Electrooxidative Conversion of Dibenzoylbenzene Dihydrazones into the Corresponding Bis-diazo Compounds and Bis-dimethyl Acetals

2005 ◽  
Vol 58 (7) ◽  
pp. 560 ◽  
Author(s):  
Mitsuhiro Okimoto ◽  
Kaori Numata ◽  
Kenta Tomozawa ◽  
Takamasa Shigemoto ◽  
Masayuki Hoshi ◽  
...  
Keyword(s):  
Sodium Methoxide ◽  
Diazo Compound ◽  
Catalytic Amount ◽  
Diazo Compounds ◽  
Purple Colour ◽  
Methanolic Solution

Several dibenzoylbenzene dihydrazones were electrochemically oxidized into the corresponding bis-dimethyl acetals in a methanolic solution containing sodium methoxide and a catalytic amount of KI. During electrolysis, the anolyte exhibited a characteristic deep purple colour, which strongly suggests the formation of a diazo compound as an intermediate. Such intermediates have been isolated in the electrooxidation of two dihydrazones.

Aliphatic diazo compounds. X. The reaction of α-diazoacetophenone with methanolic sodium methoxide

1977 ◽  
Vol 55 (1) ◽  
pp. 145-152 ◽  
Author(s):  
Peter Yates ◽  
R. J. Mayfield
Keyword(s):  
Acrylic Acid ◽  
Benzoic Acid ◽  
Sodium Methoxide ◽  
Methyl Benzoate ◽  
Diazo Compounds ◽  
Dilute Solution ◽  
Cis And Trans

The reaction of α-diazoacetophenone (1) with methanolic sodium methoxide in dilute solution gives 3-benzoyl-5-hydroxy-4-phenylpyrazole (4), 3-benzoyl-4-hydroxy-5-phenyl-pyrazole (5), 3-benzoyl-5-methoxy-4-phenylpyrazole (9), 3-benzoyl-4-phenylpyrazole (6), 5-benzoyltetrazole (7), 3,6-dibenzoyldihydro-s-tetrazine (10), cis- and trans- β-benzoyl- α-phenyl-acrylic acid, acetophenone, methyl benzoate, and benzoic acid. The pyrazoles 4, 5, and 9 are considered to arise via reaction of 1 to give α-methoxyacetophenone followed by further reaction of the anion of the latter with 1. Evidence in accord with this view was obtained by a study of the products formed when 1 was treated with methanolic sodium methoxide in the presence of 2-methoxy-4′-methylacetophenone. Acetophenone is considered to arise by reduction of 1 via phenylglyoxal 2-monohydrazone (37); condensation of 1 with the enolate ion derived from acetophenone then can give the pyrazole 6, while condensation of 1 with 37 could give the tetrazole 7.

4-β-D-Ribofuranosyl-1,2,4-triazin-3,5(2H,4H)-dione and 4-β-D-ribofuranosyl-6-methyl-1,2,4-triazin-3,5(2H, 4H)-dione

1982 ◽  
Vol 47 (3) ◽  
pp. 994-999 ◽  
Author(s):  
Hubert Hřebabecký
Keyword(s):  
Uv Irradiation ◽  
Sodium Methoxide ◽  
Methanolic Solution ◽  
Acid Catalyzed ◽  
Methyl Pyruvate

4-β-D-Ribofuranosyl-1,2,4-triazin-3,5(2H,4H)-dione (IX) and 4-β-D-ribofuranosyl-6-methyl-1,2,4,-triazin-3,5(2H,4H)-dione (XI) were prepared by cyclization of (Z)-4-β-D-ribofuranosyl-semicarbazones of methyl glyoxylate (VI) and methyl pyruvate (VIII) in the methanolic solution of sodium methoxide. A mixture of (E)- and (Z)-ribosylsemicarbazones III and IV was prepared by condensation of the ribosylsemicarbazide I with methyl dimethoxyacetate and a mixture of (E)-and (Z)-isomers V and VIII was obtained on condensation of I with methyl pyruvate. The (Z) isomer VI was prepared on acid-catalyzed isomerisation of the (E)-isomer III while the (Z)-isomer VIII was obtained on the UV-irradiation of isomer V.

CARBONYL AND THIOCARBONYL COMPOUNDS: X. SYNTHETIC EXPERIMENTS WITH COUMARIN-2-THIONE AND BENZOXANTHIONES

1966 ◽  
Vol 44 (9) ◽  
pp. 1075-1081 ◽  
Author(s):  
N. Latif ◽  
I. Fathy
Keyword(s):  
Hydrazine Hydrate ◽  
Diazo Compound ◽  
Diazo Compounds ◽  
Cyclopropane Derivative ◽  
Cyanoacetic Ester

The benzoxanthene ethers Ia–IIb are obtained in good yields by the action of tetrachloro-and tetrabromo-o-benzoquiuone on 1,2- and 3,4-benzoxanthione, respectively. The benzopyran analogues IIIa–IIIb are obtained by the interaction of the corresponding haloquinone and coumarin hydrazone. The latter, which is now readily obtained by the action of hydrazine hydrate on coumarin-2-thione, condenses with thioketones to give coumarin azines. The benzopyran ethers IIIa and IIIb are cleaved by malononitrile, cyanoacetic ester, hydrazine hydrate, phenylhydrazine, and benzoylhydrazine, yielding the unsaturated nitriles (Va–Vb) and the corresponding hydrazones, respectively.1,2-Benzoxanthione reacts with 9-diazoxanthene, diphenyldiazomethane, and diphenylenediazomethane to give the ethylene sulfides VI–VIII, respectively. However, coumarin-2-thione reacts with the diazo compounds in a different manner; it gives the ethylenes X and XI directly, together with the symmetrical thiiranes XII and XIII, in the cases of diphenyldiazomethane and 9-diazoxanthene, respectively, whereas the cyclopropane derivative XIV is produced in the case of diphenylenediazomethane. XIV is also obtained by the photochemical interaction of coumarin itself and the diazo compound.

scholarly journals INTERACTION OF HYDRIDE Σ-COMPLEX OF 5,7-DINITRO-8-HYDROXYQUINOLINE WITH SALTS OF AROMATIC DIAZO COMPOUNDS

2019 ◽  
Vol 62 (11) ◽  
pp. 85-91 ◽  
Author(s):  
Il'ya I. Ustinov ◽  
Nikolay V. Khlytin ◽  
Igor' V. Blokhin ◽  
Irina V. Shakhkel'dyan ◽  
Yuriy M. Atroshchenko ◽  
...  
Keyword(s):  
Diazo Compound ◽  
Coupling Reaction ◽  
Diazo Compounds ◽  
Azo Compounds ◽  
Azo Coupling ◽  
Absorption Bands ◽  
Stretching Vibrations ◽  
Intramolecular Hydrogen ◽  
Yield And Purity ◽  
Mild Acid

Interaction between 5,7-dinitro-8-hydroxyquinoline hydride anionic σ-adduct and chlorides of substituted aryldiazonium in water yielded 5-arylazo-7-nitro-8-hydroxyquinolines, the substitution products of the nitro group at the C-5 σ-adduct position. The direction of the reaction agrees with the quantum-chemical calculations carried out earlier and the GMLA principle, which assumes that the mild acid, which is a diazocathione, will attack the reaction center to which the softest base corresponds, that is, the least negatively charged C-5 carbon atom, in contrast to the C-7 atom. It is shown that the yield of the product increases with the presence of an electron-withdrawing substituent in the diazocomponent. Also in this study, the synthesis of the hydride σ-adduct of 5,7-dinitro-8-hydroxyquinoline was optimized. It was found that the use of pure dimethylacetamide as a solvent, as well as the addition of sodium carbonate, increases the yield and purity of the synthesized σ-adduct. The structure of the obtained compounds was proved by the methods of NMR and IR spectroscopy. In the IR spectra of all synthesized azo compounds, weak absorption bands corresponding to the stretching vibrations of the azogroup (N = N) are fixed in the range of 1400-1465 cm-1, which also indirectly confirms the expected direction of the reaction. Otherwise, the bands of the azogroup vibrations would be shifted to the 1500-1600 cm-1 region as a result of azo-hydrazoic tautomerism. In 1H NMR spectra of synthesized compounds, there is no proton signal of intramolecular hydrogen bond at δ 14-15 ppm, characteristic of the hydrazine form. The proton signals of the arylazo group also confirm the presence of the latter. The use of anionic hydride σ-complexes of dinitroquinoline derivatives as azo-component in the reaction with aromatic diazo compound expands the synthetic possibilities of the azo coupling reaction and allows to obtaine new nitroazoquinolines.

scholarly journals Pd-Catalyzed Dearomative Three-Component Reaction of Bromoarenes with Diazo Compounds and Allylborates

2019 ◽  
Author(s):  
Masaaki Komatsuda ◽  
Hiroki Kato ◽  
Kei Muto ◽  
Junichiro Yamaguchi
Keyword(s):  
Diazo Compound ◽  
Diazo Compounds ◽  
Reaction Conditions ◽  
Three Component Reaction

Acatalytic dearomative three-component reaction of bromoarenes with TMS-diazomethane and allyl borate was developed. The key of this assembling reaction is the use of a diazo compound to generate a Pd-π-benzyl intermediate through a Pd-carbenoid species. This method allowed for a dearomative functionalization using arenes as limiting reagents. Heteroaryl bromides were also applicable to give dearomatized structures under the reaction conditions.

Benzofuran-oxadiazole hybrids: Design, Synthesis and antimicrobial activity studies

2021 ◽  
Vol 25 (9) ◽  
pp. 15-21
Author(s):  
P. Sanjeeva ◽  
B. Subba Rao ◽  
V. Kamala Prasad ◽  
P. Venkata Ramana
Keyword(s):  
Antimicrobial Activity ◽  
Carboxylic Acid ◽  
Sodium Methoxide ◽  
Acetyl Chloride ◽  
Aqueous Ethanol ◽  
Hydroxylamine Hydrochloride ◽  
Catalytic Amount ◽  
Design Synthesis ◽  
Oxadiazole Derivatives ◽  
Synthetic Intermediate

The six benzofuran-oxadiazole derivatives (4a-d) and (5a-b) have been designed, synthesized, characterized and evaluated for antimicrobial activity. The key synthetic intermediate 5-bromo-N'-hydroxybenzofuran -2-carboxamidine (3) was prepared from 5-bromobenzofuran-2-carboxylic acid (1) in two consecutive steps involving reaction with NaN3, in presence of TEA, Xtalfluor-E, PPh3 in dry DCM at 0oC followed by the treatment of resulting carbonitrile (2) with hydroxylamine hydrochloride in presence of sodium methoxide under reflux in aqueous ethanol. Reaction of carboxamidine (3) with different aryl esters in presence of K2CO3 under reflux conditions in toluene afforded 3-(5-bromobenzofuran-2-yl)-5-substituted phenyl-1,2,4-oxadiazoles (4a-d) while the refluxion of a solution of carboxamidine (3) in dichloromethane with chloro/bromo acetyl chloride in presence of TEA and a catalytic amount of HBTU furnished 3-(5-bromobenzofuran-2-yl)-5-(chloromethyl)-1,2,4-oxadia zole (5a) and 3-(5-bromobenzofuran-2-yl)-5-(bromomethyl)-1,2,4-oxadiazole (5b).

scholarly journals DFT investigation on mechanism of dirhodium tetracarboxylate-catalyzed O-H insertion of diazo compounds with H2O

2010 ◽  
Vol 8 (1) ◽  
pp. 223-228 ◽  
Author(s):  
Zhenfeng Liu ◽  
Jianyong Liu
Keyword(s):  
Dft Calculations ◽  
Nucleophilic Addition ◽  
Diazo Compound ◽  
Experimental Results ◽  
Diazo Compounds ◽  
Reaction Pathways ◽  
Insertion Reaction ◽  
Oxonium Ylides ◽  
Oxonium Ylide ◽  
Very High

AbstractThe mechanism of the dirhodium tetracarboxylate-catalyzed O-H insertion reaction of diazomethane and methyl diazoacetate with H2O has been studied in detail using DFT calculations. The rhodium catalyst and a diazo compound couple to form a rhodiumcarbene complex. Of two reaction pathways of the Rh(II)-carbene complex with H2O, the stepwise pathway is more preferable than the concerted one. Formation of a Rh(II) complex-associated oxonium ylide is an exothermal process, and direct decomposition of the ylide gives a very high barrier. The high barriers for the 1,2-H shift of Rh(II) complex-associated oxonium ylides make the ylides become stable intermediates in both reactions, especially for the reactions in solution. Difficulty in formation of a free oxonium ylide supports experimental results, indicating that the Rh(II) complex-catalyzed nucleophilic addition of a diazo compound proceeds via a Rh(II) complex-associated oxonium ylide rather than via a free oxonium ylide.

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