Synthesis of 1,2,4-Oxadiazoles by Tandem Reaction of Nitroalkenes with Arenes and Nitriles in the Superacid TfOH

Golushko, Andrei; Khoroshilova, Olesya V.; Vasilyev, Aleksander V.

doi:10.1021/acs.joc.9b00812

Cited by 20 publications

(7 citation statements)

References 33 publications

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“…Owing to the diverse applications of oxadiazole derivatives in pharmaceutical chemistry, [1] this class of five-membered heterocycles has been a subject of interest for synthetic organic chemists. [2][3][4][5][6][7][8] Amongst the four isomers (1-4) associated with the oxadiazole skeleton (Scheme 1), the biological activity of 1,2,4-oxadiazole ring 2 was identified in the early 1940s, although the synthesis dates back to 1884 by Tiemann and Kruger. [9] Commercial drugs with the 1,2,4-oxadiazole 2 core were introduced as cough suppressants [10][11][12] and subsequently the anticancer, anti-inflammatory, antiparasitic, antiviral, antibacterial, antidepressant, analgesic and anticonvulsant properties were discovered in the last 40 years (Scheme 2).…”

Section: Introductionmentioning

confidence: 99%

“…In 2003, Bokach et al [2] used platinum (IV) catalyst for these 32CA reactions and in 2017, the reactions of amidoximes and carboxylic acid esters in the superbase medium were reported to yield 3,5-disubstituted-1,2,4-oxadiazoles. [4] Recently, the reaction of amidoximes with gem-dibromomethylarene were performed by Vinaya K. et al, [6] and Golushko et al [7] have reported the tandem reactions of nitroalkenes with nitriles in TfOH to synthesise these heterocycles.…”

Section: Introductionmentioning

confidence: 99%

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Unveiling the Chemo‐ and Regioselectivity of the [3+2] Cycloaddition Reaction between 4‐Chlorobenzonitrile Oxide and β‐Aminocinnamonitrile with a MEDT Perspective**

Domingo

Acharjee

2021

ChemistrySelect

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A molecular electron density theory (MEDT) study for the [3 + 2] cycloaddition (32CA) reaction of 4-chlorobenzonitrile oxide (CBNO) and β-aminocinnamonitrile (ACN) has been performed at the MPWB1K/6-311G(d,p) computational level. This 32CA reaction, characterised as the zwitterionic type (zw-type), presents an activation enthalpy of 11.8, 14.2 and 16.6 kcal mol À 1 , in gas phase, benzene and methanol. The formation of 3-aryl-5-(β-aminostyryl)-1,2,4-oxadiazole is predicted as the energetically feasible one following a nonconcerted two-stage one-step mechanism. This zw-type 32CA reaction shows a total chemo and regioselectivity. The global electron density transfer at the most favourable transition state structure (TS), higher than 0.14 e, suggests some polar character. The most energetically favoured TS shows an intramolecular hydrogen bond between the amine À NH 2 of ACN and the oxygen of CBNO, which favours this zw-type 32CA reaction. This behaviour is enhanced with the inclusion of a methanol molecule hydrogen bonded to this oxygen atom. The present MEDT study suggests that the best experimental conditions are to use a non-polar solvent such as benzene containing catalytic amounts of a protic solvent such as methanol.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Unveiling the Chemo‐ and Regioselectivity of the [3+2] Cycloaddition Reaction between 4‐Chlorobenzonitrile Oxide and β‐Aminocinnamonitrile with a MEDT Perspective**

Domingo

Acharjee

2021

ChemistrySelect

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“…For the synthesis of vinyl-1,2,4-oxadiazole 1d we adapted the protocol described by Golushko and co-workers in which benzonitrile was replaced by acrylonitrile. 24,25 This resulted in 3-(diphenylmethyl)-5-ethenyl-1,2,4-oxadiazole (1d) at 63% yield, after purification by column chromatography (Scheme 2).…”

Section: Cluster Syn Lettmentioning

confidence: 99%

Aza-Morita–Baylis–Hillman Reaction with Vinyl-oxadiazoles: An Expeditious Approach to Access New Heterocyclic Arrangements

Capretz-Agy¹,

Fernandes²,

Rodrigues³

et al. 2019

Synlett

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In this communication, we disclosed a new aza-MBH reaction in which traditional nucleophilic partners of these reactions (e.g., acrylates, nitroolefins or enones) were replaced by vinyl-1,2,4-oxadiazoles. Thus, the aza-MBH reaction between 5-aryl-3-vinyl-1,2,4-oxadiazoles and N-sulfonylimines, catalyzed by the mixture DABCO/AcOH, provides a class of new adduct in yields varying from 31% up to 93% in reaction times from 30 minutes to 24 hours. Due to the biological activities and technological applications associated with the 1,2,4-oxadiazole motifs, this new class of heterocycles offers great synthetic and commercial potentiality.

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“…TNP can be characterized by a very reactive structure for organic synthesis and the ability to insert different CX 3 and NO 2 groups into the main product, which additionally stimulates many important biologically active functions [ 24 , 25 , 26 , 27 , 28 ]. Moreover, this nitroalkene was successfully tested in 32CA reactions with many organic compounds, such as nitrones [ 29 , 30 , 31 ], nitrile N -oxides [ 32 , 33 ], diazocompounds [ 2 , 3 , 34 ] and N -azomethine ylides [ 35 , 36 , 37 ], and in other reactions [ 38 , 39 , 40 ]. In turn, to model the three-atom component (TAC) [ 23 ], we decided to use N -(4-bromophenyl)-C-phenylnitrylimine (NI) ( 2a ).…”

Section: Introductionmentioning

confidence: 99%

On the Question of the Formation of Nitro-Functionalized 2,4-Pyrazole Analogs on the Basis of Nitrylimine Molecular Systems and 3,3,3-Trichloro-1-Nitroprop-1-Ene

et al. 2022

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Experimental and theoretical studies on the reaction between (E)-3,3,3-trichloro-1-nitroprop-1-ene and N-(4-bromophenyl)-C-arylnitrylimine were performed. It was found that the title process unexpectedly led to 1-(4-bromophenyl)-3-phenyl-5-nitropyrazole instead of the expected Δ2-pyrazoline molecular system. This was the result of a unique CHCl3 elimination process. The observed mechanism of transformation was explained in the framework of the molecular electron density theory (MEDT). The theoretical results showed that both of the possible channels of [3 + 2] cycloaddition were favorable from a kinetic point of view, due to which the creation of 1-(4-bromophenyl)-3-aryl-4-tricholomethyl-5-nitro-Δ2-pyrazoline was more probable. On the other hand, according to the experimental data, the presented reactions occurred with full regioselectivity.

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Synthesis of 1,2,4-Oxadiazoles by Tandem Reaction of Nitroalkenes with Arenes and Nitriles in the Superacid TfOH

Cited by 20 publications

References 33 publications

Unveiling the Chemo‐ and Regioselectivity of the [3+2] Cycloaddition Reaction between 4‐Chlorobenzonitrile Oxide and β‐Aminocinnamonitrile with a MEDT Perspective**

Unveiling the Chemo‐ and Regioselectivity of the [3+2] Cycloaddition Reaction between 4‐Chlorobenzonitrile Oxide and β‐Aminocinnamonitrile with a MEDT Perspective**

Aza-Morita–Baylis–Hillman Reaction with Vinyl-oxadiazoles: An Expeditious Approach to Access New Heterocyclic Arrangements

On the Question of the Formation of Nitro-Functionalized 2,4-Pyrazole Analogs on the Basis of Nitrylimine Molecular Systems and 3,3,3-Trichloro-1-Nitroprop-1-Ene

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