Reaction Of Oximes Research Articles

Synthesis and Anticancer Activity of 2,3,4‐Trimethoxyacetophenoxime Ester Containing Benzothiazole Moiety

AbstractA series of 2,3,4‐trimethoxyacetophenoxime esters containing benzothiazole moiety were synthesized by the reaction of oxime with acyl chloride in alkaline medium. Their structures were established by elemental analysis, IR, and 1H NMR spectra. The bioassay tests showed that these title compounds exhibit moderate anticancer activity in vitro by MTT method and compounds 6c and 6d could inhibit ERK phosphorylation in NIH 3T3 cell induced by PDGF.

New Synthesis and Fungicidal Activity of the Phosphine Analogues of Serine and Threonine.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Phenylhydrazone of 5-Acetyl-3-(Methylsulfanyl)-1,2,4-Triazine and 3-Methyl-5-(Methylsulfanyl)-1-Phenyl-1H-Pyrazolo[4,3-e][1,2,4]Triazine from Pivotal Intermediate

As part of ongoing research programme on bicyclic heterocycles [1,2,3,4] we have elaborated a new approach to 1H-pyrazolo[4,3-e][1,2,4]triazine derivative 3 and its synthetic precursor 2 by reaction of oxime 5-acetyl-3-(methylsulfanyl)-1,2,4-triazine (1) with phenylhydrazine hydrochloride under different reaction conditions.[...]

Microwave promoted oxazole synthesis: cyclocondensation cascade of oximes and acyl chlorides

Microwave irradiation promotes the rapid O, N-acylation–cyclodehydration cascade reaction of oximes and acid chlorides to give oxazoles.

Diastereoselective Synthesis and Antifungal Activity of Glycosyl Isoxazolines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

JIRO TSUJI. Palladium reagents and catalysts: new perspectives for the 21st century. Wiley–VCH, 2004. 670 pp. ISBN 0470850337 (paperback)

JIRO TSUJI. Palladium reagents and catalysts: new perspectives for the 21st century. Wiley–VCH, 2004. 670 pp. ISBN 0470850337 (paperback)

New synthesis and fungicidal activity of the phosphine analogues of serine and threonine

The phosphine analogues of serine and threonine were prepared by the reaction of hydroxyaldehyde oximes with H3PO2, and the acid ester of sulfuric acid and the phosphine analogue of serine was synthesised; the high fungicidal activity of these substances was found for the first time.

Diastereoselective Synthesis and Antifungal Activity of Glycosyl Isoxazolines#

Glycosyl nitrile oxides, generated in situ by reaction of glycosyl oximes (3a, 3b, 4) with N‐chlorosuccinimide and DBU, on 1,3‐dipolar cycloaddition with substituted alkenes resulted in glycosyl isoxazolines (5, 7–28) in diastereoselective manner. The extent of diastereoselection varies with the nature of substituents both in sugar and alkenes. The compounds synthesized were screened in vitro against many fungi wherein two of the compounds (12, 23) showed significant inhibition against Sporothrix schenckii, Trychophyton mentagrophytes, and Cryptococcus neoformans with MIC of 12.5 and 6.25 µg/mL, respectively. #CDRI Communication No.6460.

Synthesis of annelated derivatives of tetrafluoro-10H-imidazo[1,2-b][1,2]benzooxazin-10-one and 2-pentafluorophenylpyrazine 1,4-dioxide by condensation of alicyclic 2-hydroxyamino oximes with pentafluorophenylglyoxal

Reactions of alicyclic 2-hydroxyamino oximes with pentafluorophenylglyoxal afford mixtures of annelated derivatives of 2-pentafluorophenylpyrazine 1,4-dioxide and tetrafluoro- 10H-imidazo[1,2-b][1,2]benzooxazin-10-one. The structures of the latter were established by X-ray diffraction analysis.

Vapor phase Beckmann rearrangement of cyclohexanone oxime over MCM-22

A comprehensive study has been made on the Beckmann rearrangement of cyclohexanone oxime (CHO oxime) to ϵ-caprolactam, catalyzed by MCM-22 under various operating conditions. The distinct identities of MCM-22 were characterized by XRD, SEM, and NH3-temperature programming desorption (NH3-TPD). The acidic strength of MCM-22 is much weaker than those of ZSM-5 and β zeolites with similar SiO2/Al2O3 ratio. It was found that catalytic active sites with moderate acidic strengths are more favorable for the rearrangement reaction. The carbonaceous residues, which contain mainly functional groups with CN bonds, can be effectively removed by purging the H-MCM-22 catalyst with nitrogen gas at higher temperatures in the absence of oxygen. A reaction pathway was proposed which invokes the main rearrangement reaction of CHO oxime accompanied by two side reactions, namely ring opening reaction of ε-caprolactam to form 5-hexenenitrile (5-HEN) (coke precursor) and hydrolysis reaction to form cyclohexanone. The effects of the Pt incorporation and operating conditions, viz temperature, carrier gas, space velocity, feed concentration, solvent etc., on related reaction equilibriums of the reactions involved and ultimately on catalyst stability and product selectivity were discussed.

Vapor phase Beckmann rearrangement of cyclohexanone oxime over MCM-22

A comprehensive study has been made on the Beckmann rearrangement of cyclohexanone oxime (CHO oxime) to ϵ-caprolactam, catalyzed by MCM-22 under various operating conditions. The distinct identities of MCM-22 were characterized by XRD, SEM, and NH3-temperature programming desorption (NH3-TPD). The acidic strength of MCM-22 is much weaker than those of ZSM-5 and β zeolites with similar SiO2/Al2O3 ratio. It was found that catalytic active sites with moderate acidic strengths are more favorable for the rearrangement reaction. The carbonaceous residues, which contain mainly functional groups with CN bonds, can be effectively removed by purging the H-MCM-22 catalyst with nitrogen gas at higher temperatures in the absence of oxygen. A reaction pathway was proposed which invokes the main rearrangement reaction of CHO oxime accompanied by two side reactions, namely ring opening reaction of ε-caprolactam to form 5-hexenenitrile (5-HEN) (coke precursor) and hydrolysis reaction to form cyclohexanone. The effects of the Pt incorporation and operating conditions, viz temperature, carrier gas, space velocity, feed concentration, solvent etc., on related reaction equilibriums of the reactions involved and ultimately on catalyst stability and product selectivity were discussed.

Cyclization of α‐Oxo‐oximes to 2‐Substituted Benzoxazoles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Formation of the Dinitro-3H-pyrazole Derivative of Cycloartemisiaketone Oxime

(3aR*,6aR*)-3,3,5,5-Tetramethyl-3a,6a-dinitro-3a,6a-dihydro-3H-cyclopentano[c]pyrazol-2-oxide was formed by reaction of cycloartemisiaketone oxime [4,4-dimethyl-2-(1-methylethylidene)cyclopentanone oxime] with AcOH and NaNO2 in CHCl3 solution. The structure was solved by x-ray structure analysis.

A Facile Synthesis of 2,5-Dihydroisoxazoles via an Organoselenium-Induced Stereoselective Cyclisation and Deselenylation Reaction

The organoselenium-induced ring-closure reactions of O-allyl oximes give cyclic iminium salts that can be reduced in situ with NaBH4 to produce N-alkyl-4–phenylselenoisoxazolidines; selenoxide syn-elimination follows to form 2, 5-dihydroisoxazoles in good yields.

Aza-Reformatsky-type reaction of alpha-iodomethyl ketone O-alkyl oximes promoted by titanium tetraiodide.

Titanium tetraiodide promotes an aza-Reformatsky-type reaction of alpha-iodomethyl ketone O-alkyl oximes with carbonyl compounds to give beta-hydroxy ketone O-alkyl oximes in good to high yields.

Cyclization of alpha-Oxo-oximes to 2-substituted benzoxazoles.

Reactions of oximes 9, 17, and 19 with electrophiles 15a-f and 24 in the presence of anhydrous potassium carbonate or triethylamine give 2-substituted condensed ring oxazoles 10, 16a-c, 18a-d, 20a-c, and 25 in a new general route to these compounds.

Synthesis of Spiro and Fused Five Membered N -Heterocycles from Alkylidenephosphoranes

Triketoindan-2-oxime reacted readily with ethoxycarbonylmethylene triphenylphosphorane to give mainly the corresponding spiro-pyrrole (38%) along with the fused 1′-hydroxydihydropyrrole (14%), whereas the spiro-dimer (29%) was obtained from the reaction of the oxime with methoxycarbonylmethylenetriphenyl phosphorane in addition to the corresponding 1′-hydroxydihydropyrrole (31%). Conversely, Wittig products, mono-olefin (52%) and diolefin (<7%) along with the reduced substrate (10%), were observed when the oxime was treated with a cyano ylide. The reactions of the oxime with allyl- and vinyl phosphonium salts proceeded under phase-transfer catalysis to afford fused oxazole (46%) and spiro[2]oxazole (17%), while with the latter the fused 1′-hydroxypyrrole (55%) was produced.

Substituent effects in oxime radical cations. 1. Photosensitized reactions of acetophenone oximes

A variety of ortho-, meta-, and para-substituted (-H, -F, -Cl, -CF3, -CN (meta and para only), -CH3, -OCH3, and -NO2) acetophenone oximes were synthesized and studied using laser flash photolysis (LFP) and steady-state photolysis experiments in acetonitrile with chloranil as the photosensitizer. In addition, semi-empirical (AM1) calculations were performed on the neutral species, the radical cations, and the corresponding iminoxyl radicals. The data was analyzed in terms of the electrochemical peak potentials of the oximes, the quenching rates of triplet chloranil (LFP), the calculated ionization potentials, and the measured conversions of the oximes in the steady-state photolysis experiments. Photolysis of the oximes in the presence of chloranil results in the formation of the chloranil radical anion, which reacts rapidly with the oxime radical cation to form the semiquinone radical and an iminoxyl radical. Evidence for the formation of the chloranil radical anion and the semiquinone radical was obtained from LFP studies. The measured quenching rates from the LFP studies represent the rates of electron transfer from the oximes to triplet chloranil. This data was correlated to various radical and polar substituent constants. The Hammett studies suggest that steric, polar, and radical effects are important for ortho-substituted acetophenone oximes, polar effects are important for para-substituted oximes, and radical stabilization is more important than polar effects for the meta-substituted substrates. The calculated ionization potentials of the oximes show an excellent correlation with the measured quenching rates supporting the electron transfer pathway. On the basis of calculated charge densities, we conclude that the measured substituent effects are transition state effects rather than ground state effects. At this point all of the available data suggests that the conversion of the oximes is controlled by two energetically opposing reactions, namely oxidation of the neutral oxime, which is favorable for oximes with electron-donating substituents, and deprotonation of the oxime radical cation, which is favorable for oximes with electron-withdrawing substituents. The overall result is a reaction with little selectivity as far as substituent effects are concerned.Key words: oxime, radical cation, iminoxyl radical, electron transfer, substituent effect.

Beckmann Reaction of Oximes Catalyzed by Chloral: Mild and Neutral Procedures.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Carbamoylformhydroxymoyl Chlorides and Study of Their Reactivities.

AbstractFor Abstract see ChemInform Abstract in Full Text.