One-pot synthesis of quinoline-based tetracycles by a tandem three-component reaction

A practical one-pot synthetic strategy for the efficient synthesis of a range of structurally interesting and bioactive quinoline-based tetracycles has been developed. A key step in the synthesis is a tandem three-component reaction of heteroaromatic amine, methyl 2-formylbenzoate and (t)butyl isonitrile, followed by TFA-mediated lactamization via intramolecular aminolysis of an adjacent ester. Results related to a kinase-panel screening for several selected compounds are also discussed in this article.     

One-pot three-component tandem metathesis/Diels-Alder reaction

[reaction: see text] A tandem enyne, diene-ene metathesis reaction followed by Diels-Alder reaction accomplished a stereoselective three-component reaction protocol with four stereocenters.     

One-pot three-component synthesis of the spiroacenaphthylene derivatives

A facile and efficient one-pot three-component synthesis of the spiroacenaphthylene derivatives was achieved, via the reaction of acenaphthequinone, malononitrile/ethylcyanoacetate and various reagents including α-methylencarbonyl compounds/enols.     

One-pot synthesis of macrocycles by a tandem three-component reaction and intramolecular [3+2] cycloaddition

By combining three appropriately designed simple substrates, a programmed sequence involving an alpha-isocyano acetamide-based three-component reaction followed by a copper-catalyzed intramolecular [3+2] cycloaddition of alkyne and azide took place to afford complex macrocycles in moderate to good yields. One macrocycle and two heterocycles were produced with concurrent formation of five chemical bonds in this operationally simple process.     

One-pot copper-catalyzed synthesis of N-functionalized pyrazoles from boronic acids

A straight-forward route to prepare a diverse set of N-aryl pyrazoles via a one-pot copper-catalyzed boronic acid coupling and cyclization protocol is presented. A variety of aryl and heteroaryl N-functionalized pyrazoles not easily accessible by other means were formed in good yield from readily available boronic acid precursors in an operationally simple procedure.     

One-pot synthesis of 5-(substituted-amino)pyrazoles

An efficient and mild one-pot synthesis of substituted 5-alkylamino and/or 5-(arylamino)pyrazoles is described. A suitably decorated β-ketoamide, an aryl or alkyl hydrazine and Lawesson's reagent are suspended in THF/Py and gently heated to yield the requisite 5-aminopyrazoles.     

One-pot synthesis of tetrahydrofuran derivatives via a divalent palladium-catalyzed three-component coupling

Under divalent palladium catalysis, a three-component coupling reaction for synthesizing tetrahydrofuran derivatives has been established. The reaction involves the intramolecular carbopalladation of an alkyne with a carbanion which was generated from the addition of an alkoxide ion to an alkene derivative, followed by allylic chloride insertion to the CPd bond and quenching the CPd bond by β-heteroatom elimination in the presence of excess chloride ions.     

One-pot three-component green synthesis of novel dihydrophthalazine-1,4-diones

Green and efficient one-pot three-component synthesis of novel 2-(7-amino-2,2-dimethyl-4-oxo-5-phenyl-4,5-dihydropyrano[2,3-d][1,3]dioxin-6-ylcarbonyl)-2,3-dihydrophthalazine-1,4-diones have been developed by condensing 3-(1,4-dioxo-1,2,3,4-tetrahydrophthalazin-2-yl)-3-oxopropanenitrile with benzaldehydes and Meldrum’s acid using L-proline as catalyst in ethanol at room temperature. The products have been isolated as pure compounds in good yields without using column chromatography.     

One-pot three-component protocol for the synthesis of substituted 2-aminothiazoles

Substituted 2-aminothiazoles have been synthesized from α-nitro-epoxides, cyanamide, and sodium sulfide through a facile, three-component, and ecofriendly protocol with good to excellent yields. This reaction was achieved at room temperature without any additives. A possible mechanism has also been proposed.     

A novel synthesis of 1,3,5-trisubstituted pyrazoles through a spiro-pyrazoline intermediate via a tandem 1,3-dipolar cycloaddition/elimination

The syntheses of an important class of hitherto unreported 1,3,5-pyrazoles, inspired by an unanticipated eliminatory ring opening are described. The reported pyrazole compounds were constructed through the Huisgen cyclization of 2-methylene-1,3,3-trimethylindoline and an in situ generated nitrile imine. The newly formed spiro-pyrazoline intermediate presumably then undergoes a ring opening/elimination process to afford a pyrazole, as evidenced by single X-ray crystal data. The current report constitutes the first formal observation of this kind of ring opening involving a spiro-pyrazoline intermediate.     

A novel one-pot, three-component reaction for the synthesis of isocoumarin-condensed pyrazoles

The one-pot, three-component reaction of substituted homophthalic anhydrides with hydrazine in DMF as solvent and reactant, at reflux temperature, afforded isochromeno[3,4-c]pyrazole-5(2H)-one derivatives in high yields. The mechanism and roles of the substrates were investigated and it was found that cyclic hydrazides were formed as intermediates.     

One-pot three-component synthesis, structure and redox properties of ferrocenyl isoxazoles

A consecutive coupling-cycloaddition sequence of acid chlorides, terminal alkynes, and in situ generated nitrile oxides furnishes ferrocenyl substituted redox active isoxazoles in moderate to good yields. The structure was unambiguously assigned by X-ray structure analyses and the electronic structure was elucidated by computational methods. Redox potentials of all representatives are strongly effected by the electronic nature of the bridging isoxazoloyl moiety.     

One-pot tandem Barbier-Prins synthesis of tetrahydropyrans in aqueous media

Tetrahydropyran is an important structural core ofmany carbohydrates and their polymers. Its structure ispresent in numerous natural compounds such as poly-ether antibiotics, marine toxins and pheromones[1,2].Thus many reactions have been developed toward…     

One-pot synthesis of trifluoromethyl- and nitroso-substituted pyrazolines and pyrazoles and their tuberculostatic activity

3-Trifluoromethyl-substituted 4-nitrosopyrazolines and 4-nitrosopyrazoles were prepared by a one-pot synthesis from trifluoromethyl-containing 1,3-diketones, sodium nitrite in acetic acid, and hydrazines (hydrazine hydrate, methylhydrazine). 3-Trifluoromethylpyrazolines can be converted to pyrazoles on heating. The use of phenylhydrazine in these reactions led to the formation of regioisomeric 4-hydroxyimino-5-(trifluoromethyl)pyrazoline. The structure of heterocycles synthesized was established using X-ray diffraction study, ¹H and ¹⁹F NMR spectroscopy. The obtained products exhibited considerable tuberculostatic activity.     

One-pot three-component synthesis of alpha-iminonitriles by IBX/TBAB-mediated oxidative Strecker reaction

The reaction of aldehydes, amines, and TMSCN in the presence of 2-iodoxybenzoic acid (IBX) and tetrabutylammonium bromide (TBAB) afforded alpha-iminonitriles in good to excellent yields under mild conditions. The presence of TBAB is essential for this transformation. The methodology was applied to a two-step synthesis of indolizidine via a microwave-assisted intramolecular cycloaddition of alpha-iminonitrile.     

One-pot, three-component synthesis of secondary amines and trisubstituted hydrazines from ketones

Various imines and hydrazones were reduced to the corresponding amines and hydrazines using borane-tetrahydrofuran complex as a reducing agent in the solution of lithium perchlorate in diethyl ether. The initial imines or hydrazones have been prepared at the same conditions just before the reduction step. Both steps were carried out in one vessel with a good yield and insignificant formation of by-products.