2369-20-2Relevant academic research and scientific papers
Redox-Neutral Selenium-Catalysed Isomerisation of para-Hydroxamic Acids into para-Aminophenols
Chuang, Hsiang-Yu,Schupp, Manuel,Meyrelles, Ricardo,Maryasin, Boris,Maulide, Nuno
supporting information, p. 13778 - 13782 (2021/03/31)
A selenium-catalysed para-hydroxylation of N-aryl-hydroxamic acids is reported. Mechanistically, the reaction comprises an N?O bond cleavage and consecutive selenium-induced [2,3]-rearrangement to deliver para-hydroxyaniline derivatives. The mechanism is studied through both 18O-crossover experiments as well as quantum chemical calculations. This redox-neutral transformation provides an unconventional synthetic approach to para-aminophenols.
Practical bromination of arylhydroxylamines with SOBr2 towards ortho-bromo-anilides
Du, Yuanbo,Feng, Lei,Gao, Hongyin,Guo, Lirong,Lu, Haifeng,Xi, Zhenguo
supporting information, (2021/05/19)
A facile approach for synthesizing ortho-bromoanilides from readily available aryhydroxylamines and thionyl bromide is demonstrated in this work. Mild reaction conditions and broad scope of substrates ranging from heterocyclic structures to pharmaceutics-potential motifs are used in the reactions of this paper. Efficient bromination of ortho C–H bonds of the aryhydroxylamines has been achieved. Ortho-bromoanilide products were obtained in good to excellent yields, and model scaled-up reactions of this synthetic approach are shown in this work.
Regioselective installation of fluorosulfate (-OSO2F) functionality into aromatic C(sp2)-H bonds for the construction of: Para-amino-arylfluorosulfates
Fang, Wan-Yin,Zha, Gao-Feng,Zhao, Chuang,Qin, Hua-Li
supporting information, p. 6273 - 6276 (2019/06/07)
The construction of para-amino-arylfluorosulfates was achieved through installation of fluorosulfate (-OSO2F) functionality into aromatic C(sp2)-H bonds by the reaction of N-arylhydroxylamine with sulfuryl fluoride (SO2Fs
Hydroxamic Acids as Chemoselective (ortho-Amino)arylation Reagents via Sigmatropic Rearrangement
Shaaban, Saad,Tona, Veronica,Peng, Bo,Maulide, Nuno
supporting information, p. 10938 - 10941 (2017/08/30)
The use of readily available hydroxamic acids as reagents for the chemoselective (ortho-amino)arylation of amides is described. This reaction proceeds under metal-free, mild conditions, displays a very broad scope, and constitutes a direct approach for the metal-free attachment of aniline residues to carbonyl derivatives.
TRIFLUOROMETHOXYLATION OF ARENES VIA INTRAMOLECULAR TRIFLUOROMETHOXY GROUP MIGRATION
-
Page/Page column 60-61, (2016/05/02)
The present invention provides a process of producing a trifluoromethoxylated aryl or trifluoromethoxylated heteroaryl having the structure: (I), wherein A is an aryl or heteroaryl, each with or without subsutitution; and R1 is -H, -(alkyl), -(alkenyl), -(alkynyl), -(aryl), -(heteroaryl), - (alkylaryl), - (alkylheteroaryl), -NH-(alkyl), -N(alkyl)2, -NH-(alkenyl), -NH-(alkynyl) -NH-(aryl), -NH-(heteroaryl), -O-(alkyl), -O-(alkenyl), -O-(alkynyl), -O-(aryl), -O-(heteroaryl), -S-(alkyl), -S- (alkenyl), -S-(alkynyl), -S-(aryl), or -S-(heteroaryl), comprising: (a) reacting a compound having the structure: (II), with a trifluoromethylating agent in the presence of a base in a first suitable solvent under conditions to produce a compound having the structure: (III); and (b) maintaining the compound produced in step (a) in a second suitable solvent under conditions sufficient to produce the trifluoromethoxylated aryl or trifluormethoxylated heteroaryl having the structure: (I).
Mechanistic studies on intramolecular C-H trifluoromethoxylation of (hetero)arenes via OCF3-migration
Lee, Katarzyna N.,Lei, Zhen,Morales-Rivera, Cristian A.,Liu, Peng,Ngai, Ming-Yu
supporting information, p. 5599 - 5605 (2016/07/06)
The one-pot two-step intramolecular aryl and heteroaryl C-H trifluoromethoxylation recently reported by our group has provided a general, scalable, and operationally simple approach to access a wide range of unprecedented and valuable OCF3-containing building blocks. Herein we describe our investigations to elucidate its reaction mechanism. Experimental data indicate that the O-trifluoromethylation of N-(hetero)aryl-N-hydroxylamine derivatives is a radical process, whereas the OCF3-migration step proceeds via a heterolytic cleavage of the N-OCF3 bond followed by rapid recombination of a short-lived ion pair. Computational studies further support the proposed ion pair reaction pathway for the OCF3-migration process. We hope that the current study would provide useful insights for the development of new transformations using versatile N-(hetero)aryl-N-hydroxylamine synthons.
Influence of the side-group at C=N bridging bond of bis-aryl Schiff bases on the wavelength of absorption maximum of ultraviolet absorption spectra
Luo, Qingqing,Cao, Chao-Tun,Cao, Zhongzhong,Cao, Chenzhong
, p. 406 - 413 (2016/07/28)
The compounds N-(benzylidene)-anilines XArCH=NArY (XBAY), N-(phenyl-ethylene)-anilines XArC(CH3)=NArY (XPEAY) and N-phenyl-α-phenylnitrones XArCH=N(O)ArY (XPNY) have bridging group CH=N, C(CH3)=N and CH=N(O) respectively, in which the C(CH3)=N has a side-group methyl CH3 at carbon end and the CH=N(O) has a side-group O atom at nitrogen end. In this work, a series of XPEAY and XPNY were synthesized, and their longest wavelength maximum λmax (nm) of ultraviolet absorption spectra were measured. Then the change regularity of the νmax (cm-1, νmax=1/λmax) of XPEAY and XPNY were investigated, and they were compared with that of XBAY (reported by ref.26). The results indicate: (1) There are no good linear relationships between the νmax of XBAYs and XPEAYs or XPNYs. (2) In case of a same set of X-Y group couples, the distribution of λmax of XPEAYs is larger than that of XPNYs. (3) The side-group CH3 makes the effect of σ(X) larger than that of σ(Y) on the νmax of XPEAYs, whereas the O atom makes the effect of σ(Y) larger than that of σ(X) on the νmax of XPNYs. (4) The cross-interaction between X and Y has important effect on the all νmax. However, the cross-interaction between CH3 and X/Y has not important effect on the νmax of XPEAY, and the cross-interaction between O and X/Y has not important effect on the νmax of XPNY. Copyright
Trifluoromethoxylation of arenes: Synthesis of ortho- Trifluoromethoxylated aniline derivatives by OCF3 migration
Hojczyk, Katarzyna N.,Feng, Pengju,Zhan, Chengbo,Ngai, Ming-Yu
supporting information, p. 14559 - 14563 (2015/01/09)
Aryl trifluoromethoxylation by a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxylamine derivatives and intramolecular OCF3 migration is presented. This protocol allows easy access to a wide range of synthetically useful ortho-OCF3 aniline derivatives. In addition, it utilizes bench-stable reagents, is operationally simple, shows high functional-group tolerance, and is amenable to gram-scale as well as one-pot synthesis.Areaction mechanism of a heterolytic cleavage of the N-OCF3 bond followed by recombination of the resulting nitrenium ion and trifluoromethoxide is proposed for the OCF3-migration reaction.
