scholarly journals Synthesis of isoxazole and isothiazole derivatives of curcumin

2020 ◽  
Vol 56 (2) ◽  
pp. 187-191
Author(s):  
E. A. Akishina ◽  
E. A. Dikusar ◽  
S. K. Petkevich ◽  
V. I. Potkin
Keyword(s):  
Carboxylic Acid ◽  
Nmr Spectra ◽  
Antitumor Effect ◽  
Curcuma Longa ◽  
Antioxidant Properties ◽  
Antitumor Drugs ◽  
Carboxylic Acid Chloride ◽  
Curcumin Derivatives ◽  
Starting Compound ◽  
Derivatives Of

Curcumin is a chemical compound with antioxidant properties as well as strong anti-inflammatory, antiviral, analgesic, antimicrobial and antitumor effect, contained in the tuberous rhizomes of the turmeric plant (Curcuma longa). Curcumin derivatives are being intensively studied as potential drugs – antitumor drugs for the treatment of certain forms of cancer. The presence of reactive functional groups makes curcumin a convenient starting compound for the further chemical modification. The esters of curcumin and 5-phenylisoxazole-3-carboxylic acid, 5-(p-tolyl)isoxazole-3-carboxylic acid, 4,5- dichloroisothiazole-3-carboxylic acid and adduct of 5-(p-tolyl)isoxazol-3-carbaldehyde with curcumin were synthesized. Esters were obtained by acylation of curcumin with heterocycle-containing carboxylic acid chloride in diethyl ether in the presence of triethylamine. The IR and NMR spectra of the obtained compounds are described.

scholarly journals Selektive Metallierung von BicycIo[3.2.1]octa-2,6-dien, II Distannylierte Derivate und stannylierte tricyclische Sekundärprodukte / Selective Metalation of Bicyclo[3.2.1]octa-2,6-diene, II Distannylated Derivatives and Stannylated Tricyclic Secondary Products

1988 ◽  
Vol 43 (11) ◽  
pp. 1405-1415 ◽  
Author(s):  
N. Hertkorn ◽  
F. H. Köhler
Keyword(s):  
Nmr Spectroscopy ◽  
Low Temperature ◽  
Nmr Spectra ◽  
Considerable Change ◽  
Coupling Constants ◽  
Secondary Products ◽  
Starting Compound ◽  
Derivatives Of ◽  
C Nmr ◽  
Dibromo Derivative

Abstract Distannylated bicyclo[3.2.1]octa-2,6-diene (1) with (CH3)3 Sn groups in positions exo-4 and 7 (7a), endo-4 and 7 (7b), exo-4 and 6 (7c), and probably exo-4 and endo-4 (7d) are obtained when 1 is treated first with an excess of n-BuLi/t-BuOK in alkane and then with (CH3)3 SnCl. Byproducts are monostannylated derivatives of 1 and l,4-bis(trimethylstannyl)but-2-ene (3). The formation of 7a/b/c is best understood when the two possible bicyclo[3.2.1]octa-2,6-dienyl dianions are generated as intermediates. 3,exo-4-Bis(trimethylstannyl)bicyclo[3.2.1]octa-2,6-diene (7e) is ob-tained from the corresponding dibromo derivative of 1 and (CH3)3SnLi with 3-bromo-exo-4-trimethylstannylbicyclo[3.2.1]octa-2,6-diene (9) as an intermediate. The bicyclic stannyl com-pounds are susceptible to a 1,5-homopentadienyl shift of a (CH3)3Sn group at relatively low temperature when the starting compound has the stannyl group in position 4 of 1 and when positions 6 or 7 are unsubstituted. Tricyclo[3.2.1.02.7]oct-3-enes with (CH3)3Sn groups in positions exo-6 (5a), endo-6 (5b), 3 and exo-6 (10a), and 3 and endo-6 (10b) are thus obtained. On further heating, 10b gives l-trimethylstannyl-3-vinylbenzene (11). All compounds have been studied systematically by NMR spectroscopy including δ(119Sn), δ(13C), δ(1H), 4/5J(119/117Sn-119Sn), nJ(119/117Sn-13C) , nJ(119/117Sn-1H), 1J(13C-1H ) , and nJ(1H-1H ). Among all nuclei, 119Sn gives the most simple spectra. From the 13C NMR spectra a series of useful increments of (CH3)3Sn groups emerges. The most interesting coupling constants are 5J(119/117Sn-119Sn), for which a considerable change with the dihedral angle is established, and nJ(119/117Sn-13C). For n = 3 and 4 the latter are especially useful because their angular dependence leads to unambiguous signal assignments.

Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

2020 ◽  
Vol 16 (4) ◽  
pp. 481-488
Author(s):  
Heli Sanghvi ◽  
Satyendra Mishra
Keyword(s):  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Pyrazole Derivatives ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Curcumin Derivatives ◽  
Structure Activity ◽  
Electron Donating Groups ◽  
Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

Curcumin-based antioxidant and glycohydrolase inhibitor compounds: Synthesis and in vitro appraisal of the dual activity against diabetes

2020 ◽  
Vol 16 ◽  
Author(s):  
Sajjad Esmaeili ◽  
Nazanin Ghobadi ◽  
Donya Nazari ◽  
Alireza Pourhossein ◽  
Hassan Rasouli ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Enzyme Inhibitor ◽  
Radical Scavenging Activity ◽  
Curcuma Longa ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Inhibitory Effect ◽  
Curcumin Derivatives ◽  
Reducing Power Assay

Background: Curcumin, as the substantial constituent of the turmeric plant (Curcuma longa), plays a significant role in the prevention of various diseases, including diabetes. It possesses ideal structure features as enzyme inhibitor, including a flexible backbone, hydrophobic nature, and several available hydrogen bond (H-bond) donors and acceptors. Objective: The present study aimed at synthesizing several novel curcumin derivatives and further evaluation of these compounds for possible antioxidant and anti-diabetic properties along with inhibitory effect against two carbohydrate-hydrolyzing enzymes, α-amylase and α-glucosidase, as these enzymes are therapeutic targets for attenuation of postprandial hyperglycemia. Methods: Therefore, curcumin-based pyrido[2,3-d]pyrimidine derivatives were synthesized and identified using an instrumental technique like NMR spectroscopy and then screened for antioxidant and enzyme inhibitory potential. Total antioxidant activity, reducing power assay and 1,1-diphenyl-2-picrylhydrazyl (DPPH• ) radical scavenging activity were done to appraisal the antioxidant potential of these compounds in vitro. Results: Compounds L6-L9 showed higher antioxidant activity while L4, L9, L12 and especially L8 exhibited the best selectivity index (lowest α-amylase/α-glucosidase inhibition ratio). Conclusion: These antioxidant inhibitors may be potential anti-diabetic drugs, not only to reduce glycemic index but also to limit the activity of the major reactive oxygen species (ROS) producing pathways.

Preparation, properties and structure of some intermediate nido- and arachno-monocarbaboranes

1981 ◽  
Vol 46 (10) ◽  
pp. 2345-2353 ◽  
Author(s):  
Karel Baše ◽  
Bohumil Štíbr ◽  
Jiří Dolanský ◽  
Josef Duben
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Nmr Spectra ◽  
Liquid Ammonia ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Starting Compound

The 6-N(CH3)3-6-CB9H11 carbaborane reacts with sodium in liquid ammonia with the formation of 6-CB9H12- which was used as a starting compound for preparing the 4-CB8H14, 9-L-6-CB9H13 (L = (CH3)2S, CH3CN and P(C6H5)3), 1-(η5-C5H5)-1,2-FeCB9H10-, and 2,3-(η5-C5H5)2-2,31-Co2CB9H10- carboranes. The 4-CB8H14 compound was dehydrogenated at 623 K to give 4-(7)-CB8H12 carborane. Base degradation of 6-N(CH3)3-6-CB9H11 in methanol resulted in the formation of 3,4-μ-N(CH3)3CH-B5H10. The structure of all compounds was proposed on the basis of their 11B and 1H NMR spectra and X-ray diffraction was used in the case of the transition metal complexes.

Synthesis of Linear Steroid Oligoesters Based on Etienic Acid

2002 ◽  
Vol 67 (11) ◽  
pp. 1709-1718 ◽  
Author(s):  
Miroslav Reschel ◽  
Miloš Buděšínský ◽  
Ivan Černý ◽  
Vladimír Pouzar ◽  
Pavel Drašar
Keyword(s):  
Carboxylic Acid ◽  
Nmr Spectra ◽  
Mixed Anhydride

Linear oligoesters based on etienic acid (3β-hydroxyandrost-5-ene-17β-carboxylic acid) containing 2-4 steroid units were prepared employing mixed anhydride esterification. NMR spectra of the oligomeric steroids have been fully assigned.

scholarly journals Avocado-Derived Biomass: Chemical Composition and Antioxidant Potential

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 100
Author(s):  
Minerva C. García-Vargas ◽  
María del Mar Contreras ◽  
Irene Gómez-Cruz ◽  
Juan Miguel Romero-García ◽  
Eulogio Castro
Keyword(s):  
Chemical Composition ◽  
Phenolic Content ◽  
Antioxidant Properties ◽  
Total Phenolic ◽  
Nutritional Properties ◽  
Aqueous Fraction ◽  
Extraction Solvent ◽  
Main Components ◽  
A Minor ◽  
Derivatives Of

Avocado has become fashionable due to its great organoleptic and nutritional properties. It is consumed as a fresh product and it is also processed to obtain salad oil and guacamole. In all cases, the only usable portion is the pulp. Therefore, to be a more sustainable and profitable agribusiness, it is important to recognize which compounds from the peel and the stone waste can be converted into valuable bio-products. Therefore, their chemical composition was determined according to the National Renewable Energy Laboratory, the total phenolic content by the Folin-Ciocalteu method and the antioxidant properties by the FRAP and TEAC assays. The main components of the peel and stone were acid-insoluble lignin (35.0% and 15.3%, respectively), polymeric sugars (23.6% and 43.9%, respectively), and the aqueous extractives (15.5% and 16.9%, respectively). Both biomasses contain lipids and protein, but a minor proportion (<6%). The valorization of lignin and sugars is of interest given the high content; stones are a rich source of glucose (93.2% of the polymeric fraction), which could be used to obtain biofuels or derivatives of interest. The extractive fraction of the peel contained the highest number of phenolic compounds (4.7 g/100 g biomass), mainly concentrated in the aqueous fraction (i.e., 87%) compared to the ethanol one, which was subsequently extracted. It correlated with major antioxidant activity and, therefore, the peel can be applied to obtain antioxidants and water can be used as an environmentally friendly extraction solvent.

scholarly journals Novel Derivatives of 4-Methyl-1,2,3-Thiadiazole-5-Carboxylic Acid Hydrazide: Synthesis, Lipophilicity, and In Vitro Antimicrobial Activity Screening

2021 ◽  
Vol 11 (3) ◽  
pp. 1180
Author(s):  
Kinga Paruch ◽  
Łukasz Popiołek ◽  
Anna Biernasiuk ◽  
Anna Berecka-Rycerz ◽  
Anna Malm ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Carboxylic Acid ◽  
Bacterial Infections ◽  
Acid Hydrazide ◽  
Antimicrobial Effect ◽  
In Vitro Antimicrobial Activity ◽  
Research Goal ◽  
New Compounds ◽  
Derivatives Of

Bacterial infections, especially those caused by strains resistant to commonly used antibiotics and chemotherapeutics, are still a current threat to public health. Therefore, the search for new molecules with potential antimicrobial activity is an important research goal. In this article, we present the synthesis and evaluation of the in vitro antimicrobial activity of a series of 15 new derivatives of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid. The potential antimicrobial effect of the new compounds was observed mainly against Gram-positive bacteria. Compound 15, with the 5-nitro-2-furoyl moiety, showed the highest bioactivity: minimum inhibitory concentration (MIC) = 1.95–15.62 µg/mL and minimum bactericidal concentration (MBC)/MIC = 1–4 µg/mL.

Preparation of 2,3-Dideoxy-2,3-epimino and 3,4-Dideoxy-3,4-epimino Derivatives of 1,6-Anhydro-β-D-hexopyranoses by Mitsunobu Reaction

1998 ◽  
Vol 63 (6) ◽  
pp. 813-825 ◽  
Author(s):  
Jiří Kroutil ◽  
Tomáš Trnka ◽  
Miloš Buděšínský ◽  
Miloslav Černý
Keyword(s):  
Nmr Spectra ◽  
Mitsunobu Reaction ◽  
Derivatives Of ◽  
C Nmr

A series of new 2-, 3- and 4-benzylamino-2-, 3- and 4-deoxy derivatives of 1,6-anhydro-β-D-hexopyranoses were prepared from 1,6:2,3- and 1,6:3,4-dianhydro-β-D-hexopyranoses by treatment with benzylamine and converted into 2,3-(N-benzylepimino)-2,3-dideoxy- and 3,4-(N-benzylepimino)-3,4-dideoxy-β-D-hexopyranoses of the D-allo, D-galacto and D-talo configuration by Mitsunobu reaction. The structures of benzylamino and benzylimino derivatives were confirmed by 1H and 13C NMR spectra.

scholarly journals Synthesis and Characterization of the Germathioacid Chloride Coordinated by an N-Heterocyclic Carbene §

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 76 ◽  
Author(s):  
Yasunobu Egawa ◽  
Chihiro Fukumoto ◽  
Koichiro Mikami ◽  
Nobuhiro Takeda ◽  
Masafumi Unno
Keyword(s):  
Carboxylic Acid ◽  
Density Functional ◽  
Dft Calculation ◽  
Acid Chlorides ◽  
Carboxylic Acid Chloride ◽  
Functional Theory ◽  
Nitrogen Ligands ◽  
Bond Property ◽  
Nitrogen Bonds

Carboxylic acid chlorides are useful substrates in organic chemistry. Many germanium analogues of carboxylic acid chloride have been synthesized so far. Nevertheless, all of the reported germathioacid chlorides use bidentate nitrogen ligands and contain germanium-nitrogen bonds. Our group synthesized germathioacid chloride, Ge(S)Cl{C6H3-2,6-Tip2}(Im-i-Pr2Me2), using N-heterocyclic carbene (Im-i-Pr2Me2). As a result of density functional theory (DFT) calculation, it was found that electrons are localized on sulfur, and the germanium-sulfur bond is a single bond with a slight double bond property.

Some Basic Derivatives of 3-Methylflavone-8-carboxylic Acid

1960 ◽  
Vol 2 (3) ◽  
pp. 263-269 ◽  
Author(s):  
Paolo Da Re ◽  
Lucia Verlicchi ◽  
Ivo Setnikar
Keyword(s):  
Carboxylic Acid ◽  
Derivatives Of
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