‐NMR analyses. 相似文献
14.
The cross‐aldolization of (−)‐(1S,4R,5R,6R)‐6‐endo‐chloro‐5‐exo‐(phenylseleno)‐7‐oxabicyclo[2.2.1]heptan‐2‐one ((−)‐ 25 ) and of (+)‐(3aR,4aR,7aR,7bS)‐ ((+)‐ 26 ) and (−)‐(3aS,4aS,7aS,7bR)‐3a,4a,7a,7b‐tetrahydro‐6,6‐dimethyl[1,3]dioxolo[4,5]furo[2,3‐d]isoxazole‐3‐carbaldehyde ((−)‐ 26 ) was studied for the lithium enolate of (−)‐ 25 and for its trimethylsilyl ether (−)‐ 31 under Mukaiyama's conditions (Scheme 2). Protocols were found for highly diastereoselective condensation giving the four possible aldols (+)‐ 27 (`anti'), (+)‐ 28 (`syn'), 29 (`anti'), and (−)‐ 30 (`syn') resulting from the exclusive exo‐face reaction of the bicyclic lithium enolate of (−)‐ 25 and bicyclic silyl ether (−)‐ 31 . Steric factors can explain the selectivities observed. Aldols (+)‐ 27 , (+)‐ 28 , 29 , and (−)‐ 30 were converted stereoselectively to (+)‐1,4‐anhydro‐3‐{(S)‐[(tert‐butyl)dimethylsilyloxy][(3aR,4aR,7aR,7bS)‐3a,4a,7a,7b‐tetrahydro‐6,6‐dimethyl[1,3]dioxolo[4,5]‐furo[2,3‐d]isoxazol‐3‐yl]methyl}‐3‐deoxy‐2,6‐di‐O‐(methoxymethyl)‐α‐D ‐galactopyranose ((+)‐ 62 ), its epimer at the exocyclic position (+)‐ 70 , (−)‐1,4‐anhydro‐3‐{(S)‐[(tert‐butyl)dimethylsilyloxy][(3aS,4aS,7aS,7bR)‐3a,4a,7a,7b‐tetrahydro‐6,6‐dimethyl[1,3]dioxolo[4,5]furo[2,3‐d]isoxazol‐3‐yl]methyl}‐3‐deoxy‐2,6‐di‐O‐(methoxymethyl)‐α‐D ‐galactopyranose ((−)‐ 77 ), and its epimer at the exocyclic position (+)‐ 84 , respectively (Schemes 3 and 5). Compounds (+)‐ 62 , (−)‐ 77 , and (+)‐ 84 were transformed to (1R,2R,3S,7R,8S,9S,9aS)‐1,3,4,6,7,8,9,9a‐octahydro‐8‐[(1R,2R)‐1,2,3‐trihydroxypropyl]‐2H‐quinolizine‐1,2,3,7,9‐pentol ( 21 ), its (1S,2S,3R,7R,8S,9S,9aR) stereoisomer (−)‐ 22 , and to its (1S,2S,3R,7R,8S,9R,9aR) stereoisomer (+)‐ 23 , respectively (Schemes 6 and 7). The polyhydroxylated quinolizidines (−)‐ 22 and (+)‐ 23 adopt `trans‐azadecalin' structures with chair/chair conformations in which H−C(9a) occupies an axial position anti‐periplanar to the amine lone electron pair. Quinolizidines 21 , (−)‐ 22 , and (+)‐ 23 were tested for their inhibitory activities toward 25 commercially available glycohydrolases. Compound 21 is a weak inhibitor of β‐galactosidase from jack bean, of amyloglucosidase from Aspergillus niger, and of β‐glucosidase from Caldocellum saccharolyticum. Stereoisomers (−)‐ 22 and (+)‐ 23 are weak but more selective inhibitors of β‐galactosidase from jack bean. 相似文献
15.
Chitrasen Gupta Subedar Prasad Mahendra Sahai Teigo Asai Noriyuki Hara Yoshinori Fujimoto 《Helvetica chimica acta》2010,93(10):1925-1932
Six new lanostane triterpenes, artabotryols A, B, C1, C2, D, and E ( 1, 2, 3a, 3b, 4 , and 5 , resp.) have been isolated from the seeds of Artabotrys odoratissimus (Annonaceae). Their structures have been established as (3α,22S,25R)‐3‐hydroxy‐22,26‐epoxylanost‐8‐en‐26‐one ( 1 ), (3α,22S,25R)‐22,26‐epoxylanost‐8‐ene‐3,26‐diol ( 2 ), (3α,22S,25R,26R)‐26‐methoxy‐22,26‐epoxylanost‐8‐en‐3‐ol ( 3a ), (3α,22S,25R, 26S)‐26‐methoxy‐22,26‐epoxylanost‐8‐en‐3‐ol ( 3b ), (3α,22S,25R)‐3,22‐dihydroxylanost‐8‐en‐26‐oic acid ( 4 ) and (3α,7α,11α,22S,25R)‐3,7,11‐trihydroxy‐22,26‐epoxylanost‐8‐en‐26‐one ( 5 ) by spectroscopic studies and chemical correlations. 相似文献
16.
N‐Substituted (3S,4S)‐ and (3R,4R)‐pyrrolidine‐3,4‐diols 9 and 10 , respectively, were derived from (+)‐L ‐ and (?)‐D ‐tartaric acid, respectively. Compounds 9k, 9l , and 9m with the N‐substituents, BnNH(CH2)2, 4‐PhC6H4CH2NH(CH2)2 and 4‐ClC6H4CH2NH(CH2)2, respectively, showed modest inhibitory activities toward α‐D ‐amyloglucosidases from Aspergillus niger and from Rhizopus mold (Table 1). Unexpectedly, several (3R,4R)‐pyrrolidine‐3,4‐diols 10 showed inhibitory activities toward α‐D ‐mannosidases from almonds and from jack bean (Table 3). N‐Substitution by the NH2(CH2)2 group, i.e., 10g , led to the highest potency. 相似文献
17.
Jiang Wan Xiao-Juan Wang Nan Guo Xi-Ying Wu Juan Xiong Yi Zang Chun-Xiao Jiang Bing Han Jia Li Jin-Feng Hu 《Molecules (Basel, Switzerland)》2021,26(7)
During a phytochemical investigation of the unripe fruits of Rubus chingii Hu (i.e., Fructus Rubi, a traditional Chinese medicine named “Fu-Pen-Zi”), a number of highly oxygenated terpenoids were isolated and characterized. These included nine ursane-type (1, 2, and 4–10), five oleanane-type (3, 11–14), and six cucurbitane-type (15–20) triterpenoids, together with five ent-kaurane-type diterpenoids (21–25). Among them, (4R,5R,8R,9R,10R,14S,17S,18S,19R,20R)-2,19α,23-trihydroxy-3-oxo-urs-1,12-dien-28-oic acid (rubusacid A, 1), (2R*,4S*,5R*,8R*,9R*,10R*,14S*,17S*, 18S*,19R*,20R*)-2α,19α,24-trihydroxy-3-oxo-urs-12-en-28-oic acid (rubusacid B, 2), (5R,8R,9R,10R, 14S,17R,18S,19S)-2,19α-dihydroxy-olean-1,12-dien-28-oic acid (rubusacid C, 3), and (3S,5S,8S,9R, 10S,13R,16R)-3α,16α,17-trihydroxy-ent-kaur-2-one (rubusone, 21) were previously undescribed. Their chemical structures and absolute configurations were elucidated on the basis of spectroscopic data and electronic circular dichroism (ECD) analyses. Compounds 1 and 3 are rare naturally occurring pentacyclic triterpenoids featuring a special α,β-unsaturated keto-enol (diosphenol) unit in ring A. Cucurbitacin B (15), cucurbitacin D (16), and 3α,16α,20(R),25-tetrahydroxy-cucurbita-5,23- dien-2,11,22-trione (17) were found to have remarkable inhibitory effects against NF-κB, with IC50 values of 0.08, 0.61, and 1.60 μM, respectively. 相似文献
18.
Guy‐Bertrand Djigoue Michel Simard Lucie‐Carolle Kenmogne Donald Poirier 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(6):o231-o234
The title compounds, (3R,5S,5′R,8R,9S,10S,13S,14S)‐10,13‐dimethyl‐5′‐(2‐methylpropyl)tetradecahydro‐6′H‐spiro[cyclopenta[a]phenanthrene‐3,2′‐[1,4]oxazinane]‐6′,17(2H)‐dione, C26H41NO3, (I), and methyl (2R)‐2‐[(3R,5S,8R,9S,10S,13S,14S)‐10,13‐dimethyl‐2′,17‐dioxohexadecahydro‐3′H‐spiro[cyclopenta[a]phenanthrene‐3,5′‐[1,3]oxazolidin‐3′‐yl]]‐4‐methylpentanoate, C28H43NO5, (II), possess the typical steroid shape (A–D rings), but they differ in their extra E ring. The azalactone E ring in (I) shows a half‐chair conformation, while the carbamate E ring of (II) is planar. The orientation of the E‐ring substituent is clearly established and allows a rationalization of the biological results obtained with such androsterone derivatives. 相似文献
19.
Two new flavanols, (8S,9R)‐9,10‐dihydro‐5,9‐dihydroxy‐8‐(3,4,5‐trimethoxyphenyl)‐2H,8H‐benzo[1,2‐b:3,4‐b′]dipyran‐2‐one ( 1 ) and (2S,3R)‐3,4‐dihydro‐3,5‐dihydroxy‐2‐(3,4,5‐trimethoxyphenyl)‐2H,8H‐benzo[1,2‐b:3,4‐b′]dipyran‐8‐one ( 2 ), were isolated from the stems of Glycosmis pentaphylla. The structures of these compounds were determined by extensive spectroscopic (UV, IR, HR‐ESI‐MS, 1D‐ and 2D‐NMR) analyses. The cytotoxic activities of these compounds were evaluated using the MTT method. The results showed that compounds 1 and 2 exhibited considerable cytotoxic activities against HL‐60 and A549 cell lines. 相似文献
20.
Novel chiral PEDOTs for selective recognition of 3,4‐dihydroxyphenylalanine enantiomers: Synthesis and characterization 下载免费PDF全文
Xuemin Duan Jingkun Xu Dufen Hu Kaixin Zhang Xiaofei Zhu Hui Sun Shouli Ming Zhipeng Wang Shijie Zhen 《Journal of polymer science. Part A, Polymer chemistry》2015,53(19):2238-2251
Two new 3,4‐ethylenedioxythiophene (EDOT) derivatives, (2R)‐(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methyl 2‐phenylpropanoate ((R)‐EDTM‐PP) and (2S)‐(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methyl 2‐phenylpropanoate ((S)‐EDTM‐PP), were synthesized and electropolymerized in dichloromethane (CH2Cl2) and terabutylammonium hexafluorophosphate (Bu4NPF6) system. As chiral electrodes, poly((2R)‐(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methyl 2‐phenylpropanoate) ((R)‐PEDTM‐PP) and poly((2S)‐(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methyl 2‐phenylpropanoate) ((S)‐PEDTM‐PP)‐modified glassy carbon electrodes (GCEs) were employed to successfully recognize 3,4‐dihydroxyphenylalanine (DOPA) enantiomers. Cyclic voltammetry presents that (R)‐PEDTM‐PP and (S)‐PEDTM‐PP had good redox activity and stability. Spectroelectrochemistry studies revealed (R)‐PEDTM‐PP and (S)‐PEDTM‐PP polymers have electronic bandgap of 1.68 and 1.66 eV, and could be reversibly oxidized and reduced accompanying with obvious color changes from dark blue to light purple. In addition, the electrochemical behavior, structural characterization, thermal stability, morphology and circular dichroism of (R)‐PEDTM‐PP and (S)‐PEDTM‐PP films were investigated in detail. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2238–2251 相似文献