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

Synlett ◽  
2019 ◽  
Vol 31 (06) ◽  
pp. 622-626
Author(s):  
André Capretz-Agy ◽  
Fábio S. Fernandes ◽  
Manoel T. Rodrigues ◽  
Caroline Conti ◽  
Fernando Coelho
Keyword(s):  
Biological Activities ◽  
Reaction Times ◽  
New Class ◽  
Mbh Reaction

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.

Anodyne activities of New Tetrazole derivatives from Triazine

2020 ◽  
Vol 11 (3) ◽  
pp. 3377-3383
Author(s):  
Arulmozhi R ◽  
Abirami N ◽  
Helen P Kavitha ◽  
Arulmurugan S ◽  
Vinoth Kumar J
Keyword(s):  
Heterocyclic Compounds ◽  
Biological Activities ◽  
Pharmaceutical Chemistry ◽  
Tail Flick ◽  
Structural Fragment ◽  
Hot Plate ◽  
Standard Drug ◽  
New Class ◽  
Novel Drugs ◽  
Tetrazole Derivatives

The creation of novel drugs containing a tetrazole ring as a structural fragment has contributed considerably to the outstanding achievements of the pharmaceutical chemistry in the last decade. Tetrazoles are the heterocyclic compounds having diverse biological activities such as analgesic, antiinflammation, antimicrobial, anticancer, antidiabetic, etc., and an impending source in biosciences. In this paper, the authors describe the synthesis of novel tetrazoles from N, N-( 6-Phenyl-1,3,5-triazine-2,4-diyl) dibenzamide (PTDDB) and 2-phenyl-4, 6-di(2H-tetrazole-2-yl)-1,3,5-triazine(5a-i) were prepared per the proposed scheme. A new class of tetrazole heterocycles were synthesised and characterised. I n vivo analysis was carried out on the analgesic property of synthesised tetrazole derivatives (5a, 5b, 5c). Characterisation studies such as IR, 1H NMR, 13C NMR, Mass and elemental analysis were performed for the synthesised tetrazole derivatives. Some of the tetrazole derivatives 5a, 5b, and 5c were tested for anodyne activity using morphine as the standard drug. The data reveals that all the three compounds 5a, 5b and 5c taken for the study show analgesic activity by hot plate method and tail flick methods. Among tested compounds, compound 5c is found to have potent analgesic (anodyne) activity. The results of the study indicate that the sample taken for the study show fairly good business using morphine as the standard drug.

Regioselective Synthesis of Potent 4,5,6,7-Tetrahydroindazole Derivatives via Microwave-assisted Vilsmeier-Haack Reaction and their Antioxidant Activity Evaluation

2019 ◽  
Vol 16 (3) ◽  
pp. 194-201 ◽  
Author(s):  
Renu Bala ◽  
Vandana Devi ◽  
Pratibha Singh ◽  
Navjot Kaur ◽  
Pawandeep Kaur ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Microwave Irradiation ◽  
Biological Activities ◽  
Reaction Times ◽  
Conventional Heating ◽  
High Chemical ◽  
Microwave Assisted ◽  
Work Up ◽  
Active Methylene ◽  
By Products

Background: Tetrahydroindazole, a member of the fused-pyrazole system, is a least studied class of heterocyclic compounds owing to its scarcity in nature. However, a large number of synthetically prepared tetrahydroindazoles are known to show a variety of biological activities such as interleukin- 2 inducible T-Cell kinase inhibitors, AMPA receptor positive allosteric modulators, antitumor, antituberculosis, anti-inflammatory and antimicrobial activities. Vilsmeier-Haack reaction is one of the most important chemical reactions used for formylation of electron rich arenes. Even though Vilsmeier- Haack reaction was studied on a wide variety of hydrazones derived from active methylene compounds, literature lacks the examples of the use of 4-substituted cyclohexanones as a substrate for the synthesis of 4,5,6,7-tetrahydroindazoles. The study of the reaction of Vilsmeier-Haack reagent with hydrazones derived from cyclic keto compounds having active methylene has been considered the interested topic of investigation. In the present study, ethyl cyclohexanone-4-carboxylate was treated with one equivalent of various hydrazines for two hours and the resulted hydrazones were further treated with an OPC-VH reagent (Vilsmeier-Haack reagent isolated from phthaloyl dichloride and N,Ndimethylformamide) afforded 4,5,6,7-tetrahydroindazoles in excellent yields. The synthesized compounds 4a-f and 5a-f were screened for their antioxidant activities using the DPPH radical scavenging assay. The target compounds were synthesized regioselectively using 4+1 approach in excellent yields. A number of experiments using both conventional heating as well as microwave irradiation methods were tried and on comparison, microwave irradiation method was found excellent in terms of easy work up, high chemical yields, shortened reaction times, clean and, no by-products formation. Some of the synthesized compounds showed significant antioxidant activity. The microwave assisted synthesis of 4,5,6,7-tetrahydroindazoles from ethyl cyclohexanone-4-carboxylate has been reported under mild conditions in excellent yield. Easy work up, high chemical yield, shortened reaction times, clean and no by-products formation are the major advantages of this protocol. These advantages may make this method useful for chemists who are interested in developing novel 4,5,6,7-tetrahydroindazole based drugs.

Advances in Triazole Synthesis from Copper-catalyzed Azide-alkyne Cycloadditions (CuAAC) Based on Eco-friendly Procedures

2019 ◽  
Vol 16 (2) ◽  
pp. 244-257 ◽  
Author(s):  
Marcus Vinicius Nora de Souza ◽  
Cristiane França da Costa ◽  
Victor Facchinetti ◽  
Claudia Regina Brandão Gomes ◽  
Paula Mázala Pacheco
Keyword(s):  
Biological Activities ◽  
Reaction Times ◽  
Water Extract ◽  
Fish Bone ◽  
New Drugs ◽  
Bone Powder ◽  
Wide Range ◽  
Recoverable Catalysts ◽  
Egg Shell ◽  
Work Up

Background: 1,2,3-triazoles are an important class of organic compounds and because of their aromatic stability, they are not easily reduced, oxidized or hydrolyzed in acidic and basic environments. Moreover, 1,2,3-triazole derivatives are known by their important biological activities and have drawn considerable attention due to their variety of properties. The synthesis of this nucleus, based on the click chemistry concept, through the 1,3-dipolar addition reaction between azides and alkynes is a well-known procedure. This reaction has a wide range of applications, especially on the development of new drugs. Methods: The most prominent eco-friendly methods for the synthesis of triazoles under microwave irradiation published in articles from 2012-2018 were reviewed. Results: In this review, we cover some of the recent eco-friendly CuAAC procedures for the click synthesis of 1,2,3-triazoles with remarks to new and easily recoverable catalysts, such as rhizobial cyclic β-1,2 glucan; WEB (water extract of banana); biosourced cyclosophoraose (CyS); egg shell powder (ESP); cyclodextrin (β- CD); fish bone powder; nanoparticle-based catalyst, among others. Conclusion: These eco-friendly procedures are a useful tool for the synthesis of 1,2,3-triazoles, providing many advantages on the synthesis of this class, such as shorter reaction times, easier work-up and higher yields when compared to classical procedures. Moreover, these methodologies can be applied to the industrial synthesis of drugs and to other areas.

Metal and Non-Metal Catalysts in the Synthesis of Five-Membered S-Heterocycles

2019 ◽  
Vol 16 (2) ◽  
pp. 258-275 ◽  
Author(s):  
Navjeet Kaur
Keyword(s):  
Organic Synthesis ◽  
Biological Activities ◽  
Reaction Times ◽  
Research Field ◽  
Environmentally Benign ◽  
Metal Catalyst ◽  
Efficient Synthesis ◽  
Heterocyclic Molecules ◽  
The Past ◽  
Harsh Conditions

Background:A wide variety of biological activities are exhibited by N, O and S containing heterocycles and recently, many reports appeared for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal and non-metal catalyst has become a highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of S-heterocylces in the presence of metal and non-metal catalyst. The synthesis of five-membered S-heterocycles is described here.Objective:There is a need for the development of rapid, efficient and versatile strategy for the synthesis of heterocyclic rings. Metal, non-metal and organocatalysis involving methods have gained prominence because traditional conditions have disadvantages such as long reaction times, harsh conditions and limited substrate scope.Conclusion:The metal-, non-metal-, and organocatalyst assisted organic synthesis is a highly dynamic research field. For ßthe chemoselective and efficient synthesis of heterocyclic molecules, this protocol has emerged as a powerful route. Various methodologies in the past few years have been pointed out to pursue more sustainable, efficient and environmentally benign procedures and products. Among these processes, the development of new protocols (catalysis), which avoided the use of toxic reagents, are the focus of intense research.

scholarly journals Synthesis and Characterization of Functionalize HY Zeolite With Sulfunic Acid, A Micro-meso Structure as an Efficient Reusable Catalyst in Organic Transformations

2021 ◽  
Author(s):  
Mojgan Zendehdel ◽  
Fatemeh Tavakoli
Keyword(s):  
Reaction Times ◽  
Solvent Free ◽  
Reusable Catalyst ◽  
Organic Transformations ◽  
Hy Zeolite ◽  
New Class ◽  
Solvent Free Condition ◽  
Result Show ◽  
High Yields

Abstract A new class of catalyst has been prepared with sulfunic acid functionalized HY zeolite (HY-N-SO3H) and characterized by FESEM, TEM, FTIR, TGA, XRD and BET. The result show that the catalyst has the micro-meso structure without ordering in the mesophase. Then, two sets of organic reaction were examined to consider of catalytic activity. The micro-meso structure HY-N-SO3H was used as an acidic catalyst to synthesis of coumarins via Pechmann reaction and facile transformation of amines to formamides under solvent free condition. This catalyst was compared with NaY-N-SO3H and MCM-N-SO3H and pure porous material to consider of the effect of acidity and kind and size of porous in the catalyst. The significant advantages of HY-N-SO3H respect to other catalyst are short reaction times, high yields, pure products, mild conditions and easy workup. In addition, we report an original and environmentally friendly solvent-free procedures which reusability of catalyst makes this method nearly green and environmental friendly.

scholarly journals Synthesis of aminonaphthoquinone derivatives with Ceric Ammonium Nitrate (CAN) as a catalyst: NMR characterization and in silico reaction mechanism

2020 ◽  
Author(s):  
Jhoan H Piermattey ◽  
Jhon Zapata-Rivera ◽  
Juan Oviedo ◽  
Ricardo Gaitan ◽  
Harold Gomez
Keyword(s):  
Reaction Mechanism ◽  
Dft Calculations ◽  
Ammonium Nitrate ◽  
Biological Activities ◽  
Reaction Times ◽  
Reaction Rates ◽  
Ceric Ammonium Nitrate ◽  
Hydrazoic Acid ◽  
Chromatographic Techniques ◽  
Nmr Characterization

Three different aminonaphthoquinones of great interest in medicinal chemistry due to their diverse biological activities were more efficiently synthesized and characterized starting from naphthoquinones with hydrazoic acid in the presence of ceric ammonium nitrate (CAN). We have previously reported a highly time demand synthesis of 2-amino-1,4-naphthoquinone and 2-amino-3-methyl-1,4-naphthoquinone in the absence of the CAN catalyst. In the current study, we have also obtained 3-amino-5-hydroxy-1,4-naphthoquinone and reduced all reaction times in the presence of CAN as a catalyst. Reaction rates have been increased to circa three times their original times. All aminonaphthoquinones have been characterized by NMR, vibrational, and chromatographic techniques. Additionally, we have proposed a reaction mechanism for the amination of naphthoquinone derivatives in an acid medium, based on in-depth DFT calculations.

scholarly journals Dimeric cyclobutane formation under continuous flow conditions using organophotoredox catalysed [2+2]-cycloaddition

2021 ◽  
Author(s):  
Helena Grantham ◽  
Marc Kimber
Keyword(s):  
Natural Products ◽  
Continuous Flow ◽  
Reaction Times ◽  
Functional Materials ◽  
Synthetic Route ◽  
Flow Conditions ◽  
Reaction Conditions ◽  
New Class ◽  
Cyclobutane Dimers ◽  
Flow Study

Radical cation-initiated dimerization of electron rich alkenes is an expedient method for the synthesis of cyclobutanes. By merging organophotoredox catalysis and continuous flow technology a batch versus continuous flow study has been performed providing a convenient synthetic route to an important carbazole cyclobutane material dimer t-DCzCB using less only 0.1 mol% of an organophotoredox catalyst. The scope of this methodology was explored giving a new class of functional materials, as well as an improved synthetic route to styrene based lignan dimeric natural products. The cyclobutane dimers could be isolated in higher chemical yields under continuous flow conditions and reaction times were reduced significantly compared to traditional batch reaction conditions.

Activated Carbon/MoO3: Efficient Catalyst for Green Synthesis of Chromeno[d]pyrimidinediones and Xanthenones

2020 ◽  
Vol 23 ◽  
Author(s):  
Niloofar Sabet Mehr ◽  
Shahrzad Abdolmohammadi ◽  
Maryam Afsharpour
Keyword(s):  
Activated Carbon ◽  
Room Temperature ◽  
Bulk Material ◽  
Biological Activities ◽  
Reaction Times ◽  
Aromatic Aldehydes ◽  
Biologically Active ◽  
Efficient Catalyst ◽  
Calcium Blockers ◽  
High Yields

Background: Nanoscale metal oxide catalysts have been extensively employed in organic reactions because they have been found to influence the chemical and physical properties of the bulk material. The chromene (benzopyran) nucleus constitutes the core structure in a major class of many biologically active compounds, and interest in their chemistry consequently continues because of their numerous biological activities. The xanthene (dibenzopyran) derivatives are classified as highly significant compounds which display a number of various bioactive properties. Pyrimidinones have also gained interest due to their remarkable biological utilization such as antiviral, antibacterial, antihypertensive, antitumor and calcium blockers effects. Objective: Our aim in the work presented herein was to prepare activated carbon/MoO3 nanocomposite and explore its role as a green and recyclable catalyst for the synthesis of chromeno[d]pyrimidinediones and xanthenones under ethanol-drop grinding at room temperature. Methods: The activated carbon/MoO3 nanocomposite was prepared successfully via a simple route in which carbonization of gums as new natural precursors was used for the synthesis of activated carbon. This nanocomposite was then effectively used in a reaction of 3,4- methylenedioxyphenol, aromatic aldehydes and active methylene compounds including 1,3-dimethylbarbituric acid and dimedone to synthesize a series of chromeno[d]pyrimidinediones and xanthenones in high yields. The synthesized catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), Powder x-ray diffractometry (XRD), Scanning electron microscope (SEM), Raman spectroscopy, and also by TGA analysis. Confirmation of the structures of compounds 5(a-g) and 6(a-g) were also established with IR, 1 H NMR and 13C NMR spectroscopic data and also by elemental analyses. Results: A number of 6,8-dimethyl-10-phenyl-6,10-dihydro-7H-[1,3]dioxolo[4΄,5΄:6,7]chromeno[2,3-d]pyrimidine-7,9(8H)-diones and 7,7- dimethyl-10-(4-methylphenyl)-6,7,8,10-tetrahydro-9H-[1,3]dioxolo[4,5-b]xanthen-9-ones were effectively synthesized using activated carbon/MoO3 nanocomposite (0.05 gr) as catalyst under ethanol-drop grinding at room temperature. The desired products were obtained in high yields (93-97%) within short reaction times (15-20 min). Conclusion: This paper investigates the catalytic potential of the synthesized activated carbon/MoO3 nanocomposite for the prepataion of chromeno[d]pyrimidinediones and xanthenones under ethanol-drop grinding procedure. The mildness of the reaction conditions, high yields of products, short reaction times, experimental simplicity, and avoid the use of harmful solvents or reagents makes this procedure preferable for the synthesis of these compounds.

Advances in the Synthesis of Xanthenes: An Overview

2018 ◽  
Vol 15 (3) ◽  
pp. 341-369 ◽  
Author(s):  
Ankita Chaudhary ◽  
Jitender M. Khurana
Keyword(s):  
Heterogeneous Catalysts ◽  
Biological Activities ◽  
Reaction Times ◽  
Environmentally Benign ◽  
Central Nucleus ◽  
Diversity Oriented Synthesis ◽  
Wide Range ◽  
Privileged Scaffold ◽  
Synthetic Methodologies ◽  
Reaction Media

Background: Xanthene is pharmacologically important oxygen containing heterocyclic moeity exhibiting an array of potent biological activities like antibacterial, antiviral, antiinflammatory, antitumor, antioxidant, antiplasmodial etc. Other useful applications of these heterocycles are as fluorescent materials for the visualization of biomolecules and in laser technology. Objective: This review gives an insight of the literature available on the methods for the construction of xanthene nucleus. This review article can be reasonably encouraging for those involved in the synthesis of molecules exhibiting a wide range of biological activities involving xanthene as central nucleus and would provide them assistance in developing new eco-friendly, efficient and economical viable methods. Conclusion: Owing to diverse applications of xanthenes, various synthetic methodologies have been developed, whether to construct this privileged scaffold. Many of the reported methods involve the use of various harsh catalysts/reagents that are not environmentally benign, produce a large amount of waste and need longer reaction times. The sustainable and diversity oriented synthesis of xanthene scaffold which incorporates Green Chemistry tools like multicomponent reaction approach, heterogeneous catalysts, alternate reaction media such as water, ionic liquids, polyethylene glycol etc. has also been developed.

scholarly journals Synthesis and Antimicrobial Activities of N-(Heteroaryl-substituted)-p-toluenesulphonamides

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Ozoh Chinwe Francisca ◽  
Okoro Uchechukwu Chris ◽  
Ugwu David Izuchukwu
Keyword(s):  
Biological Activities ◽  
Condensation Reaction ◽  
Antimicrobial Activities ◽  
Diffusion Method ◽  
Gram Positive Bacteria ◽  
New Class ◽  
Bacteria And Fungi ◽  
Antibacterial And Antifungal ◽  
C Nmr

A new class of N-(heteroaryl-substituted)-p-toluenesulphonamides has been synthesized exhibiting antibacterial and antifungal properties. The condensation reaction of p-toluenesulphonyl chloride 1 with appropriate substituted amino pyridines 2a–g in acetone furnished N-(heteroaryl-substituted)-p-toluenesulphonamides 3a–g. These derivatives were characterized by IR, 1H-, and 13C-NMR spectroscopy and were screened in vitro against gram-positive bacteria, gram-negative bacteria, and fungi organisms using agar-diffusion method. Results indicated improved biological activities over reference drugs such as Tetracycline (TCN) and Fluconazole (FLU).

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