Synthesis of N-Alkyl-2-aryl-5H-imidazo[1,2-b]pyrazol-3-amines by a Three-Component Condensation Reaction

Rahmati, Abbas; Kouzehrash, Meysam Alizadeh

doi:10.1055/s-0030-1260154

Cited by 33 publications

(9 citation statements)

References 5 publications

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“…[12,32] Classically, the Ugi-type reactions require a carboxylic acid as mentioned above. Toward the synthesis of heterocycles utilizing isocyanide, our concept of the carboxylic acid free Ugi-type reaction was [33] Based on this hypothesis, we chose the N′-acyl azomethine imine structure as an "isocyanophile", [34] which is an extended conjugated 1,3-dipole and could function as a "1,5-dipole" to afford the corresponding heterocycles (Scheme 10, lower). [35] At first, we examined whether the N′-acyl azomethine imine could act as a 1,5-dipolar equivalent, which can trap an isocyanide as a C1 source to afford the corresponding imin-1,3,4-oxadiazin-6-one derivatives.…”

Section: Novel [5+1] Cycloaddition Reaction Of Cn-cyclic N′-acyl Azomentioning

confidence: 99%

Carboxylic Acid Free Novel Isocyanide‐Based Reactions

Soeta

Ukaji

2014

The Chemical Record

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In order to develop a practical method for the construction of drug-like and heterocyclic compounds, we have designed a novel Passerini- or Ugi-type reaction system where a compound (which we write in the general form as Z-X) composed of an electrophilic (Z) and a nucleophilic group (X) could essentially perform the same function as the carboxylic acid. Based on this concept, we have developed the O-silylative Passerini reaction and the borinic acid catalyzed α-addition of isocyanides to aldehydes and water. In addition, we have designed and demonstrated the addition reaction of isocyanides to nitrones in the presence of TMSCl to afford the corresponding 1,2,3,4-tetrahydroisoquinoline-1-carboxyamides. Furthermore, a novel [5 + 1] cycloaddition of isocyanide was explored with C,N-cyclic N'-acyl azomethine imines as a "1,5-dipole" via a strategy involving intramolecular trapping of the isocyanide.

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Section: Novel [5+1] Cycloaddition Reaction Of Cn-cyclic N′-acyl Azomentioning

confidence: 99%

Carboxylic Acid Free Novel Isocyanide‐Based Reactions

Soeta

Ukaji

2014

The Chemical Record

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“…Several publications deal with 2-amino-1,3,4-thiadiazoles [71,83–84 89–90], 2-aminoimidazoles [71–72 91–92], 2-aminoxazoles [71] and 1,2,5-oxadiazole-3,4-diamine [93] with the formation of imidazoazoles. Among the pyrazoles only 5-amino-3-methylpyrazole, 5-aminopyrazole-4-carbonitrile and ethyl 5-aminopyrazole-4-carboxylate are described in GBB-3CR [29,71,83–84 94–96]. To the best of our knowledge, there is no information about the reactivity of aminoazoles as an amine component in Ugi-4CR.…”

Section: Introductionmentioning

confidence: 99%

New tricks of well-known aminoazoles in isocyanide-based multicomponent reactions and antibacterial activity of the compounds synthesized

Murlykina

Kornet

Десенко

et al. 2017

Beilstein J. Org. Chem.

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The well-known aminoazoles, 3-amino-5-methylisoxazole and 5-amino-N-aryl-1H-pyrazole-4-carboxamides, were studied as an amine component in Ugi and Groebke–Blackburn–Bienaymé multicomponent reactions. The first example of an application of aminoazoles in an Ugi four-component reaction was discovered and novel features of a Groebke–Blackburn–Bienaymé cyclocondensation are established and discussed. The heterocycles obtained were evaluated for their antibacterial activity and several of them demonstrated a weak antimicrobial effect, but for most of the compounds a 30–50% increase in biomass of Gram-positive strains (mainly B. subtilis) compared to control was observed.

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“…In the relevant literature [7,28–29 31–33], the products have predominantly been described as 5 H -imidazo[1,2- b ]pyrazoles with an endo double bond (and not as 1 H -imidazo[1,2- b ]pyrazoles), but without 2D NMR-based support. However, the GBB-3CR of functionalized pyrazoles might lead to the formation of two regioisomers [24] and four different tautomeric forms (5 H - or 1 H -imidazo[1,2- b ]pyrazole with an endo- or exocyclic double bond) of each regioisomer.…”

Section: Introductionmentioning

confidence: 99%

Facile synthesis of 1H-imidazo[1,2-b]pyrazoles via a sequential one-pot synthetic approach

Demjén¹,

Gyuris²,

Wölfling³

et al. 2014

Beilstein J. Org. Chem.

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Summary5-Aminopyrazole-4-carbonitrile and ethyl 5-aminopyrazole-4-carboxylate, as potential trifunctional building blocks are introduced in a facile, chemo- and regioselective multicomponent assembly of imidazo[1,2-b]pyrazoles via the Groebke–Blackburn–Bienaymé reaction (GBB reaction). Besides the synthetic elaboration of a green-compatible isocyanide-based access in three-component mode, we describe an operationally simple, one-pot two-step GBB protocol for the rapid construction of a 46 membered imidazo[1,2-b]pyrazole library with yields up to 83%.

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Synthesis of N-Alkyl-2-aryl-5H-imidazo[1,2-b]pyrazol-3-amines by a Three-Component Condensation Reaction

Cited by 33 publications

References 5 publications

Carboxylic Acid Free Novel Isocyanide‐Based Reactions

Carboxylic Acid Free Novel Isocyanide‐Based Reactions

New tricks of well-known aminoazoles in isocyanide-based multicomponent reactions and antibacterial activity of the compounds synthesized

Facile synthesis of 1H-imidazo[1,2-b]pyrazoles via a sequential one-pot synthetic approach

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