scholarly journals Convenient approaches to the synthesis of 6-amino- and 6-oxoimidazo[4,5-b]pyrazolo[3,4-e]pyridines

2021 ◽  
Vol 19 (1(73)) ◽  
pp. 10-15
Author(s):  
G. G. Yakovenko ◽  
M. V. Vovk
Keyword(s):  
Acetic Acid ◽  
Carboxylic Acid ◽  
Ir Spectra ◽  
Carboxylic Acids ◽  
1H Nmr ◽  
Nmr Spectra ◽  
1H Nmr Spectra ◽  
Biologically Active ◽  
Spectral Measurements ◽  
Absorption Bands

Aim. To develop convenient approaches to the synthesis of 6-amino- and 6-oxoimidazo[4,5-b]pyrazolo[3,4-e]pyridines as promising biologically active scaffolds.Results and discussion. It has been found that cyclocondensation of N-Boc-4-aminopyrazole-5-carbaldehydes with creatinine can be used as an effective method for obtaining 6-aminoimidazo[4,5-b]pyrazolo[3,4-e]pyridines previously unknown. For the synthesis of their 6-oxoanalogs, the reaction of 5-aminopyrazolo[4,3-b]pyridine-6-carboxylic acids used in a modifed Curtius rearrangement with diphenylphosphorylazide was successful. This method was implemented through the stage of the intermediate aminoisocyanates formation.Experimental part. The reaction of N-Boc-4-aminopyrazole-5-carbaldehydes with creatinine in the presence of pyrrolidine as a catalyst in refluxing acetic acid allowed to obtain 6-aminoimidazo[4,5-b]pirazolo[3,4-e]pyridines with the yields of 54 – 70 %. The structure of the compounds synthesized was proven by spectral measurements. In the 1H NMR spectra there were singlets of H-3 (7.63 – 7.88 ppm) and H-8 (7.87 – 8.26 ppm) protons, as well as broad singlets of the NH2 group in the range of 7.05 – 7.21 ppm. Heating of 5-aminopyrazolo[4,3-b]pyridine-6-carboxylic acids with triethylamine and diphenylphosphorylazide in dioxane for 6 hours gave 1-substituted imidazo[4,5-b]pyrazolo[3,4-е]pyridine-6(5Н)-ones with the yields of 67 – 80 %. The IR-spectra of the compounds synthesized were characterized by the absorption bands of the C=O (1705 – 1708 cm-1) and NH (3275 – 3281 cm-1) groups. 1H NMR-spectra were characterized by singlets of H-3 and H-8 protons in the intervals of 7.43 – 8.08 ppm and 7.92 – 8.32 ppm respectively, as well as by two broad singlets of NH-protons in the ranges of 10.90 – 11.12 ppm and 11.25 – 11.37 ppm.Conclusions. Effective approaches to the synthesis of new promising heterocyclic systems of 6-amino- and6-oxoimidazo[4,5-b]pirazolo[3,4-e]pyridines have been developed. Cyclocondensations of N-Boc-4-aminopyrazole-5-carbaldehydes with creatinine and 5-aminopyrazolo[4,3-b]pyridine-6-carboxylic acids with diphenylphosphorylazide have been proven to be convenient ways to obtain these compounds with good yields.Key words: N-Boc-4-aminopyrazole-5-carbaldehyde; creatinine; 5-aminopyrazolo[4,3-b]pyridine-6-carboxylic acid; diphenylphosphorylazide; 6-amino(oxo)imidazo[4,5-b]pyrazolo[3,4-e]pyridines;cyclocondensation

scholarly journals Conjugation of thiol-terminated molecules to ultrasmall 2 nm-gold nanoparticles leads to remarkably complex 1H-NMR spectra

2016 ◽  
Vol 4 (12) ◽  
pp. 2179-2189 ◽  
Author(s):  
Benjamin Schuetze ◽  
Christian Mayer ◽  
Kateryna Loza ◽  
Martin Gocyla ◽  
M. Heggen ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Carboxylic Acids ◽  
1H Nmr ◽  
Nmr Spectra ◽  
1H Nmr Spectra ◽  
Small Peptides

Gold nanoparticles, functionalized by aliphatic and aromatic mercapto-functionalized carboxylic acids and by two small peptides (CG and CGGRGD), respectively, were synthesized by the reduction of HAuCl4 with NaBH4 in the presence of the above ligands.

SYNTHESIS, CHARACTERISATION AND ANTIFUNGAL ACTIVITYOF SOME NEWLY SYNTHESISED POLYSUBSTITUTED PYRAZOLES

INDIAN DRUGS ◽  
2017 ◽  
Vol 54 (10) ◽  
pp. 23-29
Author(s):  
A. Kumar ◽  
◽  
C. P. Singh
Keyword(s):  
Acetic Acid ◽  
Biological Activity ◽  
Antifungal Activity ◽  
Formic Acid ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Acid Hydrazide ◽  
1H Nmr Spectra ◽  
Aryl Aldehyde

A novel series of polysubstituted pyrazoles were synthesised by the cyclization of (α phenoxy/octyl) acetyl aryl hydrazones in presence of formic acid, by refluxing (α-phenoxy/octyl) acetic acid hydrazide and substituted aryl aldehyde, using C2H5OH as solvent. The newly synthesised compounds were characterised by IR, 1H NMR spectra and also screened for their promising biological activity i.e. antifungal activity.

scholarly journals Eu(fod)3 EFFECT ON 1H NMR SPECTRA OF 3-ARYLISOCOUMARINS AND 3-ARYL-3,4-DIHYDROISOCOUMARINS WITH ALKOXY, ESTER AND AMIDE GROUPS

2017 ◽  
pp. 74-80
Author(s):  
V. Khilya ◽  
O. Shablykina ◽  
M. Tsapko ◽  
S. Shilin ◽  
V. Moskvina ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Methyl Ester ◽  
Oxygen Atom ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Shift Reagent ◽  
1H Nmr Spectra ◽  
Aromatic Substituent ◽  
Phenoxy Acetic Acid ◽  
Hydroxyacetic Acid

The effect of the lanthanide shift reagent (LSR) – tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octa-dionate) of Europium – Eu(fod)3 – on 1H NMR spectra of functionalized 3-arylisocoumarins and 3-aryl-3,4-dihydroisocoumarins was investigated. Based on previous studies of LSR interactions with benzopyrones, it was expected that the main coordination centre for the Eu3+ would be the exocyclic Oxygen atom of the heterocycle, but the possibility of competition from aromatic substituent functional groups was also considered. By measuring lanthanide-induced shifts (LIS) of the proton signals of the molecules at different ratios of substrate and Eu(fod)3, specific LIS values were determined. Based on those, it was concluded that the main direction of LSR coordination with 3-(2-hydroxy-5-methylphenyl)-1Hisochromen-1-one, 3-(2-methoxy-5-methylphenyl)-1H-isochromen-1-one and 3-(2-methoxy-5-methylphenyl)isochroman-1-one is the exocyclic Oxygen atom of the heterocycle, because the maximum LIS were recorded for the H-8 atom of isochromone system of these derivatives. In the case of ethyl ester of [2-(4-(1-oxo-1H-isochromen-3-yl)phenoxy] acetic acid and methyl ester of [2-(4-(1-oxoisochroman-3-yl)phenoxy]acetic acid comparable LIS values were observed both for H-8 and for the methylene group of the hydroxyacetic acid fragment, therefore, in such molecules the coordination of the Eu3+ to the heterocycle or to the aliphatic ester group is almost equally probable. In spectrum of methyl ester of N-{[4-(1-oxo-1H-isochromen-3-yl)phenoxy]acetyl}valine and N-{[4-(1-oxoisochroman-3-yl)-phenoxy]acetyl}valine there are insignificant LIS of H-8; and the maximum LIS were observed for the signals of the protons neighboring the two carbonyl groups of hydroxyacetic acid and valine fragments. Thus, these compounds interact w

SYNTHESIS OF BENZOFURAN-5,6-DICARBONITRILES ANNELATED WITH PYRAZOLE CYCLE

2017 ◽  
Vol 60 (6) ◽  
pp. 45
Author(s):  
Zhanna V. Chirkova ◽  
Sergey I. Filimonov ◽  
Igor G. Abramov
Keyword(s):  
Ir Spectra ◽  
Hydrazine Hydrate ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Pyrazole Ring ◽  
Aldehyde Group ◽  
1H Nmr Spectra ◽  
Synthetic Methods ◽  
Carbonyl Groups ◽  
Principal Method

The principal method for the preparation of substituted 4-formyl-1H-pyrazoles was the treatment of hydrazones of different structure with Vilsmeier-Haack reagent. However, for the heterocyclic benzofuran system this reaction is rarely used. Synthetic methods for preparation of novel substituted 3-(4-fomyl-1H-pyrazole-3-yl)-2-methylbenzofuran-5,6-dicarbonitriles and 2-(1H-pyrazole-4-yl)-benzofuran-5,6-dicarbonitriles were developed by modification of 2,3-disubstituted benzofuran-5,6-dicarbonitriles via Vilsmeier-Haack reaction. New substituted 3-(4-fomyl-1H-pyrazole-3-yl)-2-methylbenzofuran-5,6-dicarbonitriles were obtained by reacting 3-acetyl-2-methyl-1-benzofuran-5,6-dicarbonitrile with hydrochloric substituted phenylhydrazines followed by treatment with the Vilsmeier reagent formed hydrazones. A new method for the synthesis of 3-substituted 2-(1H-pyrazol-4-yl)-benzofuran-5,6-dicarbonitriles was based on condensation of aminovinylbenzofuranes with hydrazine hydrate in refluxing acetic acid. The structure of synthesized compounds was determined by data of the IR and NMR spectroscopy, including two-dimensional correlation 1H-1H spectroscopy, and mass spectrometry. The signals of cyano and formyl groups were characteristic in IR spectra; the signals of phthalonitrile protons and proton of aldehyde group - in 1H NMR spectra for 3-(4-formyl-1H-pyrazole)-2-methyl-1-benzofuran-5,6-dicarbonitriles. Also, structure of synthesized 4-formylpyrazoles is confirmed by their reaction with hydrazine hydrate to give corresponding hydrazones. The signals of NH-pronon of pyrazole ring, cyano and carbonyl groups were characteristic in IR spectra; signal broadened singlet of NH-proton of pyrazole ring, which determined to prototropic ring tautomerism of pyrazole ring, and singlets of phthalonitrile protons - in 1H NMR spectra for 3-substituted 2-(1H-pyrazol-4-yl)-benzofuran-5,6-dicarbonitriles. Development of methods for the synthesis of new 4-formylpyrazoles is an important task because the compounds exhibit various pharmacological properties: antimicrobial, anti-inflammatory, antituberculosis, antitumoral, antiparasitic, and antiviral.Forcitation:Chirkova Zh.V., Filimonov S.I., Abramov I.G. Synthesis of benzofuran-5,6-dicarbonitriles annelated with pyrazole cycle. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 6. P. 45-51. 

scholarly journals Synthesis and biological studies for some heterocyclic compounds derived from 2-Morpholino-1,8- naphthyridine-4-carboxylic acid

2013 ◽  
Vol 10 (3) ◽  
pp. 758-765 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Carboxylic Acid ◽  
1H Nmr ◽  
Heterocyclic Compounds ◽  
Nmr Spectra ◽  
1H Nmr Spectra ◽  
Starting Material ◽  
Good Activity ◽  
Biological Studies

New heterocyclic compounds derived from 2-Morpholino-1,8-naphthyridine-4-carboxylic acid such as oxadiazolo, thiadiazolo – thione and triazolo-thione have been prepared and characterized on the basis of IR and 1H NMR spectra data. The hydrizide compound was utilized as a starting material for preparing of these compounds. The second part of this study involves the biological studies of some of these naphthyridine derivatives by using three different kinds of bacteria namely: Staphylococcus aureus, Pseudomonas aeruglnosa and Escherichia coli. The data indicated that some of these compounds have a good activity against the tested bacteria in comparison to antibiotics.

1H NMR spectra of 1-alkyl-1,2,3,4-tetrahydro-2-oxo-3-azocine-carboxylic acid derivatives and their analogues

Tetrahedron ◽  
1980 ◽  
Vol 36 (1) ◽  
pp. 81-85 ◽  
Author(s):  
K. Somekawa ◽  
S. Kumamoto ◽  
T. Matsuo ◽  
I. Ueda
Keyword(s):  
Carboxylic Acid ◽  
1H Nmr ◽  
Nmr Spectra ◽  
1H Nmr Spectra

scholarly journals Synthesis of 5-aryl-3-hydroxy-1-(2-hydroxypropyl)-4-(furyl-2-carbonyl)- 3-pyrrolin-2-ones and 5-aryl-3-hydroxy-1-(3-hydroxypropyl)- 4-(furyl-2-carbonyl)-3-pyrrolin-2-ones

2020 ◽  
Vol 63 (9) ◽  
pp. 26-30
Author(s):  
Daria D. Rubtsova ◽  
◽  
Alexandra A. Bobyleva ◽  
Daria D. Lezhnina ◽  
Sofia V. Polikarpova ◽  
...  
Keyword(s):  
Biological Activity ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Research Work ◽  
Chemical Properties ◽  
Methine Proton ◽  
1H Nmr Spectra ◽  
Biologically Active ◽  
Hydroxyl Group ◽  
Derivatives Of

In this work, pyrrolidin-2-ones and their derivatives are considered as a promising class of non-aromatic heterocyclic compounds. Their structure is found in the nuclei of many natural products and biologically active molecules. In pharmacy the possibility of introducing various substituents into the nucleus of pyrrolidin-2-ones is a great importance for the synthesis of new medicinal molecules with improved biological activity. Nowadays the synthesis of new active compounds by introducing various substituents at the C1-, C4- and C5-position of 3-hydroxy-3-pyrrolin-2-one has been little studied and it is of great interest to study the conditions of their synthesis, chemical properties and biological activity. In this research work the corresponding 5-aryl-3-hydroxy-1-(2-hydroxypropyl)-4-(furyl-2-carbonyl)-3-pyrrolin-2-ones and 5-aryl-3-hydroxy-1-(3-hydroxypropyl)-4-(furyl-2-carbonyl)-3-pyrrolin-2-ones were synthesized by the reaction of methyl ester of furyl-2-carbonylpyruvic acid with a mixture of aromatic aldehyde and 1-amino-2-hydroxypropane or 3-amino 1-hydroxypropane when heated in dioxane. The results of the study of the structure of the new synthesized compounds are presented. The structure was proved using 1H NMR spectroscopy and IR spectrometry. It was shown that the IR spectra of the compounds contain bands of the corresponding stretching vibrations of the alcoholic hydroxyl group, enol hydroxyl, amide and ketone groups. In the 1H NMR spectra of the compounds, along with the signals of aromatic protons in the C5 substituent and related groups, characteristic peaks are observed, indicating the formation of the corresponding derivatives of 3-hydroxy-3-pyrrolin-2-ones. It was noted that in the case of the synthesis of 5-aryl-3-hydroxy-1-(2-hydroxypropyl)-4-(furyl-2-carbonyl)-3-pyrrolin-2-ones, the signal of the methine proton at the C5 position of the heterocycle is cleaved in 1H NMR spectra compounds as a result of the appearance of a second chiral center in the 2-hydroxypropyl radical. Elemental analysis was performed for the synthesized compounds.

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