- Synthesis and characterization of novel five-membered heterocycles and their activity against Candida yeasts
-
Some new tetrazole derivatives were prepared by the reaction between the prepared azomethine compounds I6–I10 with sodium azide in anhydrous tetrahydrofuran (THF) with a few drops of distilled water and under reflux conditions. Azome
- Tawfeeq, Hiba Maher,Muslim, Rasim Farraj,Abid, Obaid Hasan,Owaid, Mustafa Nadhim
-
p. 552 - 559
(2019/10/14)
-
- Correlation analysis of reactivity in the oxidation of substituted benzyl alcohols by benzimidazolium dichromate - A kinetic and mechanistic aspects
-
The oxidation of a number of para- and meta-substituted benzyl alcohols by benzimidazolium dichromate (BIDC), in dimethyl sulphoxide, leads to the formation of the corresponding benzaldehydes. The reaction is first order with respect to each BIDC and alcohol. The reaction is catalyzed by hydrogen ions and the dependence has the form kobs = a + b[H+]. The oxidation of [1,1-2H2]benzyl alcohol exhibited the presence of a substantial kinetic isotope effect. The rates of the oxidation of meta-substituted benzyl alcohols correlated best with Taft's σ1 and σR0 constants. The para-substituted compounds exhibited excellent correlation with σ1 and σRBA values. The polar reaction constants are negative. The rate of oxidation of benzyl alcohol was determined in nineteen organic solvents. An analysis of the solvent effect by multiparametric equations indicated the greater importance of the cation-solvating power of the solvents. Suitable mechanisms have been discussed.
- Kumar, Pravesh,Panday, Dinesh,Kothari, Seema
-
p. 1207 - 1215
(2020/06/27)
-
- Synthesis and antifungal activity of diaryl hydrazones from 2,4-dinitrophenylhydrazine
-
A new series of diarylhydrazones derived from 2,4-dinitrophenylhydrazine were synthesized via condensation with aromatic aldehydes whose structures have been determined by mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance spectra. Y
- Ortiz, Sergio,Nelson, Ronald,Kesternich, Víctor,Pérez-Fehrmann, Marcia,Christen, Philippe,Marcourt, Laurence
-
p. 3081 - 3084
(2016/11/17)
-
- An efficient partial reduction of α,β-unsaturated esters using DIBAL-H in flow
-
The partial reduction of α,β-unsaturated esters and benzoate derivatives to form the corresponding aldehydes was achieved using a flow reactor system within 1 s at a high flow rate (18 mL min-1) under cryogenic conditions (-97°C). Commercially available diisobutylaluminium hydride (DIBAL-H) was used as the reductant. The desired enals and benzaldehyde derivatives, except for 4-methoxycinnamate and 4-methoxybenzoate, were formed selectively and redox economically in moderate to high yields.
- Yoshida, Masahito,Otaka, Hiroyuki,Doi, Takayuki
-
p. 6010 - 6016
(2015/03/30)
-
- Structure-Reactivity correlation in the oxidation of substituted benzaldehydes by tetraethylammonium chlorochromate
-
Oxidation of 36 monosubstituted benzaldehydes by tetraethylammonium chlorochromate in dimethyl sulphoxide, leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to chlorochromate and aldehydes. The reaction is promoted by H+; the H+ dependence has the form kobs = a + b[H+]. The oxidation of duteriated benzaldehyde exhibits substantial primary kinetic isotope effect. The reaction was studied in 19 different organic solvents and the effect of solvent was analyzed using Taft's and Swain's multiparametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraperametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta- substituted compounds, which display a greater dependence on the field effect. The positive value of h suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the orthosubstituents. A suitable mechanism has been proposed.
- Gehlot,Prasadrao,Sharma
-
experimental part
p. 1173 - 1178
(2012/01/05)
-
- Studies on the kinetics of tripropylammonium fluorochromate oxidation of some aromatic alcohols in non-aqueous media
-
The oxidation of benzyl alcohol (BnOH) and a few para-substituted benzyl alcohols by tripropylammonium fluorochromate (TriPAFC) in dimethylsulphoxide (DMSO) leads to the formation of corresponding aldehydes. The reaction is first order each in TriPAFC and the alcohols. The reaction is catalysed by hydrogen ions. The hydrogen ion dependence has the form: kobs = a + b[H +]. The oxidation of α α′-dideuterio benzyl alcohol exhibited a substantial primary kinetic isotope effect (kH/k D = 5.45 at 303 K). Oxidation of benzyl alcohol was studied in 19 different organic solvents. The solvent effect has been analysed using Kamlet's and Swain's multiparametric equation. A mechanism involving a hydride ion transfer via chromate ester is proposed.
- Mansoor, S. Sheik,Shafi, S. Syed
-
-
- EXCHANGE REACTIONS OF SUBSTITUTED BENZALDEHYDE HYDRAZONES
-
Hydrazones IV, derived from substituted benzaldehydes and N-aminophthalimide, experience an exchange reaction with one equivalent of 2,4-dinitrophenylhydrazine under conditions free of added mineral acid to cleanly and irreversibly produce the related 2,4-dinitrophenylhydrazones V in good yields.Although literature melting points for compounds V may vary from one reference to another, the infrared spectra (ν (mull), cm-1; IV: 1770, 1710; V: 3280, 1615, 1580, 1510) of starting materials and products in the exchange process are strikingly different and permit ready characterization.
- Hearn, Michael J.,Sy, Karen Grace
-
p. 339 - 342
(2007/10/02)
-
- Kinetics and Mechanism of the Oxidation of Substituted Benzylamines by N-Chlorosuccinimide
-
The oxidation of ortho-, meta-, and para-substituted benzylamines by N-chlorosuccinimide (NCS), to the corresponding benzaldehydes, is first-order with respect to NCS and the amine.The pH dependence of the reaction rate suggests that the unprotonated benzylamine is the reductant.There is no effect of added succinimide.NCS itself has been postulated as the reactive oxidising species.The oxidation of benzylamine exhibited a substantial primary kinetic isotope effect (kH/kD=6.20).The rates of oxidation of the meta- and para-substituted benzylamines were separately correlated in Taft and Swain's dual substituent parameter equations.For the para-substituted compounds, the best correlation is obtained with ?I and ?R+ values; meta-substituted compounds correlate with ?I and ?R0 values.The reaction constants have negative values.The oxidation rates of the ortho-substituted compounds yield an excellent correlation in a triparametric equation involving Taft's ?I and ?R+ values and Charton's steric parameter, V.A mechanism involving transfer of a hydride ion from the amine to the oxidant in the rate-determining step is proposed.
- Banerji, Kalyan K.
-
p. 1015 - 1020
(2007/10/02)
-