scholarly journals SYNTHESIS AND PROPERTIES OF CHALCONES BASED ON DEHYDROACETIC ACID

2021 ◽  
Vol 87 (5) ◽  
pp. 3-14
Author(s):  
Iryna Tretyakova ◽  
Viktor Chernii ◽  
Natalia Fedosova ◽  
Iryna Denisenko ◽  
Yan Dovbii ◽  
...  
Keyword(s):  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Visible Range ◽  
Knoevenagel Reaction ◽  
Oh Groups ◽  
Methyl Group ◽  
Organic Bases ◽  
Dehydroacetic Acid ◽  
Composition And Structure ◽  
Intramolecular Hydrogen

The Knoevenagel condensation reaction between dehydracetic acid and aromatic aldehydes is described in this work. The reaction is carried out directly between dehydroacetic acid and aromatic aldehydes in the presence of organic bases. The optimal conditions for the Knoevenagel reaction based on dehydroacetic acid and various aldehydes were determined. Twenty-one chalcones with substituents of different nature were synthesized. The composition and structure of the obtained compounds were determined. All characteristic signals of chalcones are present in the 1H NMR spectra of the obtained compounds registered in CDCl3 and DMSO-d6: OH groups in the range of 18.7–16.5 ppm, CH proton – 6.3–5.9 ppm, and methyl group of the pyran cycle 2.3–2.2 ppm. The corresponding signals of methine protons and aryl substituents are also present in the spectra. The most sensitive to solvent changes is the OH proton bound by an intramolecular hydrogen bond to the carbonyl group of the pyran ring. Signals in DMSO are usually shifted by 0.1–1.0 ppm in a stronger field compared to CDCl3 for dehydroacetic acid and chalcones based on it. CH proton signals are shifted by approximately 0.3 ppm in a weaker field, and the signals of the protons of the methyl group are almost insensitive to the solvent. The optical properties of obtained compounds were investigated in DMF, MeOH, MeCN. The synthesized chalcones absorb light in the visible range 330–490 nm with molar extinction coefficients of 3.5–4.5. The solvatochromic effects for most of them are weak – the position of the maximum changes by less than 10 nm. The electron-donor substituents in the phenyl ring (-NMe2 and -NEt2) shift the absorption ma­ximum bathochromically by almost 100 nm compared to others in all investigated solvents.

DFT Study and Synthesis of Novel Bioactive Bispyrazole Using Mg/AlLDH as a Solid Base Catalyst

2020 ◽  
Vol 14 ◽  
Author(s):  
Soufiane Akhramez ◽  
Youness Achour ◽  
Mustapha Diba ◽  
Lahoucine Bahsis ◽  
Hajiba Ouchetto ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Experimental Finding ◽  
Biological Activities ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Mechanistic Study ◽  
Knoevenagel Reaction ◽  
Solid Base ◽  
Reaction Conditions ◽  
Aryl Aldehyde

Background: In this study, an efficient synthesis of novel bispyrazole heterocyclic molecules by condensation of substituted aromatic aldehydes with 1,3-diketo-N-phenylpyrazole by using Mg/Al-LDH as heterogeneous catalyst is reported. The attractive features of this protocol are as follows: mild reaction conditions, good yields and easiness of the catalyst separation from the reaction mixture. Further, a mechanistic study has been performed by using DFT calculations to explain the observed selectivity of the condensation reaction between aryl aldehyde and 1,3-diketo-N-phenylpyrazole via Knoevenagel reaction. The local electrophilicity/ nucleophilicity that allows explaining correctly the experimental finding. Methods: The bispyrazole derivatives 3a-m were prepared by condensation reaction of substituted aromatic aldehydes with 1,3-diketo-Nphenylpyrazole by using Mg/Al-LDH as heterogeneous catalyst under THF solvent at the refluxing temperature. Objective: To synthesize a novel bispyrazole heterocyclic molecule may be have important biological activities and thus can be good candidates for pharmaceutical applications. Results: This protocol describes the Synthesis of Bioactive Compounds under mild reaction conditions, good yields and easiness of the catalyst separation from the reaction mixture. Further, a mechanistic study has been performed by using DFT calculations to explain the observed selectivity of the condensation reaction between aryl aldehyde and 1,3-diketo-N-phenylpyrazole via Knoevenagel reaction. The local electrophilicity/ nucleophilicity that allows explaining correctly the experimental finding. Conclusion: In summary, the pharmacologically interesting bis-pyrazole derivatives have been synthesized through Mg/Al-LDH as a solid base catalyst, in THF as solvent. Thus, the synthesized bioactive compounds containing the pyrazole ring may be have important biological activities and thus can be good candidates for pharmaceutical applications. Therefore, the catalyst Mg/Al-LDH showed high catalytic activity. Besides, a series of bispyrazole molecules were synthesized with a good yield and easy separation of the catalyst by simple filtration. Moreover, DFT calculations and reactivity indexes are used to explain the selectivity of the condensation reaction between aryl benzaldehyde and 1,3-diketo-Nphenylpyrazole via Knoevenagel reaction, and the results are in good agreement with the experimental finding.

Synthesis of 3-(Cyclohexylamino)-2-arylimidazo[1,2-a]pyridine-8- carboxylic Acids Via an Efficient Three-component Condensation Reaction between Cyclohexylisocyanide and 2-Aminopyridine-3-carboxylic Acid in the Presence of Aromatic Aldehyde

2018 ◽  
Vol 21 (4) ◽  
pp. 298-301 ◽  
Author(s):  
Ghasem Marandi
Keyword(s):  
Biological Sciences ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
High Performance ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
New Materials ◽  
One Pot ◽  
High Yields ◽  
Benzaldehyde Derivatives

Aim and Objective: The reaction of cyclohexylisocyanide and 2-aminopyridine-3- carboxylic acid in the presence of benzaldehyde derivatives in ethanol led to 3-(cyclohexylamino)-2- arylimidazo[1,2-a]pyridine-8-carboxylic acids in high yields. In a three component condensation reaction, isocyanide reacts with 2-aminopyridine-3-carboxylic acid and aromatic aldehydes without any prior activation. Material and Methods: The synthesized products have stable structures which have been characterized by IR, 1H, 13C and Mass spectroscopy as well as CHN-O analysis. Results: In continuation of our attempts to develop simple one-pot routes for the synthesis of 3- (cyclohexylamino)-2-arylimidazo[1,2-a]pyridine-8-carboxylic acids, aromatic aldehydes with divers substituted show a high performance. Conclusion: In conclusion, this study introduces the art of combinatorial chemistry using a simple one-pot procedure for the synthesis of new materials which are interesting compounds in medicinal and biological sciences.

scholarly journals Synthesis and biological activity of 4-thiazolidinone derivatives of phenothiazine

2012 ◽  
Vol 77 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Ritu Sharma ◽  
Pushkal Samadhiya ◽  
Savitri Srivastava ◽  
Santosh Srivastava
Keyword(s):  
Antimicrobial Activity ◽  
Heterocyclic Compounds ◽  
Thioglycolic Acid ◽  
Cycloaddition Reaction ◽  
Aromatic Aldehydes ◽  
Knoevenagel Reaction ◽  
Antituberculosis Activity ◽  
Bacteria And Fungi ◽  
Derivatives Of ◽  
Anhydrous Zncl2

A new series of N-[3-(10H-phenothiazinyl)-propyl]-2-(substituted phenyl)-4-oxo-5-( substituted benzylidene)-1,3-thiazolidine-carboxamide, 5(as) have been synthesized. The cycloaddition reaction of thioglycolic acid with N-[3-(10H-phenothiazinyl)-propyl]-N?-[(substituted phenyl)-methylidene]- urea, 3(a-s) in the presence of anhydrous ZnCl2 afforded new heterocyclic compounds N-[3-(10H-phenothiazinyl)-propyl]-2-(substituted phenyl)-4-oxo- 1,3-thiazolidine-carboxamide, 4(a-s). The later product on treatment with several selected substituted aromatic aldehydes in the presence of C2H5ONa undergoes Knoevenagel reaction to yield 5(a-s). The structure of compounds 1, 2, 3(a-s), 4(a-s) and 5(a-s) were confirmed by IR, 1H NMR, 13C NMR, Fmass and chemical analysis. All above compounds were screened for their antimicrobial activity against some selected bacteria and fungi and for antituberculosis activity compounds have been screened against the bacterium M. tuberculosis.

The photochemical reactivity of some benzoylthiophenes. IV. The effect of an adjacent methyl group on the excited state reactivity of 3-benzoylthiophene

1978 ◽  
Vol 56 (15) ◽  
pp. 1970-1984 ◽  
Author(s):  
D. R. Arnold ◽  
C. P. Hadjiantoniou
Keyword(s):  
Hydrogen Abstraction ◽  
Thiophene Ring ◽  
Emission Spectra ◽  
Photochemical Reactions ◽  
Triplet States ◽  
Photochemical Reactivity ◽  
Methyl Group ◽  
State Diagrams ◽  
Phosphorescence Emission ◽  
Intramolecular Hydrogen

The electronic absorption and phosphorescence emission spectra and the photochemical reactivity of several methyl-3-benzoylthiophenes (2- and 4-methyl-3-benzoylthiophene (1, 2), 2,5-dimethyl-3-benzoylthiophene (3), and 3-(2-methylbenzoyl)thiophene (4)) have been studied. Partial state diagrams have been constructed. The lowest energy absorption in hexane solution in every case is the carbonyl n → π* transition. The two lowest triplet states of these ketones are close in energy and, in fact, the nature of the emitting triplet (n,π* or π,π*) depends upon the position of methyl substitution and upon the solvent. The photochemical reactions studied include intramolecular hydrogen abstraction (revealed by deuterium exchange in the adjacent methyl group upon irradiation in perdeuteriomethanol solution), photocycloaddition of dimethyl acetylenedicarboxylate to the thiophene ring, and photocycloaddition of isobutylene to the carbonyl group. Generalizations, potentially useful for predicting photochemical reactivity of these and other aromatic ketones are summarized.

Green Synthesis and Biological Study of Pyrimidone derivatives employing Cetyltrimethyl ammonium bromide under solvent free condition

2021 ◽  
Vol 25 (11) ◽  
pp. 38-40
Author(s):  
S.R. Jagtap ◽  
R.P. Yadav ◽  
B.B. Bahule ◽  
D.J. Chaudhari
Keyword(s):  
Condensation Reaction ◽  
Biginelli Reaction ◽  
Aromatic Aldehydes ◽  
Solvent Free ◽  
Environmentally Benign ◽  
Biological Study ◽  
Ammonium Bromide ◽  
Solvent Free Condition ◽  
Cetyltrimethyl Ammonium ◽  
Anti Fungal

In this study, we are reporting a solvent free Biginelli reaction using aromatic aldehydes, ethyl acetoacetate and urea in presence of cetyl tri-methyl ammonium bromide as a catalyst. The reaction is green and environmentally benign. The yield of three component condensation reaction is excellent. The products were screened for anti-bacterial and anti-fungal activity. The method is simple and convenient. The catalyst is novel and easily available, non-expensive and nontoxic.

Methanogenesis from Acetate by Methanosarcina barkeri: Catalysis of Acetate Formation from Methyl Iodide, CO2 , and H2 by the Enzyme System Involved

1987 ◽  
Vol 42 (4) ◽  
pp. 360-372 ◽  
Author(s):  
Kerstin Laufer ◽  
Bernhard Eikmanns ◽  
Ursula Frimmer ◽  
Rudolf K. Thauer
Keyword(s):  
Methyl Iodide ◽  
Condensation Reaction ◽  
Methyl Chloride ◽  
Methanosarcina Barkeri ◽  
Carboxyl Group ◽  
Atpase Inhibitor ◽  
Methyl Group ◽  
Proton Potential ◽  
Acetate Formation ◽  
Reducing Equivalents

Cell suspensions of Methanosarcina barkeri grown on acetate catalyze the formation of methane and CO2 from acetate as well as an isotopic exchange between the carboxyl group of acetate and CO2. Here we report that these cells also mediate the synthesis of acetate from methyl iodide, CO2, and reducing equivalents (H2 or CO), the methyl group of acetate being derived from methyl iodide and the carboxyl group from CO2. Methyl chloride and methyltosylate but not methanol can substitute for methyl iodide in this reaction. Acetate formation from methyl iodide, CO2, and reducing equivalents is coupled with the phosphorylation of ADP. Evidence is pres­ented that methyl iodide is incorporated into the methyl group of acetate via a methyl corrinoid intermediate (deduced from inhibition experiments with propyl iodide) and that CO2 is assimi­lated into the carboxyl group via a C1 intermediate which does not exchange with free formate or free CO. The effects of protonophores, of the proton-translocating ATPase inhibitor N.N′-di- cyclohexylcarbodiimide, and of arsenate on acetate formation are interpreted to indicate that the reduction of CO2 to the oxidation level of the carboxyl group of acetate requires the presence of an electrochemical proton potential and that acetyl-CoA or acetyl-phosphate rather than free acetate is the immediate product of the condensation reaction. These results are discussed with respect to the mechanism of methanogenesis from acetate.

scholarly journals Benzazole derivatives, IV: Reaction of 1,2,3-trimethylbenzimidazolium salts with aromatic aldehydes

2005 ◽  
Vol 70 (12) ◽  
pp. 1381-1388 ◽  
Author(s):  
Cernatescu Corina ◽  
Comanita Eugenia
Keyword(s):  
Ir Spectroscopy ◽  
Benzene Ring ◽  
Absorption Spectroscopy ◽  
Electronic Absorption ◽  
Aromatic Aldehydes ◽  
Electronic Absorption Spectroscopy ◽  
Methyl Group ◽  
Practical Applications ◽  
Hemicyanine Dyes

1,2,3-Trimethylbenzimidazolium iodide and its analogue salts with one or two substituents on benzene ring (X=NO2,Br,Cl,CH3) are, due to the reactivity of the 2-methyl group, able to react with para-substituted aromatic aldehydes (X=OH,OCH3,CH3,NMe2,NO2) using piperidine as a catalyst. 1-Methyl-2-styrylbenzimidazole iodomethylates were obtained and their structure elucidated by means of NMR and IR spectroscopy. The compounds are interesting as hemicyanine dyes. They lend themselves to studies based on electronic absorption spectroscopy and they have potential practical applications linked to their photosensitive properties.

Ball Mill–assisted Preparation of Nano-CaCO3 as a Novel and Green Catalyst–based Eggshell Waste

2013 ◽  
Vol 1 ◽  
pp. 194308921350716 ◽  
Author(s):  
Elaheh Mosaddegh ◽  
Asadollah Hassankhani ◽  
Sadegh Pourahmadi ◽  
Dadkhoda Ghazanfari
Keyword(s):  
Ball Mill ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
High Catalytic Activity ◽  
X Ray Diffraction ◽  
Green Catalyst ◽  
Solvent Free Conditions ◽  
High Efficient ◽  
Particle Sizer ◽  
Eggshell Waste

Ball mill–assisted preparation of nano-bio Calcite (CaCO3) based on avian shell and its application as a novel, biodegradable, and heterogeneous catalyst with high catalytic activity and reusability in the green and high efficient synthesis of pyrano[4,3- b]pyrans via a condensation reaction of different aromatic aldehydes, malononitrile, and 4-hydroxy-6-methyl-2 H-pyran-2-one at 120°C under solvent-free conditions is reported. The reaction proceeds to completion within 5–30 min in 90–98% yield. The nanocatalyst was characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscope (SEM), elemental analysis, and laser particle sizer.

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