Regioselection in 1,3-Dipolar Cycloadditions of 3-Methylpyridine N-Imide to Aromatic Carbonitriles. Synthesis of 2-Aryl-8-Methyl[1,2,4]Triazolo [1,5-a]Pyridines

2002 ◽  
Vol 2002 (11) ◽  
pp. 560-561 ◽  
Author(s):  
Zhang Guolin ◽  
Hu Yongzhou
Keyword(s):  
Potassium Hydroxide ◽  
Dipolar Cycloaddition ◽  
Aromatic Nitriles ◽  
Dipolar Cycloadditions

1-Amino-3-methylpyridinium mesitylenesulfonate (3) reacts with aromatic nitriles in the presence of potassium hydroxide, undergoing 1,3-dipolar cycloaddition followed by elimination of H2 to give 2-aryl-8-methyl[1,2,4]triazolo[1,5- a]pyridines as the major products, rather than the 6-methyl isomers.

1,3-Dipolar cycloadditions of Arylcarbonitrile Oxides and Diaryl Nitrilimines with Some 2-Arylmethylene-1,3-Indanediones; regiochemistry of the Reactions

2003 ◽  
Vol 2003 (4) ◽  
pp. 204-207 ◽  
Author(s):  
Sarra Boudriga ◽  
Mohiedinne Askri ◽  
Rafik Gharbi ◽  
Mohamed Rammah ◽  
Kabula Ciamala
Keyword(s):  
Ring Closure ◽  
Dipolar Cycloaddition ◽  
Dipolar Cycloadditions

Ring-closure reaction affording spiroisoxazolines and spiropyrazolines via a 1,3-dipolar cycloaddition between the title compounds, occurs with high regioselectivity.

The 1,3-Dipolar Cycloaddition Reactions of Nitrile Oxides in Water Media

2021 ◽  
Vol 25 ◽  
Author(s):  
Joaquín Plumet
Keyword(s):  
Carbonyl Compounds ◽  
Critical Discussion ◽  
Aldol Reactions ◽  
Dipolar Cycloaddition ◽  
Hydroxy Ketone ◽  
Unsaturated Ketones ◽  
Dipolar Cycloadditions ◽  
Nitrile Oxides ◽  
Water Media ◽  
Synthetic Intermediates

: The 1,3-dipolar cycloadditions (DCs) of nitrile oxides (NOs) have been used as a powerful tool in synthetic organic chemistry. The cycloadducts arising from cycloadditions (CAs) of NOs to alkenes and alkynes (2-isoxazolines and isoxazoles respectively) are valuable synthetic intermediates because, among others, their capacity to mask other functionalities including α, β-unsaturated ketones, β-hydroxy carbonyl compounds and 1,3-aminoalcohols. In particular, the β-hydroxy ketone functionality is an illustrative example, making the NOs alkenes CAs reactions a synthetically equivalent methodology of aldol reactions. The vast majority of these reactions are carried out in organic solvents. Nevertheless, the use of water as an alternative solvent has evident advantages on the “Green Chemistry” concept. The critical discussion on the use of water instead of “conventional” solvents in the 1,3-DCs reactions of NOs is the objective of the present review.

scholarly journals Dipolar cycloadditions of HMF-based nitrones: stepwise and multicomponent reactions, stereochemical outcome and structural scope

2020 ◽  
Vol 22 (22) ◽  
pp. 7907-7912
Author(s):  
Lianjie Wang ◽  
Charlie Verrier ◽  
Mohammed Ahmar ◽  
Yves Queneau
Keyword(s):  
Multicomponent Reactions ◽  
Dipolar Cycloaddition ◽  
Dipolar Cycloadditions

The straightforward preparation of new 3-furanyl isoxazolidines by 1,3-dipolar cycloaddition of 5-hydroxymetylfurfural (HMF)-derived nitrones with electro-deficient olefins is investigated.

1,3-Dipolar Cycloadditions of a Chiral Oxazolidinone With Nitrones and Nitrile Oxides

1995 ◽  
Vol 48 (9) ◽  
pp. 1511 ◽  
Author(s):  
SG Pyne ◽  
J Safaei-G ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Hydrogen Atmosphere ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
The Novel ◽  
X Ray ◽  
Dipolar Cycloadditions ◽  
Nitrile Oxides ◽  
Exocyclic Methylene

The 1,3-dipolar cycloaddition reactions of the chiral oxazolidinone (1) and nitrones are highly regioselective and only 5,5-disubstituted isoxazolidine adducts are formed. These reactions occur under equilibrating conditions to give the more stable adducts that result from addition to the exocyclic methylene of (1) from the sterically more hindered π-face. The endo adducts are generally thermodynamically favoured. In one case the novel azetidine (21) was formed from the treatment of the adduct (4a) with palladium hydroxide on carbon under a hydrogen atmosphere. The major adducts from the reaction of (1) and nitrile oxides (16a,b) had the expected stereochemistry, addition of the 1,3-dipole having occurred from the less hindered π-face of the exocyclic methylene of (1). The stereochemistry of many of these products has been elucidated by single-crystal X-ray structural determinations.

Improved Protocols for Microwave-Assisted Cu(I)-Catalyzed Huisgen 1,3-Dipolar Cycloadditions

2007 ◽  
Vol 72 (8) ◽  
pp. 1014-1024 ◽  
Author(s):  
Pedro Cintas ◽  
Katia Martina ◽  
Bruna Robaldo ◽  
Davide Garella ◽  
Luisa Boffa ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Microwave Irradiation ◽  
Ultrasound Irradiation ◽  
Conventional Heating ◽  
Dipolar Cycloaddition ◽  
One Pot ◽  
Click Reactions ◽  
Dipolar Cycloadditions ◽  
Microwave Assisted ◽  
New Applications

The Huisgen 1,3-dipolar cycloaddition of azides and acetylenes catalyzed by Cu(I) salts, leading to 1,2,3-triazoles, is one of the most versatile "click reactions". We have developed a series of optimized protocols and new applications of this reaction starting from several substrates, comparing heterogeneous vs homogeneous catalysis, conventional heating vs microwave irradiation or simultaneous microwave/ultrasound irradiation. Both non-conventional techniques strongly promoted the cycloaddition (bromide → azide → triazole), that could be conveniently performed in a one-pot procedure. This was feasible even with such bulky molecules as functionalized β-cyclodextrins (β-CD), starting from 61-O-tosyl-β-CD or from heptakis[6-O-(tert-butyldimethylsilyl)]-21-O-propargyl-β-CD. "Greener" heterogeneous catalysis with charcoal-supported Cu(II) or Cu(I) (prepared under ultrasound) was advantageously employed.

Cross 1,3-dipolar cycloadditions of C,N-cyclic azomethine imines with an N-benzyl azomethine ylide: facile access to fused tricyclic 1,2,4-hexahydrotriazines

2019 ◽  
Vol 17 (2) ◽  
pp. 244-247 ◽  
Author(s):  
Kai-Kai Wang ◽  
Yan-Li Li ◽  
Zhan-Yong Wang ◽  
Meng-Wei Hu ◽  
Ting-Ting Qiu ◽  
...  
Keyword(s):  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
Dipolar Cycloadditions ◽  
Azomethine Imines

A cross 1,3-dipolar cycloaddition of two different ylides between C,N-cyclic azomethine imines with an in situ generated non-stabilized azomethine ylide from an N-benzyl precursor is reported.

scholarly journals Multilayer graphene functionalized through thermal 1,3-dipolar cycloadditions with imino esters: a versatile platform for supported ligands in catalysis

2019 ◽  
Vol 55 (52) ◽  
pp. 7462-7465 ◽  
Author(s):  
Marcos Ferrándiz-Saperas ◽  
Alessio Ghisolfi ◽  
Diego Cazorla-Amorós ◽  
Carmen Nájera ◽  
José M. Sansano
Keyword(s):  
Azomethine Ylides ◽  
Dipolar Cycloaddition ◽  
Multilayer Graphene ◽  
Dipolar Cycloadditions ◽  
Chelating Ligand ◽  
Imino Esters

Multilayer graphene (MLG), obtained by mild sonication of graphite, was functionalized via 1,3-dipolar cycloaddition with azomethine ylides and used as a heterogeneous N,O-chelating ligand to coordinate iridium atomic centers.

scholarly journals Huisgen [3 + 2] Dipolar Cycloadditions of Phthalazinium Ylides to Activated Symmetric and Non-Symmetric Alkynes

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4416
Author(s):  
Vasilichia Antoci ◽  
Costel Moldoveanu ◽  
Ramona Danac ◽  
Violeta Mangalagiu ◽  
Gheorghita Zbancioc
Keyword(s):  
Reaction Time ◽  
Comparative Study ◽  
Cycloaddition Reaction ◽  
Environmentally Friendly ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Dimethyl Acetylenedicarboxylate ◽  
Thermal Heating ◽  
Dipolar Cycloadditions ◽  
Methyl Propiolate

We present herein a straightforward and efficient pathway for the synthesis of pyrrolophthalazine cycloadducts via Huisgen [3 + 2] dipolar cycloaddition reactions of phthalazinium ylides to methyl propiolate or dimethyl acetylenedicarboxylate (DMAD). A thoroughly comparative study concerning the efficiency of synthesis, conventional thermal heating (TH) versus microwave (MW) and ultrasound (US) irradiation, has been performed. The cycloaddition reactions of phthalazinium ylides to methyl propiolate occur regiospecific, with a single regioisomer being obtained. Under conventional TH, the cycloaddition reaction of phthalazinium ylides with DMAD occurs to a mixture of inseparable partial and fully aromatized pyrrolophthalazine cycloadducts, while MW or US irradiation are leading only to fully aromatized compounds, with the reactions becoming selective. A feasible mechanism for formation of fully aromatized compounds is presented. Besides selectivity, it has to be noticed that the reaction setup under MW or US irradiation offer a number of other certain advantages: higher yields, decreasing of the amount of used solvent comparative with TH, decreasing of the reaction time from hours to minutes and decreasing of the consumed energy; consequently, these reactions could be considered environmentally friendly.

1,3-Dipolar cycloadditions of nitrile oxides with 7-oxa- and 7-azabenzonorbornadienes

2014 ◽  
Vol 92 (7) ◽  
pp. 635-639 ◽  
Author(s):  
Jaipal R. Nagireddy ◽  
Emily Carlson ◽  
William Tam
Keyword(s):  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Biological Testing ◽  
Dipolar Cycloadditions ◽  
Nitrile Oxides ◽  
Anti Cancer ◽  
Efficient Construction ◽  
Cancer Activity

Dipolar cycloaddition reactions allow for the efficient construction of five-membered heterocycles, often with diverse medicinal applications. We examined the 1,3-dipolar cycloaddition of 7-oxabenzonorbornadienes and 7-azabenzonorbornadienes with acetonitrile oxide and benzonitrile oxide, achieving an assortment of heterobicycle-fused isoxazolines with good to excellent yields. All isoxazolines were consistently directed to the exo face of the bicyclic framework with complete stereoselectivity. Preliminary biological testing of the adducts also showed positive anti-cancer activity, suggesting their potential pharmaceutical utility.

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