- Stereospecific synthesis of 1,5-disubstituted tetrazoles from ketoximes via a Beckmann rearrangement facilitated by diphenyl phosphorazidate
-
A novel method for the stereospecific synthesis of 1,5-disubstituted tetrazoles from ketoximes via the Beckmann rearrangement was developed using diphenyl phosphorazidate (DPPA) as both the oxime activator and azide source. Various ketoximes were transformed into the corresponding 1,5-disubstituted tetrazoles with exclusive trans-group migration and no E-Z isomerization of the ketoxime. This method enables the preparation of 1,5-disubstituted tetrazoles without using toxic or explosive azidation reagents.
- Ishihara, Kotaro,Shioiri, Takayuki,Matsugi, Masato
-
supporting information
p. 1295 - 1298
(2019/04/13)
-
- SO2F2-Activated Efficient Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
-
A novel, mild and practical protocol for the efficient activation of the Beckmann rearrangement utilizing the readily available and economical sulfuryl fluoride (SO2F2 gas) has been developed. The substrate scope of the operationally simple methodology has been demonstrated by 37 examples with good to nearly quantitative isolated yields (over 90 % yield in most cases) in a short time, including B(OH)2, COOH, NH2, and OH substituted substrates. A tentative mechanism was proposed involving formation and elimination of key intermediate, sulfonyl ester.
- Zhang, Guofu,Zhao, Yiyong,Xuan, Lidi,Ding, Chengrong
-
supporting information
p. 4911 - 4915
(2019/07/31)
-
- The ruthenium-catalyzed C-H functionalization of enamides with isocyanates: Easy entry to pyrimidin-4-ones
-
Ruthenium-catalyzed heteroannulation between enamides and isocyanates has been realized as a complementary approach to conventional strategies for the synthesis of pyrimidin-4-ones. High step-A nd atom-economy was achieved for the rapid construction of such privileged scaffolds, which are found in a multitude of pharmaceutical compounds. The generality and practicability of this transformation were reflected by the broad scope of substrates with diverse functional groups, large-scale synthesis, and late-stage diversification.
- Shi, Pengfei,Li, Song,Hu, Lu-Min,Wang, Cong,Loh, Teck-Peng,Hu, Xu-Hong
-
supporting information
p. 11115 - 11118
(2019/09/20)
-
- A mild system for synthesis of aldoximes and ketoximes in the presence of N-hydroxyphthalimide in aqueous system
-
An efficient method for synthesis of oximes from aldehydes or ketones with N-hydroxyphthalimide or N-hydroxysuccinimide in water has been described. It is the first time to utilize NHPI as an oximation reagent to synthesize aldoximes and ketoximes from the corresponding organic carbonyl compounds without other reagents. The reaction tolerates various functional groups and affords the corresponding oximes in 76%–98% yields. The by-product phthalic acid can be recycled from the system. In addition, this method has been successfully applied to the synthesis of the precursor of some pharmacologically active amide molecules.
- Jiang, Xiaoying,Xu, Xiaohe,Lin, Yuyan,Yan, Yiyan,Li, Pingping,Bai, Renren,Xie, Yuanyuan
-
supporting information
p. 5879 - 5885
(2018/09/06)
-
- Beckmann rearrangement of ketoxime catalyzed by N-methyl-imidazolium hydrosulfate
-
Beckmann rearrangement of ketoxime catalyzed by acidic ionic liquid-N-methyl-imidazolium hydrosulfate was studied. Rearrangement of benzophenone oxime gave the desirable product with 45% yield at 90 ?C. When co-catalyst P2O5 was added, the yield could be improved to 91%. The catalyst could be reused three cycles with the same efficiency. Finally, reactions of other ketoximes were also investigated.
- Hu, Hongyu,Cai, Xuting,Xu, Zhuying,Yan, Xiaoyang,Zhao, Shengxian
-
-
- Copper-catalyzed synthesis of thiazol-2-yl ethers from oxime acetates and xanthates under redox-neutral conditions
-
A novel copper-catalyzed annulation of oxime acetates and xanthates for the synthesis of thiazol-2-yl ethers with remarkable regioselectivity has been developed. Various oxime acetates, whether derived from aryl ketones or alkyl ketones, or natural product cores are suitable for this conversion. Unique dihydrothiazoles were also obtained when both reaction sites were methine. Mechanistic studies indicated that imino copper(iii) intermediates were involved. In addition, this protocol proceeded under redox-neutral conditions and did not require additives or ligands.
- Zhu, Zhongzhi,Tang, Xiaodong,Cen, Jinghe,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
-
supporting information
p. 3767 - 3770
(2018/04/17)
-
- Catalytic Enantio- and Diastereoselective Mannich Addition of TosMIC to Ketimines
-
Chiral amines bearing a stereocenter in the α position are ubiquitous compounds with many applications in the pharmaceutical and agrochemical sectors, as well as in catalysis. Catalytic asymmetric Mannich additions represent a valuable method to access such compounds in enantioenriched form. This work reports the first enantio- and diastereoselective addition of commercially available p-toluenesulfonylmethyl isocyanide (TosMIC) to ketimines, affording 2-imidazolines bearing two contiguous stereocenters, one of which is fully-substituted, with high yields and excellent stereocontrol. The reaction, catalyzed by silver oxide and a dihydroquinine-derived N,P-ligand, is broad in scope, operationally simple, and scalable. Derivatization of the products provides enantioenriched vicinal diamines, precursors to NHC ligands and sp3-rich heterocyclic scaffolds. Computations are used to understand catalysis and rationalize stereoselectivity.
- Franchino, Allegra,Chapman, Jack,Funes-Ardoiz, Ignacio,Paton, Robert S.,Dixon, Darren J.
-
supporting information
p. 17660 - 17664
(2018/11/10)
-
- Catalyst free synthesis of mono- and disubstituted pyrimidines from O-acyl oximes
-
Transition-metal or iodine catalyzed transformations of O-acyl oximes to various N-heterocycles are well established. Herein, we report a catalyst free, oxime carboxylate based, three-component condensation method to access mono- and disubstituted pyrimidines. A broad range of substituted pyrimidines were prepared in moderate to excellent yields. Control experiments reveal that in situ generated formamidine is the key intermediate.
- Upare, Atul,Sathyanarayana, Pochampalli,Kore, Ranjith,Sharma, Komal,Bathula, Surendar Reddy
-
supporting information
p. 2430 - 2433
(2018/05/23)
-
- Divergent Iron-Catalyzed Coupling of O-Acyloximes with Silyl Enol Ethers
-
An iron-catalyzed coupling reaction of O-acyloximes and O-benzoyl amidoximes with silyl enol ethers is reported. The protocol provides access to functionalized pyrroles, 1,6-ketonitriles, pyrrolines and imidazolines via carbon-centered radicals generated from an initially formed iminyl radical. The intramolecular cyclization and ring-opening processes of the iminyl radical take place preferentially over reactions that proceed through a 1,3-hydrogen transfer, providing insights into iron-catalyzed reactions with oxime derivatives. The cheap and environmentally friendly iron catalyst, the broad substrate scope and the functional group compatibility make this protocol useful for synthesis of valuable nitrogen-containing products.
- Yang, Hai-Bin,Selander, Nicklas
-
supporting information
p. 1779 - 1783
(2017/02/15)
-
- Iron-Catalyzed Synthesis of 2H-Imidazoles from Oxime Acetates and Vinyl Azides under Redox-Neutral Conditions
-
A novel and versatile method for the synthesis of 2H-imidazoles via iron-catalyzed [3 + 2] annulation from readily available oxime acetates with vinyl azides has been developed. This denitrogenative process involved N-O/N-N bond cleavages and two C-N bond formations to furnish 2,4-substituted 2H-imidazoles. This protocol was performed under mild reaction conditions and needed no additives or ligands. Furthermore, this is a green reaction involving oxime acetate as internal oxidant, acetic acid, and nitrogen as byproducts.
- Zhu, Zhongzhi,Tang, Xiaodong,Li, Jianxiao,Li, Xianwei,Wu, Wanqing,Deng, Guohua,Jiang, Huanfeng
-
supporting information
p. 1370 - 1373
(2017/03/23)
-
- Synthesis of Air- and Moisture-Stable, Storable Chiral Oxorhenium Complexes and Their Application as Catalysts for the Enantioselective Imine Reduction
-
Air-/moisture-stable, crystalline, and storable chiral salicyloxazoline based oxorhenium(V) complexes have been synthesized and their catalytic application for the asymmetric reduction of ketimines using hydrosilane as hydride source is disclosed. A broad substrate scope, high yields, and excellent enantioselectivities (up to 99 %) are attained. Furthermore, the syntheses of enantiopure α-amino esters, γ- and δ-lactams, and isoindolinones have also been carried out using this methodology. Finally, the method has been applied to synthetic targets of pharmaceutical relevance, such as R-(+)-salsolidine and R-(+)-crispine A.
- Das, Braja Gopal,Nallagonda, Rajender,Dey, Dhananjay,Ghorai, Prasanta
-
supporting information
p. 12601 - 12605
(2015/09/01)
-
- One-pot oximation-Beckmann rearrangement of ketones and aldehydes to amides of industrial interest: Acetanilide, caprolactam and acetaminophen
-
High yielding one-pot oximation-Beckmann rearrangement of ketones to amides in ktrifluoroacetic acid has been conducted on several ketones and aldehydes. The substrate reactivity showed to depend on both oximation and Beckmann rearrangement reaction rate. In this synthetic procedure, trifluoroacetic acid acts as solvent, acid catalyst and organocatalyst and can be easily recycled.
- Aricò, Fabio,Quartarone, Giuseppe,Rancan, Elia,Ronchin, Lucio,Tundo, Pietro,Vavasori, Andrea
-
-
- Synthesis and antibacterial activity of oxime ester derivatives containing 16-isopropyl-5,9-dimethyl tetracyclo [10.2.2.01,10.04,9] hexadec-15-ene-5,14- dicarboxyl group
-
Acrylpimaric acid (16-isopropyl-5,9- dimethyltetracyclo [10. 2. 2. 0 1,10.04,9]hexadec- 15-ene-5,14-dicarboxylic acid) was prepared by rosin through Diels-Alder addition reaction, then a series of oxime ester derivatives containing acrylpimaryl (16-isopropyl-5,9-dimethyltetracyclo [10.2.2.01,10.04,9]hexadec-15-ene-5,14-dicarboxyl) group were synthesized. Their structures were characterized by IR, 1HNMR, MS, and elemental analysis. The antibacterial activity of these newly synthesized oxime ester derivatives against Gram-negative bacteria and Gram-positive bacteria were also investigated. The results indicate that compounds display extensive anti-bacterial activity against Gram-negative bacteria and Gram-positive bacteria. Especially compounds (4c, 4d, 4f, 4h and 4k) exhibit excellent anti-bacterial activity against Escherichia coli (Gram-negative bacteria). Compared with the diameter of inhibition zone is 9.66mm of the standard compound bromogeramine, which the diameter of inhibition zone is 12.17mm, 10.00mm, 10.33mm, 9.67mm and 9.67mm respectively.
- Li, Jian,Rao, Xiaoping,Shang, Shibin,Gao, Yanqing,Song, Binglei
-
experimental part
p. 217 - 222
(2012/04/23)
-
- O-TBS-N-tosylhydroxylamine: A reagent for facile conversion of alcohols to oximes
-
(Chemical Equation Presented) A variety of oximes were synthesized from the corresponding alcohols, alkyl halides, or alkyl sulfonates without using external oxidants. With this simple two-step procedure involving substitution with readily available TsNHOTBS and subsequent treatment with CsF, a range of oximes were prepared including the ones hardly preparable with conventional procedures.
- Kitahara, Katsushi,Toma, Tatsuya,Shimokawa, Jun,Fukuyama, Tohru
-
supporting information; experimental part
p. 2259 - 2261
(2009/05/26)
-
- Silicon-catalyzed conversion of nitro compounds into ketones and poly(1,3-diketones)
-
The reaction of various secondary nitro compounds with 1.1 equivalents of potassium hydride in 1,4-dioxane and then with 0.10 equivalent of chlorotrimethylsilane gave the corresponding ketones in 62-90% yields. By a similar strategy, poly(1,3-diketones) were synthesized directly from nitroalkenes with sodium ethoxide, potassium hydride, and chlorotrimethylsilane in 1,4-dioxane. The use of chlorotrimethylsilane in a catalytic amount was the key to the success of this transformation; the use of an excess of chlorotrimethylsilane led to poor yields for the same reactions. Georg Thieme Verlag Stuttgart.
- Hwu, Jih Ru,Josephrajan, Thainashmuthu,Tsay, Shwu-Chen
-
p. 3305 - 3308
(2008/09/17)
-
- Synthesis of Quinolines and 2H-Dihydropyrroles by Nucleophilic Substitution at the Nitrogen Atom of Oxime Derivatives
-
Isomerization of oxime derivatives was researched in detail to find out the methods for the syn-anti isomerization of O-substituted oximes. Based on these findings were developed simple methods for the preparation of aza-heterocycles from both stereoisomers of oximes. Quinolines were synthesized from β-aryl ketone oximes by treatment with trifluoroacetic anhydride and 4-chloranil. γ,δ-Unsaturated O-methoxyacetyloximes were transformed to 2H-dihydropyrroles by reaction with methoxy-acetic acid.
- Kitamura, Mitsuru,Yoshida, Masayuki,Kikuchi, Takashi,Narasaka, Koichi
-
p. 2415 - 2426
(2007/10/03)
-
- Mono-deoxygenation of nitroalkanes, nitrones, and heterocyclic N-oxides by hexamethyldisilane through 1,2-elimination: Concept of 'counterattack reagent'
-
Transformation of secondary nitroalkanes to ketoximes was achieved in 40-73% yields by treatment of the corresponding nitronate anions with hexamethyldisilane. In this new mono-deoxygenation process, hexamethyldisilane acted as a 'counterattack reagent'. The conversion of nitrones to imines was also achieved in 82-88% yields by use of trimethylsilyllithium. Similarly, heterocyclic N-oxides were converted to the corresponding N-heterocycles in 73-86% yields. These deoxygenation processes presumably involve a 1,2-elimination.
- Hwu, Jih Ru,Tseng, Wen Nan,Patel, Himatkumar V.,Wong, Fong Fuh,Horng, Den-Nan,Liaw, Ben Ruey,Lung Ching, Lin
-
p. 2211 - 2218
(2007/10/03)
-
- COUNTERATTACK REAGENTS: THIOSILANES IN THE CONVERSION OF NITRO COMPOUNDS TO THIOHYDROXAMIC ACIDS AND THIOHYDROXIMATES
-
Various primary nitro compounds were reacted sequentially with KH and Me3SiSSiMe3 in THF to give thiohydroxamic acids in 56-92 percent yields.By the same strategy, a thiohydroxamic acid was obtained in 50 percent yield by treatment of trans-β-nitrostyrene with i-PrSLi in THF and then with Me3SiSSiMe3.Reaction of primary nitro compounds with n-BuLi and then with MeSSiMe3 or PhSSiMe3 produced the corresponding thiohydroximates in 61-78 percent yields.Secondary nitro compounds were converted to oximes in 68-96 percent yields by reaction with KH and Me3SiSSiMe3 or MeSSiMe3 in THF or 1,4-dioxane.In these "one-flask" reactions, thiosilanes Me3SiSSiMe3, MeSSiMe3, and PhSSiMe3 acted as "counterattack reagents".
- Hwu, Jih Ru,Tsay, Shwu-Chen
-
p. 7413 - 7428
(2007/10/02)
-
- NEW ASPECTS IN THE HYDROGENOLYTIC OPENING OF 2-ISOXAZOLINES
-
It has been observed that the hydrogenolytic opening of 2-isoxazolines depends on the substituents present in positions 3 and 5.The hydrogenolysis on 10percent Pd/C of 2-isoxazolines, substituted in position 3 with carbonyl or carboxyl groups and in posit
- Auricchio, Sergio,Ricca, Aldo
-
p. 3983 - 3986
(2007/10/02)
-