Reaction Of Ketoximes Research Articles

The Reaction of Ketoximes with Hypervalent Iodine Reagents: Beckmann Rearrangement and Hydrolysis to Ketones

AbstractWe investigated the reaction of ketoximes with hypervalent iodine reagents. A combination of PhI(OAc)2 and BF3·Et2O promoted the Beckmann rearrangement of ketoximes, thus yielding the corresponding amides. From a detailed investigation of the reaction, we determined that the Beckmann rearrangement is preceded by acetylation of the hydroxy group of the ketoxime in situ, accelerating the Beckmann rearrangement. We confirmed that the acetylated ketoxime undergoes the Beckmann rearrangement with BF3·Et2O. The reaction of ketoximes with Koser’s reagent [PhI(OH)OTs] in the presence of tetrahydrofuran results in hydrolysis, affording the corresponding ketones in high yields at room temperature.

Hypervalent Iodine-Mediated Beckmann Rearrangement of Ketoximes

We developed a Beckmann rearrangement employing hypervalent iodine reagent under mild conditions. The reaction of ketoxime with hypervalent iodine afforded the corresponding ketone, but premixing of hypervalent iodine and a Lewis acid was effective for promoting Beckmann rearrangement. Aromatic and aliphatic ketoximes were converted into their corresponding amides in good to high yields.

ChemInform Abstract: Iron‐Catalyzed Cyclization of Ketoxime Carboxylates and Tertiary Anilines for the Synthesis of Pyridines.

AbstractA series of 2,4,6‐trisubstituted and 2,4‐disubstituted pyridines is readily prepared by Fe‐catalyzed reaction of ketoximes (I) and (VI) with tertiary amines.

Intramolecular cyclization of O-(3,5-dinitrophenyl) and O-(3-amino-5-nitrophenyl) ketoximes, products of transformations of 1,3,5-trinitrobenzene. The synthesis of nitrobenzo[b]furans and 4-hydroxynitroindoles

O-(3,5-Dinitrophenyl) ketoximes obtained in the reactions of ketoximes with 1,3,5-trinitrobenzene undergo acid-catalyzed cyclization into 2-substituted or 2,3-disubstituted 4,6-dinitrobenzo[b]furans. In analogous cyclization, products of selective reduction of a nitro group in O-(3,5-dinitrophenyl) ketoximes unexpectedly yield, along with 6-amino-4-nitrobenzofurans, 4-hydroxy-6-nitroindoles. The 4-NO2 group is displaced from 4,6-dinitrobenzo[b]furans in reactions with thiols in the presence of K2CO3. Conditions for nitration and sulfochlorination of 4,6-dinitrobenzo[b]furans in position 3 were found. Condensation of a 2-methyl derivative with dimethylformamide acetal was accomplished.

N- tert-Butyl- N-chlorocyanamide: a new reagent for the efficient preparation of gem-chloronitroso compounds

A new reagent for the efficient preparation of gem-chloronitroso compounds has been developed. The reaction of ketoximes with N- tert-butyl- N-chlorocyanamide takes place instantaneously in carbon tetrachloride at room temperature with excellent yields under mild conditions.

A Simple Method for Synthesis of Methylene Dioximes Using Poly(ethylene glycol)‐400 as a Phase Transfer Catalyst.

Abstract A simple method for synthesis of methylene dioximes by reaction of ketoximes with dichloromethane in the presence of aqueous sodium hydroxide solution using poly (ethylene glycol)‐400 (PEG‐400) as a phase transfer catalyst is described.

A Simple Method for Synthesis of Methylene Dioximes Using Poly(ethylene glycol)‐400 as a Phase Transfer Catalyst

A simple method for synthesis of methylene dioximes by reaction of ketoximes with dichloromethane in the presence of aqueous sodium hydroxide solution using poly (ethylene glycol)‐400 (PEG‐400) as a phase transfer catalyst is described.

Site selectivity in the addition of ketoximes to activated allenes and alkynes; N- versus O-alkylation

Reaction of ketoximes with methyl propiolate afforded geometrical isomers of the methyl 3-(hydroxyimino)propanoates 4 and of the O-vinyl oximes 5 as well as the 2-isoxazoline 6. With dimethyl penta-2,3-diendioate 8c reaction progressed via an O-alkylation to give the O-oxime ethers 9, only in the case of cyclopentanone oxime was the spirocyclic dihydroazepinol 11 also obtained, its identity has been confirmed by an X-ray structure determination.

Reaction of ketoximes with aliphatic aldehydes and diphenylborinic acid. Crystal and molecular structure of a diphenylboron chelate derived from the pivaldehyde adduct to cyclohexanone oxime

Various ketoximes have been reacted with aliphatic aldehydes in the presence of oxybis(diphenylborane) in order to assess the influence of increasingly bulky residues on the nature of the products. Crystals of 5-tert-butyl-2-cyclohexylidene-3,3-diphenyl-1,4-dioxa-2-azonia-3-boratacyclopentane, 4c, are monoclinic, a = 14.0647(9), b = 11.416(1), c = 14.756(1) Å, β = 115.696(4)°, Z = 4, space group P21/c. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R = 0.038 (Rw = 0.038) for 2511 reflections with I >= 3σ(I). A bulky substituent at the aldehyde favors α-hydroxyalkylation at the oxime oxygen atom and subsequently leads to the formation of BOCON diphenylboron chelates, whereas formaldehyde reacts by N-alkylation of the oximes, resulting in COBON diphenylboron chelates.Key words: ketoximes, organoboron compounds, crystal structure.

Reaction of ketoximes with aliphatic aldehydes and diphenylborinic acid. Crystal and molecular structure of a diphenylboron chelate derived from the pivaldehyde adduct to cyclohexanone oxime

Reaction of ketoximes with aliphatic aldehydes and diphenylborinic acid. Crystal and molecular structure of a diphenylboron chelate derived from the pivaldehyde adduct to cyclohexanone oxime

Synthesis of (?-substituted ?-aminophosphinic and ?-aminophosphonic acids

The reaction of ketoximes with hypophosphorous acid resulted in previously unknown α-substituted-α-aminophosphinic acids, which were oxidized into the corresponding α-substituted-α-aminophosphonic acids.

The base-catalysed rearrangement of O-propargyl ketoximes to N-1-alkenyl acryl amides

O-Propargyl ketoximes, available from the reaction of ketoximes with propargyl halides in KOH/DMSO system, readily undergo base-catalysed ( t-BuOK in DMSO or THF) rearrangement to N-(1-alkenyl)acrylamides in 15–58 % yields.

Structural studies of organoboron compounds LXIII. Reaction of ketoximes with aldehydes and diphenylborinic acid, and the crystal and molecular structures of two different types of boron chelates and one of the precursor aldehyde adducts

The diphenylboron chelates of ketoxime adducts to formaldehyde and trichloroacetaldehyde (chloral) have been synthesized. The reactions were carried out as three-component one-pot reactions, and also as two-step reactions for the ketoxime chloral adducts, which were isolated and characterized before reaction with oxybis(diphenylborane) to form the diphenylboron chelates. One of the intermediate adducts and two of the diphenylboron chelates have been characterized by X-ray crystallographic analysis. Crystals of O-(2,2,2-trichloro-1-hydroxyethyl)-2-propanonoxime, 8d, are monoclinic, a = 7.010(2), b = 11.832(3), c = 11.684(2) Å, β = 90.48(2)°, Z = 4, space group P21/c; those of 4-isopropylidene-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopentane, 9a, are orthorhombic, a = 11.098(2), b = 15.364(1), c = 8.715(2) Å, Z = 4, space group P212121; and those of 5-trichloromethyl-2-isopropylidene-3,3-diphenyl-1,4-dioxa-2-azonia-3-boratacyclopentane, 10d, are monoclinic, a = 9.164(2), b = 15.304(3), c = 13.859(2) Å, β = 105.28(1)°, Z = 4, space group P21/n. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R = 0.037, 0.044, and 0.040 (Rw = 0.041, 0.016, and 0.042) for 1082, 1256, and 3062 reflections with I ≥ 3σ(F2), respectively. The X-ray analyses show that the products from the reaction between acetonoxime, oxybis(diphenylborane), and formaldehyde or trichloroacetaldehyde, respectively, possess different boron chelate structures. With formaldehyde a COBON chelate ring is obtained and with trichloroacetaldehyde a BOCON chelate ring is formed. Keywords: boron chelates, boron compounds, organboron compounds, crystal structures.

Sulfur-Containing Pyrroles

Abstract The ketoxime-acetylene-based pyrrole synthesis provides two general versatile approaches to sulfur-containing pyrroles: (i) via sulfur-containing ketones, particularly such as acylated aryl sulfides or thiophenes and (ii) via thiylation reactions (including those via metallation) of N-vinylpyrroles or dithiocarbonization of pyrroles available from the reaction of ketoximes with acetylene or its synthetic equivalents. Syntheses of alkylthiopyrroles, alkylthioarylpyrroles, 2-(2-thienyl)pyrroles (and their N-vinyl derivatives), N-(alkylthio or arylthio)ethylpyrroles, pyrrole-1 - and pyrrole-2-dithiocarboxylates (by the reaction of pyrroles with carbon disulfide) and their derivatives such as functionalized 2-(1-alkylthiovinyl)pyrroles, 1-alkylthio-3-imino-3H-pyrrolizines, 1-alkylthio-3H-pyrrolizin-3-ones, are discussed.

Sulfur-Containing Pyrroles

Abstract The ketoxime-acetylene-based pyrrole synthesis provides two general versatile approaches to sulfur-containing pyrroles: (i) via sulfur-containing ketones, particularly such as acylated aryl sulfides or thiophenes and (ii) via thiylation reactions (including those via metallation) of N-vinylpyrroles or dithiocarbonization of pyrroles available from the reaction of ketoximes with acetylene or its synthetic equivalents. Syntheses of alkylthiopyrroles, alkylthioarylpyrroles, 2-(2-thienyl)pyrroles (and their N-vinyl derivatives), N-(alkylthio or arylthio)ethylpyrroles, pyrrole-1 - and pyrrole-2-dithiocarboxylates (by the reaction of pyrroles with carbon disulfide) and their derivatives such as functionalized 2-(1-alkylthiovinyl)pyrroles, 1-alkylthio-3-imino-3H-pyrrolizines, 1-alkylthio-3H-pyrrolizin-3-ones, are discussed.

Further Development of the Ketoxime-based Pyrrole Synthesis

Recent development and modification of the general synthesis of pyrroles and 1-vinylpyrroles by the reaction of ketoximes with acetylenes and their synthetic equivalents (vinyl halides and dihaloalkanes) in the presence of the strongly basic KOH/DMSO catalytic and eliminating pair (the Trofimov reaction) are briefly reviewed. The formation of 3H-pyrroles and other isolable intermediates (O-vinyl ketoximes and hydroxypyrrolines) as well as side products are discussed

Condensation of ketoximes with phenylacetylene

2-Methyl-5-phenyl- and 2,5-diphenylpyrrole and 2-phenyl-, Z-[1-(2-phenylvinyl)]-3-phenyl-, and 4,5,6,7-tetrahydroindole, and 2,4-diphenyl-3,3-dimethyl-5-hydroxypyrroline have been obtained from the reaction of ketoximes with phenylacetylene, catalyzed by KOH-DMSO.

ChemInform Abstract: Isomerization During the Reaction of Ketoximes with Propargyl Ethers.

AbstractIn the presence of KOH the reaction between the oximes (I) and the 2‐propynyl alkyl ethers (II) unexpectedly affords the oximes (IV) instead of the expected alkoxypyrroles.

Synthesis of 2,5-disubstituted pyrroles by the reaction of ketoximes with 1,2-dibromopropane

The reaction of ketoximes with 1,2-dibromopropane in the KOH-DMSO system gave 2,5-disubstituted pyrroles in 21–56% yield.

ChemInform Abstract: REACTION OF KETOXIMES WITH ACETYLENE: NEW GENERAL METHOD FOR THE SYNTHESIS OF PYRROLES (REVIEW)

AbstractReview: In der Übersichtsarbeit wird die Pyrrolsynthese auf der Basis der Umsetzung von Ketoximen mit Acetylenen in Gegenwart starker Basen, insbesondere bezüglich der Reaktionsbedingungen, der Brauchbarkeit der Reaktion zur Herstellung von Vinylpyrrolen, der präparativen Grenzen der Reaktion und des Reaktionsmechanismus eingehend untersucht.