Three new isomeric biisoflavonoids, dapholidins A–C ( 1 – 3 , resp.), have been isolated from the AcOEt‐soluble fraction of the MeOH‐soluble extract of the roots of Daphne oleoides, along with the known compounds daphwazirin ( 4 ), daphnetin 8‐O‐β‐D ‐glucopyranoside ( 5 ), daphnin ( 6 ), daphneticin 4″‐O‐β‐D ‐glucopyranoside ( 7 ), and 6,7‐dihydroxy‐3‐methoxy‐8‐[2‐oxo‐2H‐1‐benzopyran‐7‐(O‐β‐D ‐glucopyranosyl)‐8‐yl]‐2H‐1‐benzopyran‐2‐one ( 8 ). The structures of the new compounds were determined by spectroscopic analyses, including 1D‐ and 2D‐NMR. 相似文献
Dimorphamides A–C ( 1 – 3 , resp.), three new polyphenolic amides, have been isolated from the BuOH‐soluble fraction of the whole plant of Atriplex dimorphostagia, along with two known compounds, thymidine and N‐[(E)‐feruloyl]tyramine. Their structures have been determined on the basis of spectral studies. 相似文献
Eremosides A–C ( 1 – 3 ), three new iridoid glucosides, were isolated from the AcOEt‐soluble fraction of the EtOH extract of the whole plant of Eremostachys loasifolia, along with buddlejoside B ( 4 ), 10‐O‐benzoylcatalpol ( 5 ), and pakiside A ( 6 ) reported for the first time from this species. The structures of these compounds were elucidated by spectroscopic data including 2D‐NMR, FAB‐MS, ESI‐MS, as well as by acid and basic hydrolyses. 相似文献
Three new clerodane diterpenoids, splendidins A–C ( 1 – 3 , resp.), were isolated from Salvia splendens, together with six known ones. Their structures were elucidated by extensive spectroscopic analysis. Splendidin C ( 3 ) was the first diterpenoid glucoside reported from this plant. These compounds were evaluated for their cytotoxic activity; however, none of them were cytotoxic. 相似文献
The morphology transition of polystyrene‐block‐poly(butadiene)‐block‐poly(2‐vinylpyridine) (SBV) triblock thin film induced in benzene vapor showing weak selectivity for PS is investigated. The order‐order transitions (OOT) in the sequence of core‐shell cylinders (C), sphere in ‘diblock gyroid’ (sdG), sphere in lamella (sL) and sphere (S) are observed. The projection along (111) direction in Gyroid phase (sdG(111)) is found to epitaxially grow from C(001) in the film. Instead of sdG(111), sdG(110)0.1875 develops to the phase of sL. Consequently, the film experiences the transition sequence of sdG(111) → sdG(211) → sdG(110)0.25 → sdG(110)0.1875 between C and sL. The mechanism is analyzed from the total surface area of the blocks.
Phytochemical investigation of Eupatorium chinense var. tozanense has resulted in the isolation of three new germacranolides, designated as eupatozansins A–C ( 1 – 3 ), along with five known compounds, (5S,6R,7R,8R)‐8‐angeloyloxy‐2‐oxoguaia‐1(10),3,11(13)‐trien‐12,6‐olide ( 4 ), costunolide ( 5 ), leptocarpin ( 6 ), 2α‐hydroxyeupatolide 8‐O‐angelate ( 7 ), and quercetin ( 8 ). The structures of the new compounds were identified by 1D and 2D NMR experiments, as well as high‐resolution mass spectrometry. The in vitro cytotoxic activities of compounds 1 – 8 were evaluated. 相似文献
The title compound, 2,2′‐(oxalyldiimino)bis(3‐methylbutanoic acid), C12H20N2O6, possesses a centre of symmetry. In the crystal, molecules are connected by hydrogen bonds between oxamide and carboxyl groups, similar to the pattern of the monoclinic forms of HO–Gly–CO–CO–Gly–OH and HO–Aib–CO–CO–Aib–OH (Gly is glycine and Aib is 2‐aminoisobutyric acid). The characteristic torsion angles in the title compound are close to those in peptide α‐helices. 相似文献
Phytochemical analyses were carried out on the rhizomes of Clintonia udensis (Liliaceae) with particular attention paid to the steroidal glycoside constituents, resulting in the isolation of three new polyhydroxylated spirostanol glycosides, named clintonioside A ( 1 ), B ( 2 ), and C ( 3 ). On the basis of their spectroscopic data, including 2D‐NMR spectroscopy, in combination with acetylation and hydrolytic cleavage, the structures of 1 – 3 were determined to be (1β,3β,23S,24S,25R)‐1,23,24‐trihydroxyspirost‐5‐en‐3‐yl O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[α‐L ‐rhamnopyranosyl‐(1→2)]‐β‐D ‐glucopyranoside ( 1 ), (1β,3β,23S,24S)‐3,21,23,24‐tetrahydroxyspirosta‐5,25(27)‐dien‐1‐yl O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[β‐D ‐xylopyranosyl‐(1→3)]‐β‐D ‐glucopyranoside ( 2 ), and (1β,3β,23S,24S)‐21‐(acetyloxy)‐24‐[(6‐deoxy‐β‐D ‐gulopyranosyl)oxy]‐3,23‐dihydroxyspirosta‐5,25(27)‐dien‐1‐yl O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[β‐D ‐xylopyranosyl‐(1→3)]‐β‐D ‐glucopyranoside ( 3 ). 相似文献
A meso–meso‐linked diphenylamine‐fused porphyrin dimer and its methoxy‐substituted analogue were synthesized from a meso–meso‐linked porphyrin dimer by a reaction sequence involving Ir‐catalyzed β‐selective borylation, iodination, meso‐chlorination, and SNAr reactions with diarylamines followed by electron‐transfer‐mediated intramolecular double C?H/C?I coupling. While these dimers commonly display characteristic split Soret bands and small oxidation potentials, they produced different products upon oxidation with tris(4‐bromophenyl)aminium hexachloroantimonate. Namely, the diphenylamine‐fused porphyrin dimer was converted into a dicationic closed‐shell quinonoidal dimer, while the methoxy‐substituted dimer gave a meso–meso, β‐β doubly linked porphyrin dimer. 相似文献
Three new sesquiterpenes, tuberculariols A–C ( 1 – 3 , resp.), were isolated from the mutant strain M‐741 of Tubercularia sp. TF5, an endophytic fungus of Taxus mairei. Their structures were elucidated by spectroscopic analyses including 1D‐ and 2D‐NMR experiments, and HR‐Q‐TOF‐MS. Antitumor and antibacterial properties of these compounds were evaluated. 相似文献
Wheels on water? A waterwheel‐shaped porphyrin pentamer has been synthesized by palladium‐catalyzed cross‐coupling reactions. The key intermediate is a boronate porphyrin, in which four boronic ester groups are directly attached to the meso‐positions.