10342-64-0Relevant articles and documents
Solid-phase synthesis of oximes
Hajipour,Mohammadpoor-Baltork,Nikbaghat,Imanzadeh
, p. 1697 - 1701 (1999)
In an extremely fast, high efficient and novel method, the reaction of hydroxylamine hydrochloride with a number of aldehydes and ketones under solventless 'dry' condition gave oximes in quantitative yield.
Quinone-sensitized steady-state photolysis of acetophenone oximes under aerobic conditions: Kinetics and product studies
Park, Adriana,Kosareff, Nicole M.,Kim, Jason S.,De Lijser, H. J. Peter
, p. 110 - 118 (2006)
Oxidation of oximes via photosensitized electron transfer (PET) results in the formation of the corresponding ketones as the major product via oxime radical cations and iminoxyl radicals. The influence of electron-releasing and electron-accepting substituents on these reactions was studied. The observed substituent effect strongly supports formation of iminoxyl radicals from the oximes via an electron transfer-proton transfer sequence rather than direct hydrogen atom abstraction. Correlation of the relative conversion of the oximes with Hammett parameters shows that radical effects dominate for the meta-substituted acetophenone oximes (ρrad/ ρpol = 5.4; r2 = 0.93), whereas the para-substituted oximes are influenced almost equally by radical and ionic effects (ρrad/ ρpol = -1.1; r2 = 0.98). From these data sets we conclude that the follow-up reactions proceed through a number of intermediates with both radical and ionic character. This was confirmed by product studies with the use of an isotopically labeled nucleophile. In addition to the major oxidation product (ketone), a chlorine-containing product was often identified as well. Studies on the formation of this product show that the most likely pathway is either via a direct nucleophilic addition in a complex formed between the oxime radical cation and the chloranil radical anion or via a radical substitution (SH2) mechanism. These studies show that with the increasing use of oximes as drugs and pesticides, intake of these chemicals followed by enzymatic oxidation may result in the formation of a variety of reactive intermediates, which may lead to cell and tissue damage.
In situ functionalized sulfonic copolymer toward recyclable heterogeneous catalyst for efficient Beckmann rearrangement of cyclohexanone oxime
Li, Difan,Mao, Dan,Li, Jing,Zhou, Yu,Wang, Jun
, p. 125 - 133 (2016)
Exploring environmentally friendly, efficient and recyclable heterogeneous catalysts for low-temperature liquid-phase organic reactions are important for the development of green and sustainable processes. In this work, we applied an in situ sulfonated polymeric solid acid H-PDVB-SO3H for catalyzing liquid-phase Beckmann rearrangements for the first time, with post-sulfonated sample and other various counterparts as control catalysts. H-PDVB-SO3H was prepared by copolymerization of divinylbenzene with sodium p-styrene sulfonate under solvothermal condition, followed by ion-exchanging to convert the polymer into proton form. It possessed a large surface area, plenty of mesopores and high sulfur content, and exhibited the high yield to ε-caprolactam (75%) with quite steady reusability in the heterogeneous Beckmann rearrangement of cyclohexanone oxime. The catalyst also showed good substrate compatibility with such a high reaction rate that the reaction time was as short as 1 h. No any co-catalysts or metals were used in the catalytic system, making the catalyst an environmentally friendly and efficient candidate for Beckmann rearrangements.
Rhodium(III)-Catalyzed Direct C-H Arylation of Various Acyclic Enamides with Arylsilanes
Li, Xiaolan,Sun, Kai,Shen, Wenjuan,Zhang, Yong,Lu, Ming-Zhu,Luo, Xuzhong,Luo, Haiqing
supporting information, p. 31 - 36 (2021/01/09)
The stereoselective β-C(sp2)-H arylation of various acyclic enamides with arylsilanes via Rh(III)-catalyzed cross-coupling reaction was illustrated. The methodology was characterized by extraordinary efficacy and stereoselectivity, a wide scope of substrates, good functional group tolerance, and the adoption of environmentally friendly arylsilanes. The utility of this present method was evidenced by the gram-scale synthesis and further elaboration of the product. In addition, Rh(III)-catalyzed C-H activation is considered to be the critical step in the reaction mechanism.
Trifluoroacetic Acid Hydroxylamine System as Organocatalyst Reagent in a One-Pot Salt Free Process for the Synthesis of Caprolactam and Amides of Industrial Interest
Manente,Pietrobon,Ronchin,Vavasori
, p. 3543 - 3549 (2021/03/30)
In this work we studied the reactivity of the Trifluoroacetic acid hydroxylamine system in the one step salt free synthesis of amides from ketones. A particular regards was paid to the caprolactam synthesis because of its industrial relevance. Synthesis, reactivity and characterization of the hydroxylamine trifluoroacetate is given. Fast oximation reaction of several ketones was gained at room temperature (1?h of reaction quantitative conversion for several ketones). In the same reactor, by raising the temperature at 383?K, the Beckmann rearrangement of the so obtained oximes is easily accomplished in the presence of three equivalent of TFA. The possibility of obtaining the trifluoroacetate of the hydroxylamine with a modified nitric acid hydrogenation reactions was verified, too. Reuse of solvent and trifluoroacetic acid is easily achieved by distillation. Graphical abstract: Salt free one-pot caprolactam and amides process catalyzed by CF3COOH, in the presence of NH2OH TFA as the oximation agent.[Figure not available: see fulltext.].
Access to pyrrolo[2,1-: A] isoindolediones from oxime acetates and ninhydrin via Cu(i)-mediated domino annulations
Upare, Atul,Chouhan, Neeraj Kumar,Ramaraju, Andhavaram,Sridhar, Balasubramanian,Bathula, Surendar Reddy
supporting information, p. 1743 - 1746 (2020/03/17)
A copper-mediated domino condensation reaction of readily accessible oxime acetates with ninhydrin is reported to afford pyrrolo[2,1-a]isoindolediones via new C-C & C-N bond formations. A wide range of oxime acetates were shown to generally participate in the reaction to produce the condensed products in excellent yields. The necessary control experiments were performed and the mechanism is proposed to involve sequentially the formation of iminium radical via Cu-mediated N-O bond cleavage of oxime acetates, addition of the radical to ninhydrin and rearrangement via ring expansion.
Copper-Catalyzed Annulation of Oxime Acetates with α-Amino Acid Ester Derivatives: Synthesis of 3-Sulfonamido/Imino 4-Pyrrolin-2-ones
Miao, Chun-Bao,Zheng, An-Qi,Zhou, Li-Jin,Lyu, Xinyu,Yang, Hai-Tao
supporting information, p. 3381 - 3385 (2020/04/21)
A copper-catalyzed annulation of oxime acetates and α-amino acid ester derivatives for the easy preparation of 4-pyrrolin-2-ones bearing a 3-amino group has been developed. This process features the oxidation of amines with oxime esters as the internal oxidant to produce the active 1,3-dinucleophilic and 1,2-dielectrophilic species concurrently. The subsequent nucleophilic cyclization realizes the efficient construction of 4-pyrrolin-2-one derivatives.
CuCl2-catalyzed N[sbnd]O bond cleavage of oxime esters: Approach to imidazoheterocycles and furo[3,2-c]chromenyl fused imidazoles
Gudimella, Santosh K.,Kaur, Amanpreet,Kumar, Ram,Samanta, Sampak
supporting information, (2020/07/08)
An articulate approach to a diverse set of imidazoheterocycles in good to high yields via a copper-catalyzed aza-annulation of several oxime esters with a group of 2-amino-azaarenes was developed. The above cyclization reaction probably proceeds via a single electron transfer process which embodies a new technique for creating two new C[sbnd]N bonds for imidazole ring synthesis. Gratifyingly, the implementation of this chemistry could be further stretched to the synthesis of a novel class of fused imidazoles bearing a furo[3,2-c]chromene moiety via a sequential C[sbnd]N bond formation, followed by C(sp2)-H functionalization/5-endo-dig-oxacyclization (C[sbnd]C and C[sbnd]O bonds) of in situ produced fused imidazoles with cyclic enynones in the presence of copper(II) as a π-electrophilic Lewis acid catalyst.
Copper(0)/PPh3-Mediated Bisheteroannulations of o-Nitroalkynes with Methylketoximes Accessing Pyrazo-Fused Pseudoindoxyls
Meng, Huanxin,Xu, Zhenhua,Qu, Zhonghua,Huang, Huawen,Deng, Guo-Jun
supporting information, p. 6117 - 6121 (2020/08/12)
A copper(0)/PPh3-mediated cascade bisheteroannulation reaction of o-nitroalkynes with methylketoximes has been developed that provides viable access to a diverse range of pyrazo-fused pseudoindoxyl compounds. Synthetically useful functional groups including sensitive C-I bonds are compatible with this system. Mechanistic studies suggest a reaction cascade involving sequential PPh3-mediated deoxygenative cycloisomerization and copper-catalyzed [3 + 2] pyrazo-annulation.
Preparation method of pyrimidine salicylate oxime ester compound and application of compound as herbicide
-
Paragraph 0105; 0106, (2019/10/22)
The invention discloses a preparation method of a pyrimidine salicylate oxime ester compound and application of the compound as a herbicide, belongs to the technical field of herbicides, and relates to the application of the herbicide in selectively controlling gramineous weeds and broadleaf weeds for crops. The compound is a pyrithiobac oxime ester compound. The preparation method includes the following steps that acids of pyrithiobac are condensed with substituted acetophenoxime in the presence of an organic solvent and a condensation agent to prepare a (I) compound. At 45 g a.i./hm, thecompound can effectively control echinochloa crusgalli, eleusineindica, setaria viridis, amaranthus retroflexus, portulaca oleracea, chenopodium album and other grassy weeds and broadleaf weeds, can serve as a candidate herbicide in a cotton field and has potential industrial application. Meanwhile, the compound is environmentally friendly, low in toxicity and highly safe for crops such as cotton.The invention provides a preparation technology of the efficient and safe novel pyrimidine salicylate oxime ester compound with the herbicidal activity, the compound can be massively produced, the yield is high and the purity is high.
