FUNDAMENTAL AND APPLIED ASPECTS OF THE CHEMISTRY OF ACETYLENYLQUINONES

In addition to the reported synthetic routes for the acetylene derivatives of quinones, a detailed analysis of the fundamental chemical, physicochemical, and biological properties of this class of compounds is presented herein. The advantages of Pd- and Cu-catalyzed cross-coupling of terminal alkynes with iodarenes via the Sonogashira reaction to produce new acetylenylquinones with predetermined properties are examined. Here, combining quinoid and acetylene residues into one molecule gives the resulting compounds chemical specificity, as demonstrated by several reported examples of non-trivial transformations. In particular, the presence of the quinoid cycle significantly increases the electrophilicity of the triple bond and determines the range of transformation possibilities. Moreover, acetylenylquinones have heightened sensitivity to both external (such as the reaction temperature and the nature of the solvent) and internal (e.g., the structure of substituents in the nucleus and the acetylene fragment) factors. For example, regioselective cleavage of a strong triple bond under the action of amines is possible in the absence of a metal catalyst. Peri-substituted acetylenyl-9,10-anthraquinones are most suited for the synthetic route because of the proximity of the acetylene and carbonyl groups. Mechanisms of reactions of selective alkynylquinones are described.

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Synthesis and therapeutic potential of imidazole containing compounds

BMC Chemistry ◽

10.1186/s13065-020-00730-1 ◽

2021 ◽

Vol 15 (1) ◽

Author(s):

Ankit Siwach ◽

Prabhakar Kumar Verma

Keyword(s):

Therapeutic Potential ◽

Biological Activities ◽

Biological Properties ◽

New Drugs ◽

Hydrogen Atoms ◽

Tautomeric Forms ◽

Synthetic Routes ◽

Derivatives Of ◽

Heterocyclic Moiety ◽

Antihistaminic Agent

Abstract Imidazole is a five-membered heterocyclic moiety that possesses three carbon, two nitrogen, four hydrogen atoms, and two double bonds. It is also known as 1, 3-diazole. It contains two nitrogen atoms, in which one nitrogen bear a hydrogen atom, and the other is called pyrrole type nitrogen. The imidazole name was reported by Arthur Rudolf Hantzsch (1857–1935) in 1887. 1, 3-diazole is an amphoteric in nature i.e. it shows both acidic and basic properties. It is a white or colorless solid that is highly soluble in water and other polar solvents. Due to the presence of a positive charge on either of two nitrogen atom, it shows two equivalent tautomeric forms. Imidazole was first named glyoxaline because the first synthesis has been made by glyoxal and ammonia. It is the basic core of some natural products such as histidine, purine, histamine and DNA based structures, etc. Among the different heterocyclic compounds, imidazole is better known due to its broad range of chemical and biological properties. Imidazole has become an important synthon in the development of new drugs. The derivatives of 1, 3-diazole show different biological activities such as antibacterial, antimycobacterial, anti-inflammatory, antitumor, antidiabetic, anti-allergic, antipyretic, antiviral, antioxidant, anti-amoebic, antihelmintic, antifungal and ulcerogenic activities, etc. as reported in the literature. There are different examples of commercially available drugs in the market which contains 1, 3-diazole ring such as clemizole (antihistaminic agent), etonitazene (analgesic), enviroxime (antiviral), astemizole (antihistaminic agent), omeprazole, pantoprazole (antiulcer), thiabendazole (antihelmintic), nocodazole (antinematodal), metronidazole, nitroso-imidazole (bactericidal), megazol (trypanocidal), azathioprine (anti rheumatoid arthritis), dacarbazine (Hodgkin's disease), tinidazole, ornidazole (antiprotozoal and antibacterial), etc. This present review summarized some pharmacological activities and various kinds of synthetic routes for imidazole and their derived products.

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Therapeutic potential of oxadiazole or furadiazole containing compounds

BMC Chemistry ◽

10.1186/s13065-020-00721-2 ◽

2020 ◽

Vol 14 (1) ◽

Author(s):

Ankit Siwach ◽

Prabhakar Kumar Verma

Keyword(s):

Therapeutic Potential ◽

Biological Activities ◽

Antiviral Drug ◽

Biological Properties ◽

New Drugs ◽

Pharmacological Activities ◽

Methylene Groups ◽

Synthetic Routes ◽

Azole Ring ◽

Derivatives Of

AbstractAs we know that, Oxadiazole or furadi azole ring containing derivatives are an important class of heterocyclic compounds. A heterocyclic five-membered ring that possesses two carbons, one oxygen atom, two nitrogen atoms, and two double bonds is known as oxadiazole. They are derived from furan by the replacement of two methylene groups (= CH) with two nitrogen (-N =) atoms. The aromaticity was reduced with the replacement of these groups in the furan ring to such an extent that it shows conjugated diene character. Four different known isomers of oxadiazole were existed such as 1,2,4-oxadiazole, 1,2,3-oxadiazole, 1,2,5-oxadiazole & 1,3,4-oxadiazole. Among them, 1,3,4-oxadiazoles & 1,2,4-oxadiazoles are better known and more widely studied by the researchers due to their broad range of chemical and biological properties. 1,3,4-oxadiazoles have become important synthons in the development of new drugs. The derivatives of the oxadiazole nucleus (1,3,4-oxadiazoles) show various biological activities such as antibacterial, anti-mycobacterial, antitumor, anti-viral and antioxidant activity, etc. as reported in the literature. There are different examples of commercially available drugs which consist of 1,3,4-oxadiazole ring such as nitrofuran derivative (Furamizole) which has strong antibacterial activity, Raltegravir as an antiviral drug and Nesapidil drug is used in anti-arrhythmic therapy. This present review summarized some pharmacological activities and various kinds of synthetic routes for 2, 5-disubstituted 1,3,4-oxadiazole, and their derived products.

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On differences in substituent effects in substituted ethene and acetylene derivatives and their boranyl analogs

Structural Chemistry ◽

10.1007/s11224-020-01666-x ◽

2020 ◽

Vol 32 (1) ◽

pp. 285-296

Author(s):

Mirosław Jabłoński ◽

Tadeusz M. Krygowski

Keyword(s):

Bond Length ◽

Triple Bond ◽

Wide Spectrum ◽

Substituent Effects ◽

Triple Bonds ◽

External Perturbations ◽

Substituent Constants ◽

The Impact ◽

Derivatives Of ◽

Acetylene Derivatives

AbstractThis article is the first attempt to present different influence of substituent effects on double and triple bonds and, conversely, to present the impact of these bonds on the electronic structure of substituents. For this purpose, quantum-mechanical calculations were made for X-substituted derivatives of ethene and acetylene with 27 diverse substituents representing a wide spectrum of electronic properties, from strongly electron-accepting to strongly electron-donating ones. In addition to these systems, their boranyl derivatives are also investigated. It turns out that the Hammett substituent constants do not correctly describe changes in the CC bond length in any of the considered family of systems. However, the relationships with the CB bond length are significantly better. It is shown that the triple bond in acetylene derivatives is much more resistant to external perturbations than the double bond in the analogs containing an ethene unit. As a consequence, in acetylene derivatives, the substituent effects on CC bond length are about half of the substituent effects in ethene derivatives. We suggest that the observed lack of a clear linear correlation between the length of the CC triple bond in acetylene derivatives and the value of electron density on this bond is due to the disturbing additional interaction between the structure of the X substituent in the xy plane and the π bond being in the same plane in the acetylene unit—on the contrary, this interaction is not possible in ethene analogs.

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Potentials of Diphenyl Ether Scaffold as a Therapeutic Agent: A Review

Mini-Reviews in Medicinal Chemistry ◽

10.2174/1389557519666190312150132 ◽

2019 ◽

Vol 19 (17) ◽

pp. 1392-1406

Author(s):

Suvarna G. Kini ◽

Ekta Rathi ◽

Avinash Kumar ◽

Varadaraj Bhat

Keyword(s):

Therapeutic Agent ◽

Diphenyl Ether ◽

Biological Properties ◽

Industrial Applications ◽

Synthetic Route ◽

Structure Activity ◽

Diphenyl Ethers ◽

Antiviral Activities ◽

Synthetic Routes ◽

The 19Th Century

Diphenyl ethers (DPE) and its analogs have exhibited excellent potential for therapeutic and industrial applications. Since the 19th century, intensive research is perpetuating on the synthetic routes and biological properties of DPEs. Few well-known DPEs are Nimesulide, Fenclofenac, Triclosan, Sorafenib, MK-4965, and MK-1439 which have shown the potential of this moiety as a lead scaffold for different pharmacological properties. In this review, we recapitulate the diverse synthetic route of DPE moiety inclusive of merits and demerits over the classical synthetic route and how this moiety sparked an interest in researchers to discern the SAR (Structure Activity Relationship) for the development of diversified biological properties of DPEs such as antimicrobial, antifungal, antiinflammatory & antiviral activities.

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Synthesis of Novel 1,2,3-Triazole Derivatives of Isocoumarins and 3,4-Dihydroisocoumarin with Potential Antiplasmodial Activity In Vitro

Medicinal Chemistry ◽

10.2174/1573406416666200602161047 ◽

2020 ◽

Vol 16 ◽

Author(s):

Lucas da Silva Santos ◽

Matheus Fillipe Langanke de Carvalho ◽

Ana Claudia de Souza Pinto ◽

Amanda Luisa da Fonseca ◽

Julio César Dias Lopes ◽

...

Keyword(s):

Triazole Ring ◽

Antiplasmodial Activity ◽

World Health ◽

Dipolar Cycloaddition ◽

Terminal Alkynes ◽

The World ◽

Ic50 Values ◽

Derivatives Of ◽

Active Substances

Background: Malaria greatly affects the world health, having caused more than 228 million cases only in 2018. The emergence of drug resistance is one of the main problems in its treatment, demonstrating the urge for the development of new antimalarial drugs. Objective: Synthesis and in vitro antiplasmodial evaluation of triazole compounds derived from isocoumarins and a 3,4- dihydroisocoumarin. Method: The compounds were synthesized in 4 to 6-step reactions with the formation of the triazole ring via the Copper(I)-catalyzed 1,3-dipolar cycloaddition between isocoumarin or 3,4-dihydroisocoumarin azides and terminal alkynes. This key reaction provided compounds with an unprecedented connection of isocoumarin or 3,4-dihydroisocoumarin and the 1,2,3-triazole ring. The products were tested for their antiplasmodial activity against a Plasmodium falciparum chloroquine resistant and sensitive strains (W2 and 3D7, respectively). Results: Thirty-one substances were efficiently obtained by the proposed routes with an overall yield of 25-53%. The active substances in the antiplasmodial test displayed IC50 values ranging from 0.68-2.89 μM and 0.85-2.07 μM against W2 and 3D7 strains, respectively.

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Binding of calcium and lead ions to carboxystarch prepared by action of nitrogen dioxide on native starch and its 2,3-dialdehyde derivatives

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19861340 ◽

1986 ◽

Vol 51 (6) ◽

pp. 1340-1351 ◽

Cited By ~ 3

Author(s):

Rudolf Kohn ◽

Karol Tihlárik

Keyword(s):

Nitrogen Dioxide ◽

Alkaline Medium ◽

Binding Capacity ◽

Lead Ions ◽

Carbonyl Groups ◽

Weakly Alkaline ◽

Exchange Cations ◽

Counter Ions ◽

The Stability ◽

Derivatives Of

The binding of calcium and lead ions to carboxy derivatives of starch prepared by allowing nitrogen dioxide to act on native maize starch (procedure A) and on starch 2,3-dialdehyde derivatives of degrees of oxidation DO(d.a.) ≥ 0.94 (procedure B) was studied. The carboxy group content of the samples in the H+ form was 4.6 - 12.1 mmol g-1. The effect of alkaline medium on the stability of the carboxy derivatives and on their ability to bind and exchange cations was examined. The Ca2+ → 2K+ exchange was evaluated in terms of the decrease in the electrostatic free enthalpy Δ(Gel/N)KCa, determined by alkalimetric potentiometric titrations, and the binding of Pb2+ ions was evaluated in terms of the activity of the Pb2+ counter-ions determined in suspensions of Pb salts of the carboxy derivatives by means of an ion specific electrode. The IR and CD spectra revealed that the carboxystarch preparations obtained by procedure A contained, in addition to free carboxy groups, a considerable amount of carbonyl groups. During the conversion of the latter groups to the former, even in a weakly alkaline medium, the carboxy derivatives undergo an appreciable degradation and lose, to a great extent, their ability to bind and exchange cations. Procedure B, on the other hand, leads to highly selective starch and amylose carboxy derivatives, exhibiting a small amount of carbonyl groups and featuring a relative stability towards alkaline medium; their binding capacity is as high as 12 milliequivalents of cations per g of sample.

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1,3-dipolar cycloaddition in the synthesis of glycoconjugates of natural chlorins and bacteriochlorins

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424609000425 ◽

2009 ◽

Vol 13 (03) ◽

pp. 336-345 ◽

Cited By ~ 16

Author(s):

Mikhail A. Grin ◽

Ivan S. Lonin ◽

Anna A. Lakhina ◽

Elena S. Ol'shanskaya ◽

Alexey I. Makarov ◽

...

Keyword(s):

Triple Bond ◽

Tautomeric Form ◽

Click Reaction ◽

Copper Cation ◽

Water Soluble ◽

Dipolar Cycloaddition ◽

Nmr Studies ◽

Metal Free ◽

Cu Complex ◽

Derivatives Of

Glucose-, galactose- and lactose-containing photosensitizers based on derivatives of chlorophyll a and bacteriochlorophyll a were synthesized with the use of [3+2] cycloaddition between sugar azides and triple bond derivatives of chlorins and bacteriochlorins. Unlike bacteriochlorin cycloimide, chlorin was detected to form a Cu -complex during the click reaction. An approach to the synthesis of metal-free glycosylated chlorins was developed with the use of "protection" by Zn 2+ cation and subsequent demetalation. It is based on the action of alkynyl chlorin e6 derivative Zn -complex, which is resistant to the substitution by copper cation. Bacteriochlorin p cycloimide conjugate with per-acetylated β-D-lactose was obtained and shown to become water-soluble after unblocking of the lactose hydroxy functions. NMR studies allowed for the elucidation of structure, tautomeric form and conformation of the obtained compounds.

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