scholarly journals Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3+ + 2]-cycloaddition/rearrangement reactions

2018 ◽  
Vol 14 ◽  
pp. 1826-1833 ◽  
Author(s):  
Lin-bo Luan ◽  
Zi-jie Song ◽  
Zhi-ming Li ◽  
Quan-rui Wang
Keyword(s):  
Cycloaddition Reaction ◽  
Ring Expansion ◽  
Aluminium Chloride ◽  
Phenyl Substituent ◽  
Rearrangement Reaction ◽  
Rearrangement Reactions

Two new series of tricyclic heterocycles, namely 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepinium salts 10 and the related neutral, free bases 13 were synthesized from 4-acetoxy-1-acetyl-4-phenylazo-1,2,3,4-tetrahydroquinolines 8 and nitriles 9 in the presence of aluminium chloride by the [3+ + 2]-cycloaddition reaction of the in situ generated azocarbenium intermediates 14 followed by a ring-expansion rearrangement. In the rearrangement reaction, the phenyl substituent in the initially formed spiro-triazolium adducts 16 underwent a [1,2]-migration from C(3) to the electron-deficient N(2). This led to the ring expansion from 6-membered piperidine to 7-membered diazepine furnishing the tricyclic 1,2,4-triazole-fused 1,4-benzodiazepines.

Acid-Catalyzed Ring-expansion of 4-(1-hydroxycyclobutyl)-1,2,3-triazoles

2022 ◽  
Author(s):  
Mingchuan Xu ◽  
Lei Liu ◽  
Tao Wang ◽  
Han Luo ◽  
Meili Hou ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Expansion ◽  
Rearrangement Reaction ◽  
Acid Catalyzed ◽  
Semipinacol Rearrangement

We here reported a direct ring-opening/semipinacol rearrangement reaction of 4-(1-hydroxycyclobutyl)-1,2,3-triazole, in which N-acyl substituted 1,2,3-triazole was generated in situ and would trigger thermodynamically controlled electrocyclization ring-opening to afford rearrangement precursor...

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

2020 ◽  
Author(s):  
Nathan O'Brien ◽  
Naokazu Kano ◽  
Nizam Havare ◽  
Ryohei Uematsu ◽  
Romain Ramozzi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ring Expansion ◽  
Bicyclic Compound ◽  
Compound A ◽  
Ligand System ◽  
Large Bulk ◽  
Rearrangement Reaction ◽  
Hydride Abstraction ◽  
Pentacoordinated Phosphorus ◽  
Acids And Bases

<div>The isolation and reactivities of two pentacoordinated phosphorus–tetracoordinated boron bonded compounds were</div><div>explored. A strong Lewis acidic boron reagent and electron-withdrawing ligand system were required to form the</div><div>pentacoordinated phosphorus state of the P–B bond. The first compound, a phosphoranyl-trihydroborate, gave a THF</div><div>stabilised phosphoranyl-borane intermediate upon a single hydride abstraction in THF. This compound could undergo a</div><div>unique rearrangement reaction, that involved a two-fold ring expansion, to give an unusual fused bicyclic compound or it</div><div>could act as a mono-hydroboration reagent. The hydroboration reactivity of the intermediate was found to be more reactive</div><div>towards alkynes over alkenes with good to moderate regioselectivity towards the terminal carbon. The second compound,</div><div>a phosphoranyl-triarylborate, was found to have a vastly different reactivity to the trihydroborate as it was highly stable</div><div>towards acids and bases. This is thought to be due to the large bulk around the P–B bond as shown in the crystal structure</div>

Ring expansion and ring opening of 3-halooxindoles with N-alkoxycarbonyl-O-tosylhydroxylamines for divergent access to 4-aminoquinolin-2-ones and N-Cbz-N’-arylureas

2021 ◽  
Author(s):  
Wei-Cheng Yuan ◽  
Jian Zuo ◽  
Shu-Pei Yuan ◽  
Jian-Qiang Zhao ◽  
Zhen-Hua Wang ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Expansion

The reaction of N-alkoxycarbonyl-O-tosylhydroxylamines with indol-2-ones in situ generated from 3-halooxindoles has been developed for divergently accessing 4-aminoquinolin-2-ones and N-Cbz-N’-arylureas in good to excellent yields.

Catalyst-Free [2,3]-Sigmatropic Rearrangement Reactions of Photochemically Generated Ammonium Ylides

Synthesis ◽  
2019 ◽  
Vol 51 (23) ◽  
pp. 4348-4358 ◽  
Author(s):  
Fang Li ◽  
Feifei He ◽  
Rene M. Koenigs
Keyword(s):  
Visible Light ◽  
Sigmatropic Rearrangement ◽  
Tertiary Amines ◽  
Amino Esters ◽  
Catalyst Free ◽  
Rearrangement Reaction ◽  
Rearrangement Reactions ◽  
Free Ammonium

The rearrangement reaction of ammonium ylides furnishes valuable α,α-disubstituted amino esters. In this work, we describe the visible-light photolysis reaction of aryldiazoacetates in the presence of tertiary amines that react via a free ammonium ylide in a sigmatropic rearrangement reaction to provide amino esters in moderate to very good yields (33 examples, up to 97% yield).

In situ 1,3-dipolar azide cycloaddition reaction: synthesis of functionalized d-glucose based chiral piperidine and oxazepine analogues

Tetrahedron ◽  
2004 ◽  
Vol 60 (23) ◽  
pp. 4959-4965 ◽  
Author(s):  
Subhankar Tripathi ◽  
Kaushik Singha ◽  
Basudeb Achari ◽  
Sukhendu B Mandal
Keyword(s):  
Cycloaddition Reaction ◽  
Reaction Synthesis

scholarly journals Green ultrasound-assisted three-component click synthesis of novel 1H-1,2,3-triazole carrying benzothiazoles and fluorinated-1,2,4-triazole conjugates and their antimicrobial evaluation

2017 ◽  
Vol 67 (3) ◽  
pp. 309-324 ◽  
Author(s):  
Nadjet Rezki ◽  
Mohamed Reda Aouad
Keyword(s):  
Antimicrobial Activity ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Terminal Alkynes ◽  
One Pot ◽  
Alkyl Aryl ◽  
Antimicrobial Evaluation ◽  
Ultrasound Assisted ◽  
Click Synthesis

AbstractThe present study describes an efficient and ecofriendly, ultrasound, one-pot click cycloaddition approach for the construction of a novel series of 1,4-disubstituted-1,2,3-triazoles tethered with fluorinated 1,2,4-triazole-benzothiazole molecular conjugates. It involved three-component condensation of the appropriate bromoacetamide benzothiazole, sodium azide and 4-alkyl/aryl-5-(2-fluorophenyl)-3-(prop-2-ynylthio)-1,2,4-triazoles4a-ethrough a Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction. This approach involvesin situgeneration of azidoacetamide benzothiazole, followed by condensation with terminal alkynes in the presence of CuSO4/Na-ascorbate in aqueous DMSO under both conventional and ultrasound conditions. Some of the designed 1,2,3-triazole conjugates6a-owere recognized for their antimicrobial activity against some bacterial and fungal pathogenic strains.

Organocatalytic Enantioselective [3+2] Cycloaddition of Azomethine Ylides and Acrolein

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Iratxe Ugarriza ◽  
Uxue Uria ◽  
Efraím Reyes ◽  
Luisa Carrillo ◽  
Jose L. Vicario
Keyword(s):  
Secondary Amine ◽  
Cycloaddition Reaction ◽  
Azomethine Ylides ◽  
Optimum Conditions

AbstractThe [3+2]-cycloaddition reaction between acrolein and in situ generated acyclic azomethine ylides promoted by a chiral secondary amine to generate C-3 unsubstituted pyrrolidines has been studied in detail. Optimum conditions involve the use of the cheap and readily available l-Proline as catalyst to afford the pyrrolidine cycloadduct with complete diastereomeric control and up to 80% enantiomeric control.

Corrigendum to “In situ 1,3-dipolar azide cycloaddition reaction: synthesis of functionalized d-glucose based chiral piperidine and oxazepine analogues”

Tetrahedron ◽  
2005 ◽  
Vol 61 (25) ◽  
pp. 6154
Author(s):  
Subhankar Tripathi ◽  
Kaushik Singha ◽  
Basudeb Achari ◽  
Sukhendu B. Mandal
Keyword(s):  
Cycloaddition Reaction ◽  
Reaction Synthesis

Catecholated graphene-filled polyimide with enhanced mechanical, thermal, and tribological properties

2020 ◽  
pp. 095400832094035
Author(s):  
Xing Wu ◽  
Zhengyu Jin ◽  
Yuejin Zhu ◽  
Haichao Zhao
Keyword(s):  
Friction And Wear ◽  
In Situ Polymerization ◽  
Cycloaddition Reaction ◽  
Mechanical Analysis ◽  
Dipolar Cycloaddition ◽  
Wear Properties ◽  
Comprehensive Properties ◽  
Transmission Electron ◽  
Friction And Wear Tests

In order to achieve good dispersion of graphene in polyimide (PI), catecholated graphene (G-Cat) was prepared by 1,3-dipolar cycloaddition reaction of N-methylglycine and 3,4-dihydroxybenzaldehyde with graphene sheets. G-Cat/PI composites were prepared by in situ polymerization with pyromellitic dianhydride and 4,4-oxydianiline in the presence of G-Cat. The successful modification of graphene was proved by infrared spectroscopy, Raman spectroscopy, and transmission electron microscopy. The comprehensive properties of G-Cat/PI composites were studied by tensile, dynamic mechanical analysis, thermogravimetric analysis, and friction and wear tests. By observing the morphology of wear marks, the friction and wear properties of the composites were emphatically analyzed. Therefore, graphene/PI composites were expected to have broad application prospects in lubrication and wear resistance.

6-Alkynylpurines bearing electronacceptor substituents: Preparation, reactivity in cycloaddition reactions and cytostatic activity

2011 ◽  
Vol 76 (12) ◽  
pp. 1487-1527 ◽  
Author(s):  
Martin Křováček ◽  
Hana Dvořáková ◽  
Ivan Votruba ◽  
Ivana Císařová ◽  
Dalimil Dvořák
Keyword(s):  
Cycloaddition Reaction ◽  
Cytostatic Activity ◽  
Cycloaddition Reactions ◽  
Sonogashira Coupling ◽  
Phenyl Substituent ◽  
Ethynyl Group ◽  
Methyl Propiolate

While direct Sonogashira coupling of 6-halopurines with methyl propiolate and with propargyl aldehyde was not successful, the corresponding orthoester and propargyl aldehyde diethylacetal reacted smoothly. Such prepared orthoester was then converted to the desired methylester by methanolysis, the acetal was too stable to be hydrolyzed. The obtained 6-ethynylpurines, bearing orthoester, acetal, methoxycarbonyl and for comparison also the phenyl substituent on the ethynyl group, were subjected to the cycloaddition reaction with cyclopentadiene, diazomethane and phenylazide. Electron deficient alkynylpurines were considerably more reactive in this reaction compared to the not activated phenylethynyl derivative. The prepared alkynylpurines exhibited medium cytostatic activity (IC50 = 2.6–15 μM), while the cycloadducts were inactive.

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