Two New Chromone Glycosides from Selaginella uncinata

Two new chromone glycosides, 5-hydroxy-2,6,8-trimethylchromon-7-O-b-D-gluco- pyranoside, named uncinoside A; 5-acetoxy-2,6,8-trimethylchromone-7-O-b-D-glucopyranoside, named uncinoside B, and a known chromone compound named 8-methyl eugenitol were isolated from Selaginella uncinata. Their structures were elucidated by spectra analysis of FAB-MS, 1D NMR and 2D NMR including 1H NMR, 13C NMR, HMQC, HMBC and single-crystal X-ray diffraction techniques.

A New Chromone Derivative from Stellera chamaejasme L

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.

Novel Chromone Derivatives from Marine Fungus Aspergillus versicolor Isolated from the Sponge Xestospongia exigua

From the marine sponge Xestospongia exigua, fungal isolates of Aspergillus versicolor (Vuill)Triab were obtained. Isolation and purification of ethyl acetate extracts from culture filtrates of the fungus led to yield six new chromone derivatives namely aspergione A, aspergione B, aspergione C, aspergione D. aspergione E, aspergione F. The structures of all the new compounds were established on the basis of extensive spectroscopy (UV, MS, H-1 and C-13 NMR, COSY, HMQC and HMBC) analysis.

Sesquiterpenoids and 2-(2-Phenylethyl)chromone Derivatives from the Resinous Heartwood of Aquilaria sinensis

One novel spirolactone,aquilarisinolide(1),three new sesquiterpenoids,(2R,4S,5R,7R)-2-hydroxyeremophila-9,11-dien-8-one(2),(1R,4S,5S,7R,11R)-13-hydroxyepidaphnauran-9-en-8-one(3),and(4R,5S,7R,8S,10S,13R)-8,13-dihydroxyrotunda-1,11-dien-3-one(4),together with 13 known compounds(5-17)were isolated from the resinous heartwood of Aquilaria sinensis(Thymelaeaceae).The structures of the new compounds were elucidated based on the analysis of NMR and MS data and theoretical calculations their ECD spectra.The isolated compounds were evaluated for their protective activities against PC12 cell injury induced by corticosterone(CORT)and 1-methyl-4-phenylpyridine ion(MPP+),as well as inhibitory activities against BACE1.Compound 4,5,6-dihydroxy-2-(2-phenylethyl)chromone(5),daphnauranol B(7),6-methoxy-2-[2-(3-methyoxyphenyl)ethyl]chromone(10),isoagarotetrol(14),and 1-hydroxy-1,5-diphenylpentan-3-one(16)showed significant protective effects on CORT-induced injury in PC12 cells at a concentration of 20μM(P<0.001).Isoagarotetrol(14)showed a significant protective effect on MPP+-induced injury in PC12 cells at a concentration of 20μM(P<0.001),while compound 4 showed a moderate activity(P<0.01).The BACE1-inhibitory activities of all tested compounds were very weak with less than 30%inhibition at a concentration of 20μM.

Syntheses of 2- or 6-Substituted Chromones and Chromone Ring-opening Reaction in Polyphosphoric Acid

In an attempt to find new antitumor agents,a novel class of chromone compounds with a benzimidazole or a benzoxazole ring in positions 2 or 6 were synthesized via condensation in polyphosphoric acid(PPA) by using chromone acids as the starting materials. During the preparation process,it was found that PPA could cleave the chromone ring to produce a ring-opening compound(6). The molar ratio of the chromone compound(5) to the ring-opening compound(6) varied with the change of reaction temperature and time. Based on MTT protocol,the antitumor activity of each of the compounds obtained was evaluated against three human cancer cell lines: KB(oral epidermal),A2780(ovary) and Bel7402(liver). The IC_ 50 varied from 54.7 μmol/L to more than 180 μmol/L.

Facile Synthesis of 5-Hydroxy-2-(2-phenylethyl)chromone

5-Hydroxy-2-（2-phenylethyl）chromone（l） was synthesized from 2,6-dihydroxyacetophenone（7） obtained via four-steps resorcinol-reacting with phenylpropionic acid, the procedures involved are Baker-Venkataraman rear-rangement and cyclization which are easy to conduct, the overall yield is 32%.

Five new 2-(2-phenylethyl)chromone derivatives and three new sesquiterpenoids from the heartwood of Aquilaria sinensis, an aromatic medicine in China

Five new 2-(2-phenylethyl)chromone derivatives,(5S,6R,7R,8S,7ʹR)-7ʹ-hydroxyagarotetrol(1),(5S,6R,7R,8S,7ʹS)-7ʹ-hydroxyagarotetrol(2),(6S,7S,8R)-2-[2-(4-methoxyphenyl)ethyl]-6,7,8-trihydroxy-5,6,7,8-tetrahydrochromone(3),(6S,7S,8R)-2-(2-phenylethyl)-6,7,8-trihydroxy-5,6,7,8-tetrahydrochromone(4),(5S,6R,7S,8R)-2-(2-phenylethyl)-5,6,7-trihydroxy-5,6,7,8-tetrahydro-8-[2-(2-phenylethyl)-7-methoxychromonyl-6-oxy]chromone(5),three new sesquiterpenoids,(4S,5S,7S,8S,10S,13R)-7,8,13-trihydroxyrotunda-1,11-dien-3-one(6),(4S,5S,7S,8S,10S,13S)-7,8,13-trihydroxyrotunda-1,11-dien-3-one(7),and(4R,5S,7S,8S,10S,13S)-7,8,13-trihydroxyrotunda-1,11-dien-3-one(8),along with 14 known compounds were isolated from the resinous heartwood of Aquilaria sinensis(Thymelaeaceae).The chemical structures of these new compounds were elucidated by 1D and 2D NMR and MS data,single-crystal X-ray diffraction analysis,and electronic circular dichroism(ECD)calculations.The neuroprotective activities of these isolates were evaluated using an in vitro model of rat adrenal pheochromocytoma(PC12)cell injury induced by corticosterone.At concentrations from 5 to 40μM,compounds 4 and 6,agarotetrol(9),and 6-hydroxy-2-(2-phenylethyl)chromone(17)showed significant protective activities against corticosterone-induced PC12 cell injury(P<0.001).

Process for the Preparation of Chromones, Isoflavones and Homoisoflavones Using Vilsmeier Reagent Generated from Phthaloyl Dichloride and DMF

Vilsmeier reagent formed from phthaloyl dichloride and DMF was found to be very effective for converting 2-hydroxyacetophenones, deoxybenzoins and dihydrochalcones into corresponding chromones, isoflavones and homoisoflavones with excellent yield. This method offers significant advantages such as efficiency and mild reaction conditions with shorter reaction time.

Chromonic溶致液晶及调控研究进展

Chromonic溶致液晶(Lyotropic Chromonic Liquid Crystals,LCLCs)是由可溶性芳香族化合物自组装形成的一类溶致液晶。由于其丰富的物理各向异性、生物兼容性以及可调控性,LCLCs在生物检测、细菌操控等应用领域具有重要的研究价值。本文回顾了LCLCs调控方面的研究,简要介绍了其特性,重点分析了外场调控、掺杂等调控手段对LCLCs的影响,最后讨论和总结了可行的调控手段和未来的发展路线。

Synthesis, nematicidal activity and docking study of novel chromone derivatives containing substituted pyrazole

A series of chromone derivatives containing substituted pyrazole were designed and synthesized.Preliminary bioassays showed that most of the synthesized compounds exhibited good nematicidal activity in vivo against Meloidogyne incognita at 10 mg/L. Among the tested compounds, A10 and A11 exhibited 100% inhibition rates. In addition, the molecular docking results indicated that both compound A10 and A11 interacts with amino acid residue Tyr121, Trp279, Tyr70, Trp84 and Phe330 of ACh E via hydrogen bond and p–p stacking. This investigation suggested that the chromone containing substituted pyrazole scaffold could be further optimized to explore novel, high-bioactivity nematicidal leads.

2-(2-Phenylethyl)chromones from Endophytic Fungal Strain Botryosphaeria rhodina A13 from Aquilaria sinensis

Objective To study the characteristic 2-（2-phenylethyl）chromone components of endophytic fungal strain of Aquilaria sinensis by solid culture. Methods The compounds were isolated by various chromatographic methods such as silica gel, reverse-phase silica gel, Sephadex-LH20 column chromatography as well as crystallization. Results Seven 2-（2-phenylethyl）chromone analogues were isolated from the solid culture of Botryosphaeria rhodina A13. Their structures were established by spectral data as well as physicochemical properties, and identified as 6-hydroxy-7-methoxy-2-（2-phenylethyl）chromone （1）, 6,7-dimethoxy-2-（2-phenylethyl） chromone （2）, （5S,6R,7S,8R）-2-（2-phenylethyl）-5,6,7,8-tetrahydrchromone （3）, 6- hydroxy-2-（2-phenylethyl）chromone （4）, 4＇-hydroxy-2-（2-phenylethyl）chromone （5）, 6-methoxy-2-phenethyl-4H-chromen-4-one （6）, and 6-methoxy-2-（4＇-methoxy-phenethyl）-4H-chromen-4-one （7）. Conclusion All of the compounds are isolated for the first time from the genus Botryosphaeria. This research opens up a new vista to produce the characteristic components of agarwood by endophytic fungi.

Recent advances in the diversification of chromones and flavones by direct C-H bond activation or functionalization

Chromone and flavone are both central backbones of natural products and clinical medicines.Synthesis of diversely functionalized chromones and flavones constitutes significant research contents of the modern synthetic science because abundant molecular libraries of such types are crucial in providing candidate compounds for the discovery of new pharmaceuticals and functional materials.The direct C—H bond activation or functionalization on these heterocyclic backbones provides highly powerful tools for the rapid accesses to densely functionalized chromone and flavone derivatives.Considering the importance of the functionalized chromone and flavone compounds as well as the notable advances in the synthesis of such products by direct C—H activation or functionalization,we review herein the research advances in the C—H bond activation and functionalization reactions of chro mone and flavones,in hope of showing the current states and promise of the research domain.

FeCl3- and GaCl3-Catalyzed Dehydrative Coupling Reaction of Chromone-Derived Morita-Baylis-Hillman Alcohols with Terminal Alkynes

FeCl3- and GaCl3-catalyzed dehydrative coupling reactions of chromone-derived Morita-Baylis-Hillman （MBH） alcohols with terminal alkynes were developed. The reactions provided exclusively a-regioselective and acetylene-substituted products in good yields.

Selective detection of Zn^(2+) and Cd^(2+) ions in water using a host-guest complex between chromone and Q[7]

In this paper,the host-guest interaction of cucurbit[7]uril(Q[7]) and chromone(CMO) has been developed as a fluorescent probe for the highly selective detection of Zn2+ and Cd^(2+) in water based on a chelation-enhanced fluorescence(CHEF) mechanism.There was a good linear relationship between the fluorescence intensity of the CMO@Q[7] probe and the concentration of Zn^(2+ )or Cd^(2+) in the range of 0-3.0×10^(-5) mol/L and the detection limit for Zn^(2+) and Cd2+ was found to be 2.03×10^(-6) mol/L and 1.89×10^(-6)mol/L,respectively.The X-ray crystal structure indicated that different coordination fashions were triggered by Zn^(2+) and Cd^(2+ )in the CMO@Q[7] complexes,respectively.However,both metal ions coordinated with the carbonyl oxygen of CMO,which was encapsulated in the cavity of Q[7],thus leading to the enhancement of recognition fluorescence emission of CMO.

Synthesis of 3-thiocyanated chromones via TCCA/NH_(4)SCN-mediated cyclization/thiocyanation of alkynyl aryl ketones

3-Thiocyanated chromones was conveniently synthesized from alkynyl aryl ketones using commercially available,inexpensive trichloroisocyanuric acid(TCCA)as oxidant and NH_(4)SCN as thiocyanato(SCN)source.This metalfree approach is postulated to first in situ generate thiocyanogen chloride(Cl-SCN)from the reaction of TCCA and NH_(4)SCN,followed by a rare efficient electrophilic thiocyano oxyfunctionalization of alkynes enabled by the reactive electrophilic species generated thereof.

Aloesin as a medical food ingredient for systemic oxidative stress of diabetes

Diabetes is a chronic disease that requires a long term management where oxidative stress plays a pivotal role in disease progression and intensifying secondary complications. In spite of all the research on diabetes and recent advances in diabetes treatments, the reality is that there is no cure for diabetes and its devastating complications. While currently available anti-diabetic therapies are effective in reducing blood glucose level, they are not without associated side effects when they are used for a long term applications. As a result, physicians and patients are inclining more towards to a safer therapy with less serious side effects in the form of medicinal foods and botanical alternatives that are suitable for chronic usage. Aloesin, an Aloe chromone, has previously been formulated with an aloe polysaccharide to give a composition called Loesyn, where it showed significant impact in reducing glycosylated hemoglobin, fasting blood glucose, fructosamine and plasma insulin level in humans. Radical scavenging activities of chromones and polysaccharides from Aloe have also been reported. Here we rationalize the relevance of use of Aloesin alone or in a standardized blend with Aloe polysaccharides, as a potential medical food to manage systemic oxidative stress and/or high blood glucose of diabetes.

Dynamic analysis of gene expression and determination of chemicals in agarwood in Aquilaria sinensis

Agarwood is the resinous heartwood of Aquilaria species.However,low yields and high costs of existing stimulation methods have led to the need for new techniques to produce agarwood rapidly and effectively.We developed a biological agarwood-inducing technique(Agar-Bit)that produces high yields and quality within 6 months.To better understand agarwood formation by Agar-Bit,dynamic gene expressions of key synthetases pathways of sesquiterpenes and chalcone-related enzymes at different times were determined after both Agar-Bit and the traditional burning chisel drilling(BCD)stimulation on Aquilaria sinensis trees.The qRT-PCR results show that some characteristic synthase genes were expressed at greatly different levels and times compared with the controls.For the Agar-Bit technology,main changes were after the 3rd or 5th month,while BCD expression clearly changed at the 5th month.Essential oils and total chromone contents were simultaneously determined.In the Agar-Bit group,both were higher and similar to natural levels.The Agar-Bit methodology is a new option for producing agarwood as demonstrated by genetic and chemical aspects.The differences in gene expression within 6 months for both groups indicates that the mechanisms of the two methods are different.These findings provide information on genetic variation during the process of agarwood formation.

A convenient synthesis of 6-demethoxycapillarisin

A convenient and effective method for the synthesis of 6-demethoxycapillarisin was described. The highlight was involved in a simple access to the key intermediate 2-ethylthio-5,7-dimethoxy-4H-chromen-4-one from the inexpensive 2,4,6-trihydroxyace- tophenone, using AICl3 as the demethylation reagent.

Diverse Polyphenols from Hypericum faberi

Six new polyphenols with diferent isoprenylated xanthones,isoprenylated acylphloroglucinols,and chromone architectures,hyperfaberols A-F(1-6),were isolated from the whole plants of Hypericum faberi along with seven other related known compounds.In which hyperfaberols A/B(1/2)and 12-13 were isoprenylated xanthones,hyperfaberols C-E(3-5)and 8-11 were seven isoprenylated acylphloroglucinol derivatives,while 6-7 were two chromones.Their structures were elucidated by comprehensive analysis of their spectroscopic data as well as detailed comparison with the literature data.Compounds 1 and 11 showed cytotoxities against the human esophageal cancer cell line(ECA-109)and the pancreatic tumor cell line(PANC-1)in vitro,respectively.

Nano structured spinel Co3O4-catalyzed four component reaction:A novel synthesis of Ugi adducts from aryl alcohols as a key reagent

A simple one pot procedure for the synthesis of α-amino acyl amide with chromone,indole,and napthalene substitution pattern is presented.This protocol involves the nano structured spinel Co3O4catalysed coupling of aryl alcohols,anilines,carboxylic acids and tert-butyl isocyanide.The salient features of this protocol were simple procedure,mild reaction condition and high yield.