Palladium‐Catalyzed Carbonylative Synthesis of 2,3‐Disubstituted Chromones

An unexpected palladium‐catalyzed carbonylative synthesis of 2,3‐disubstituted chromones has been developed. Starting from 2‐bromofluorobenzenes and ketones, the corresponding chromones were produced in good yields. By control experiments, this transformation was found to proceed through a sequential carbonylation/Claisen–Hasse rearrangement/intramolecular nucleophilic aromatic substitution approach (S_NAr). More specifically, the reaction sequence started with a palladium‐catalyzed carbonylation of the ketone with o‐bromofluorobenzene to give the vinyl benzoates, which subsequently transformed into 1,3‐diketones via a Claisen–Hasse rearrangement. The final products were produced after an intramolecular S_NAr reaction of the in situ formed 1,3‐diketone.

     

Novel components from secretory hairs of azalea lace bugStephanitis pyrioides (Hemiptera: Tingidae)

The azalea lace bug secretes a clear fluid from secretory setae on the antennae and globulated spines on the dorsal and lateral aspects of the abdomen. The secretion contains 2-alkyl-5-hydroxychromones, the corresponding chromanones and diketones, and straight-chain aldehydes and ketones.     

Tandem Ring-Opening/Double Ring-Closing Synthesis of 1,2,4-Triazolo[1,5-a]pyridines from Chromone-Containing Acrylonitriles

We studied a reaction of chromone-containing acrylonitriles and cyanoacrylates with acid hydrazides. This reaction turned out to be a method for the synthesis of salicyloyl-substituted 1,2,4-triazolo[1,5-a]pyridines. The synthesis developed is a tandem ring-opening/double ring-closing process. This synthetic approach is characterized by low toxic solvents (ethanol, butanol) and mediator (Et₃N), 37–84% yields, non-chromatographic isolation of products, and substrate tolerance (59 examples).     

Chromones: A Promising Ring System for New Anti‐inflammatory Drugs

The quest for safer anti‐inflammatory drugs is still the focus of several medicinal chemistry programs. Chromones (4H‐chromen‐4‐ones) are a group of naturally occurring compounds ubiquitous in plants, and the chromone core has proven to be a privileged scaffold in medicinal chemistry. Herein we provide an overview of the relevance of chromones as anti‐inflammatory agents, specifically as inhibitors of cyclooxygenase (COX), 5‐lipoxygenase (5‐LOX), interleukin‐5 (IL‐5), and nitric oxide (^.NO) production. Numerous structure–activity relationships and mechanisms of action are discussed. This review is therefore intended to provide a foundation for the design and synthesis of novel chromone‐based compound libraries for further development into safer and more efficient anti‐inflammatory agents.     

Sulfur analogs of fluorinated pyrones,chromones and coumarins

This mini-review describes the synthesis and reactions of sulfur analogs of partially fluorinated pyrones, chromones, coumarins and isocoumarins and their utility as building blocks for the synthesis of trifluoromethyl-containing heterocyclic compounds with biological interest.     

Phenolic acetogenins secreted by rhododendron lace bug,Stephanitis rhododendri Horvath (Hemiptera: Tingidae)

Nymphs of the rhododendron lace bug produce from specialized setae a liquid secretion from which a number of related acetogenins have been identified. Two (2,6-dihydroxyphenyl)-1,3-diketones are the principal components and are accompanied by the corresponding chromones as well as by chromones bearing an additional phenolic oxygen.Mention of a company name or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture.     

分子碘催化合成吡唑并[3，4-b]吡啶衍生物的研究

以色酮类化合物和1，3一二取代5-氨基吡唑化合物为原料，在分子碘催化下制备一系列新颖的多取代吡唑【3，4-b】吡啶衍生物（3a-3j），收率高达85％-92％，所有化合物的结构经^1HNMR和MS等表征。     

4-色满酮芳环Mannich碱类化合物的合成及其抗血小板聚集活性研究

4-色满酮类化合物和色酮类化合物具有广泛的生物活性。笔者曾发现4-色满酮3位Mannich碱类化合物具有显著的抗血小板聚集活性,为了考察在4-色满酮的3-位Mannich碱类化合物中3-位胺甲基侧链是否为加强活性的必需基团,为确定其药效构象提供信息,笔者设计合成了4种4-色满酮芳环Mannich碱类化合物,同时又合成了3种色酮芳环Mannich碱类化合物。所合成的目标化合物均未见文献报道,其组成和结构经红外光谱、质谱和核磁共振氢谱确认。采用Born's比浊法对目标化合物进行了抗血小板聚集活性的体外筛选。实验结果表明,目标化合物对ADP和胶原诱导的家兔血小板聚集均具有显著的体外抑制活性。