Novel and Convenient Synthesis of Benzofurans from Dihydrocoumarins

7‐Hydroxy‐3,4‐dihydrocoumarin‐4‐carboxylic acid ( 7 ), conveniently prepared from m‐resorcinol and maleic anhydride, was surprisingly transformed by acid anhydride and pyridine into the corresponding ketone, 4‐alkanoyl analog 11 . The latter reacted in turn with acidic alcohol yielding benzofuran‐3‐yl‐acetic ester 16.     

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.]     

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.     

Aqueous-Phase Synthesis of 2-Aminothiazole and 2-Iminothiazolidine Derivatives catalyzed by Diammonium Hydrogen Phosphate and DABCO

2-Aminothiazole and 2-iminothiazolidine derivatives were synthesized from the reaction of phenacyl bromide, thiourea, and its derivatives in aqueous media catalyzed by diammonium hydrogen phosphate (10%) and DABCO (10%) at room temperature in an efficient and simple procedure.     

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%).     

Convenient, Efficient One-Pot Synthesis of Ferrocenylcyanide

In asymmetric catalysis, chiral (central chiral, planar chiral, axial chiral) ferrocenylligands is one of the most successful class of auxiliaries in recent years, and some ofthem have reached the stage of industrial applications'. But many challenges remain forthe synthesis of the intermediate. One of them is how to get ferrocenylcyanide I directlyfrom ferrocenecarboxyaldehyde 2, which can be easily prepared according to thecorresponding literature2. As far as known, I is an important interm…     

Cis-1,4-bis(triphenylphosphonium)-2-butene Peroxodisulfate as an Efficient Reagent for the Synthesis of Phenacyl Thiocyanates and Phenacyl Azides

Styrenes efficiently undergo thiocyanation and azidation with cis-1,4-bis(triphenylphosphonium)-2-butene peroxodisulfate at 0 °C to furnish the corresponding thiocyanatoketones and azidoketones. This method is a direct, one-pot synthesis under mild condition using methanol as solvent.     

Convenient and Efficient Synthesis of L—Rhamnopyranosyl Phosphoramidates via H—Phosphonate

It is known that saccharides linked to proteins via a phosphoester hinge can function as immunological determinants. Under regular physiological conditions, it has been suggested that the role of phosphonate group is to direct the protease towards basic substrates1. Phosphoramidon a, which was isolated from a culture filtrate, is a potent inhibitor of the thermolysin, a metallo-endopeptidase. It is a glycosylated dipeptide, which has a L-rhamnose attached to the N-terminal of Leu-Trp dipep…     

Convenient,Efficient Synthesis of Amide-Thioethers in Ionic Liquids

An improved method for the synthesis of carboxamide ligands containing thioether donor sites is described. This replaces the pyridine as the reaction medium used in the classical method by tetrabutylammonium bromide. The desired products, 1,4-bis[o-(R-2-carboxamidophenyl)]-1,4-dithiobutane, R = quinoline (1), furan (2), thiophene (3), pyridine (4), and pyrazine (5), were obtained in good yields and shorter reaction times.     

Synthesis of a new palladium salt using N‐benzyl DABCO chloride and its application in Suzuki reaction

A palladium catalyst was synthesized using N‐benzyl DABCO chloride and palladium chloride. The structure of this catalyst was characterized and then the catalyst was used in Suzuki cross‐ coupling reaction of different aryl halides with arylboronic acids. All substrates afforded the corresponding products in good to high yields in the presence of low amounts of the catalyst. Under the heating conditions employed, cheaper and more available aryl chlorides gave relatively high yields in the Suzuki reaction. Copyright © 2012 John Wiley & Sons, Ltd.     

Dehydration Rearrangements of Derivatives of Methylenedihydrobenzofuran - a New Path to Substituted Benzofurans

When heated with acidic agents derivatives of 3-amino-2-(hydroxydialkylmethyl)methylene-2,3-dihydrobenzofuran undergo rapid dehydration and rearrangement to substituted 2-alkenyl-3-aminobenzofurans.     

Convenient and Efficient Synthesis of 1-Oxo-1,2,3,4-tetrahydrocarbazoles via Fischer Indole Synthesis

A convenient synthesis of 1-oxo-1,2,3,4-tetra-hydrocarbazoles has been developed by reaction of 2-aminocyclohexanone hydrochlorides with various phenylhydrazine hydrochlorides via Fischer indole synthesis under mild conditions. The method is more satisfactory in terms of the easy availability of starting materials and the simple one-pot operation.     

Synthesis and Evaluation of Coumarin–Resveratrol Hybrids as 15-Lipoxygenaze Inhibitors

A series of coumarin–resveratrol hybrids, 3-arylcoumarin derivatives 3a–u, were synthesized through the intermolecular condensation reaction of various salicylaldehydes and phenylacetic acids in the presence of 1,4-diazabicyclo[2.2.2]octane under solvent-free conditions. All the synthesized compounds were screened for their inhibitory potency against soybean 15-lipoxygenase. Among them, three compounds (3c, 3j, and 3q) showed good enzyme-inhibitory activities.     

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…     

Sulfamic Acid: Efficient,Cost-Effective Catalyst for Facile Synthesis of Deazaoxaflavin at Ambient Temperature

A facile, ecofriendly procedure has been developed for the synthesis of substituted 5-deaza-10-oxaflavins by sulfamic acid–catalyzed two-component condensation of salicylaldehyde and barbituric acid at ambient temperature. Mild reaction conditions, short reaction time, ambient temperature, ecofriendly solvent system, wide substrate scope, simple workup procedure, no need for chromatographic separation, and good yields are auxiliary advantages of the present protocol.     

Efficient One-Pot Synthesis of Alkyl 2-(Bromomethyl)-2-(4-aryl)-4-alkoxy-5-oxo-2,5-dihydrofuran-3-carboxylate

One-pot, three-component reaction of different phenacyl bromides and dialkylacetylenedicarboxilates was carried out with triphenylphosphine and functionalized oxodihydrofuran derivatives in excellent yields.     

DABCO-促进新型呋喃并[3,2-c]喹啉酮类化合物的合成

在1,4-二氮杂二环[2.2.2]辛烷(DABCO)促进下,以水为反应介质,通过3-溴乙酰基-4-羟基-1-甲基-2-喹啉酮与芳香醛的亲核取代、分子内环化及消除的串联反应,合成了9个新型的呋喃并[3,2-c]喹啉酮类化合物,其结构经~1H NMR,~(13)C NMR,IR,MS(ESI)和元素分析表征。     

An Efficient and Convenient Protocol for the Synthesis of Thiazolidin-4-Ones

Abstract

Without a catalyst and under solvent-free conditions, 2,3-disubstituted-1,3-thiazolidin-4-one 5a–j derivatives were synthesized efficiently via the three-component reaction of aryl hydrazide, aromatic aldehyde, and mercaptoacetic acid. All the newly synthesized compounds were confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy and elemental analysis.

GRAPHICAL ABSTRACT      

Efficient,High-Yield Protocol for the One-Pot Synthesis of Benzopyran Derivatives Catalyzed by p-TSA in Aqueous Media

A short and simple synthesis of benzopyran derivatives was accomplished in good to excellent yields by the reaction of salicylaldehyde with 1,3-cyclohexanediones in aqueous media catalyzed by para-toluenesulfonic acid. The structures were established by spectroscopic data and further confirmed by x-ray analysis. In addition, water was chosen as a green solvent.