改进的Perkin法催化合成香豆素

聚乙二醇;乙酸钙;改进的Perkin法催化合成香豆素     

Convenient methods for the synthesis of pentacyclic fused heterocycles with coumarin moiety

This review describes the preparation of pentacyclic fused heterocycles with the coumarin moiety. These derivatives are reported as biologically active compounds.     

新型含取代乙烯基香豆素衍生物的合成及其光学性能

利用Perkin反应和Wittig反应设计并合成了两个新型的香豆素衍生物——3-(4’-溴苯基)-7-(N-辛基-3’-溴咔唑-6’-乙烯基)香豆素(6a)和3-(4’-溴苯基)-7-(4’-甲氧基苯基-1’-乙烯基)香豆素(6b),其结构经UV,1H NMR,IR,MS和荧光光谱表征。研究结果表明,6a和6b具有荧光强度大和Stokes位移(分别为115 nm和122 nm)大的特点。     

Efficient Synthesis of Complex Oxazatricycles via Three‐Component Reaction of Isoquinolinium Salts,Acetone and Cyclic Diketones

A series of complex oxazatricyclic systems was efficiently synthesized in satisfactory yields by three‐component reaction of isoquinolinium salts, acetone, and cyclic 1,3‐dicarbonyl compounds in ethanol in the presence of triethylamine as base catalyst.     

An Efficient and Convenient Cyclization Method for the Synthesis of Flavans

Flavansrefertoalargegroupofnaturallyoccurringcompoundspossessinga2-phenyl-chromannucleus.Naturallyoccurringflavansexhibitanumberofimportantbiologicalactivitieswhichifexploitedproperly,mayleadtovaluablenewdrugsoragrochemicals'.Inflavansynthesis,thekeystepistoconstructthe3,4-dihydrobenzopyranring-Variousmethodshavebeendevelopedfortheringformation,butmostoftheminvolvemultiplestepsandgivelowoverallyields2.Inthispaper,BF3wasusedforthefirsttimeasanefficientcatalysttoformthepyranringfroml,3-diaryIp…     

Efficient Synthesis of 3-Methyl-2H-chromen-2-one: Classic Versus Microwave Conditions

The reaction of salicylaldehyde with propionic anhydride in the presence of anhydrous K₂CO₃ as catalyst afforded 3-methyl-2H-chromen-2-one (3-methylcoumarin) in good yields depending on the reaction conditions. The reaction was performed under classic thermal (55% yield) and microwave conditions (91–97% yield).

Efficient and Convenient Method for the Synthesis of Symmetrical Triindolylmethanes Catalyzed by Iodine

Indoles reacted with triethyl orthoformate in the presence of a catalytic amount of iodine at room temperature to give the corresponding symmetrical triindolylmethanes (TIMs) in good to high yields.     

Convenient and Efficient Method for the Synthesis of N-Heteroaryl Aminonaphthols under Solvent-Free Conditions

A convenient, efficient and green synthesis of N‐heteroaryl aminonaphthols has been developed by one‐pot, three‐component condensation of β‐naphthol, heteroaryl amines and substituted benzaldehydes under solvent‐free conditions at elevated temperature. The advantages of these reactions are simplicity of the reaction procedure, short reaction times, simple work‐up, catalyst‐free conditions and pure products in good to excellent yields.     

An Efficient Method for the Programmed Synthesis of Multifunctional Diketopyrrolopyrroles

A new, transformative methodology for the preparation of diketopyrrolopyrroles from aldehydes, primary amines, nitriles, and diethyl oxalacetate has been developed. It is now possible to prepare diketopyrrolopyrroles bearing an ordered arrangement of three different substituents from abundant and commercially available materials, allowing the independent regulation of all desired physicochemical properties. For the first time very electron‐rich (carbazol‐3‐yl, dimethylaminophenyl, pyrrolo[3,2‐b]pyrrolyl), and sterically hindered substituents (naphthalen‐1‐yl, quinolin‐4‐yl, acridin‐9‐yl, imidazo[1,5‐a]pyridin‐1‐yl, 2‐bromophenyl etc.) can be appended to the diketopyrrolopyrrole core by condensation of an appropriate nitrile with a pyrrolidin‐2‐one intermediate. Even greater synthetic possibilities are related to the fact that such demanding substituents as 4‐dimethylaminophenyl, indol‐3‐yl, and 2‐methoxyphenyl can be incorporated from aldehyde precursors, bypassing problems with the nitriles reactivity.     

Convenient Method for Preparation of Dialkylphosphoramidopropionic Acids and Esters

Silylation at the alpha position of N-propargyl dialkylphosphoramidates enables preparation of dialkylphosphoramido propionic acids in 50–60% yield after hydroboration/oxidation. Treatment with Amberlyst 15 resin in the presence of methanol leads to a quantitative yield of the corresponding esters.     

Convenient and Efficient Synthesis of 2,4-Dideoxy-levoglucosan

A convenient and efficient synthesis of 1,6-anhydro-2,4-dideoxy-β-D-threo-hexopyranose (2,4-dideoxy-levoglucosan) from levoglucosan has been developed. The method uses cheap reagents and requires only crystallization and distillation for preparation of pure product on a multigram scale.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

DABCO-Promoted Efficient and Convenient Synthesis of Benzofurans

An efficient and convenient synthesis of benzofurans has been described from phenacyl halides and o-hydroxy benzaldehyde in the presence of DABCO. The procedure is applicable for a variety of phenacyl halides and provide a variety of benzofurans. DABCO act as a base and as well as nucleophile.     

Efficient and Convenient One-Pot Synthesis of Dioxadiazaphophepines

The reaction of vicinal dioxime with sodium hydride in dry THF followed by addition of dichlorophosphates or dichlorothiophosphates yields 2-oxo-1,3,4,7-dioxadiazaphosphepines and 2-thioxo-1,3,4,7-dioxodiazaphosphepines in moderate to good overall yields. The products are characterized by elemental analyses, molecular weights and spectral (IR, ¹H, ¹³C and ³¹P NMR) studies. A salt elimination route is used for the synthesis of titled heterocycles.     

A New and Efficient Synthesis of Wedelolactone Derivatives

A new and facile method based on an intermolecular cycloaddition was described for the synthesis of wedelolactone derivatives.     

A Novel and Efficient Synthesis of Dronedarone Hydrochloride,an Antiarrhythmic Drug Substance

A novel and efficient synthesis of dronedarone hydrochloride starting from 2‐n‐butyl‐5‐nitrobenzofuran by employing mild and selective reaction conditions is described. The synthetic approach is operationally simple and suitable for industrial application.     

Method for a Convenient and Efficient Synthesis of Amino Acid Acrylic Monomers with Zwitterionic Structure

Ampholyte monomers with zwitterionic moiety derived from α‐amino acid, that is, L‐lysine and L‐serine, were obtained using a method in which their copper complexes could be produced in simple steps. The N‐acryloylation of L‐lysine and L‐serine was carried out by reaction between their copper complexes and acryloyl chloride. Specifically, the removal of copper from the copper complex of acryloyl amino acid through the use of 8‐hydroxyquinoline as an organic chelate precipitant increased the yield of the ampholyte monomers with zwitterionic moiety. These syntheses were easily carried out in a three‐step procedure.     

Convenient Method for the Synthesis of N-(Ethyloxycarbonyl) Ester Derivatives from Amino Acids

Amino acids upon treatment with ethyl chloroformate in methanol in the presence of potassium carbonate give the corresponding N-(ethyloxycarbonyl) amino acid ester derivatives in good yields. These derivatives can be also synthesized by performing the reaction in THF in the presence of alcohols.     

新型香豆素类荧光化合物的合成及荧光性质研究

合成了两种香豆素类荧光化合物6,8-二氯-7-羟基香豆素-3-羧酸（DClC）和6-氯-7-羟基香豆素-3-羧酸（MClC）,其中DClC未见文献报道,并通过红外光谱、核磁共振、质谱等手段对产物的结构进行了表征。同时首次研究了这两种香豆素衍生物的紫外、荧光性质,以及不同极性溶剂、pH值、表面活性剂等的影响。结果表明,pH对性质测定影响较大,当pH=10时,DClC和MClC的荧光强度明显增强。     

A Convenient and Efficient Synthesis of SLeX Analogs

Described is the preparation and use of tetrasaccharide 1, which enables a rapid and preparative scale synthesis of sialyl Lewis X (SLeX) analogs having 1-O- and 2-N-disubstituted glucosamine (GlcN) moieties. Such modifications should bring a dramatic change of the physical and pharmacological properties of the SLeX analogs. Therefore, tetrasaccharide 1 is a convenient intermediate for the synthesis of various SLeX analogs, since it has convertible 2-(trimethylsilyl)ethyl (SE) glycoside and the free amino group on GlcN moiety. The intermediate 1 was constructed from a glucosamine derivative by a highly efficient combined use of enzymatic galactosylation/sialylation and chemical fucosylation. Thus obtained 1 was converted into SLeX analogs by N-substitution followed by transformation of SE glycoside into other glycosides and deprotection. These synthesized analogs were found to inhibit cell adhesion of HL-60 cells to recombinant soluble human E-selectin.     

An Efficient and Convenient Synthesis of 5-Formylsalicylaldehyde

5-Formylsalicylaldehyde 1, which is a key intermediate of spiropyran dye and a recently developed insulin sensitivity enhancer (ISE) compounds, was prepared from 5-iodosalicylaldehyde by the palladiumcatalyzed coupling reaction with ethyl acrylate followed by ozonolysis in high overall yield (92%).