- Cross-Linked Surface Engineering to Improve Iron Porphyrin Catalytic Activity
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Quasi-two-dimensional (QTD) structural heterogeneous catalysts have attracted a broad interest in multidisciplinary research due to their unique structure, preeminent surface properties and outstanding catalytic performance. Herein, a HZIF@TCPP-Fe/Fe hete
- Zhang, Dongxu,Liu, Jia,Du, Peiyao,Zhang, Zhen,Ning, Xingming,Deng, Yang,Yin, Dan,Chen, Jing,Han, Zhengang,Lu, Xiaoquan
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- Hydrogen peroxide based oxidation of hydrazines using HBr catalyst
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Azo compounds (RN = NR′) are an important class of organic molecules that find wide application in organic synthesis. Herein, we report an efficient, practical and metal-free oxidation of hydrazines (RNH-NHR’) to azo compounds using 5 mol% HBr and hydrogen peroxide as terminal oxidant. This new method has been demonstrated by 40 examples with excellent yields. In addition, we showcased two examples of the one-pot sequential reactions involving our hydrazine oxidation/hydrolysis/Heck reaction or Cu-catalyzed N-arylation with aryl boronic acid. The distinct advantages of this protocol include metal-free catalysis, waste prevention, and easy operation.
- Du, Wanting,Ma, Zichao,Shao, Liming,Wang, Jian
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- Encapsulation of Porphyrin-Fe/Cu Complexes into Coordination Space for Enhanced Selective Oxidative Dehydrogenation of Aromatic Hydrazides
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The encapsulation of specific nanoentities into hollow nanomaterials derived from metal organic frameworks has attracted continuous and growing research attentions owing to their unique structural properties and unusual synergistic functions. Herein, usin
- Zhang, Dongxu,Du, Peiyao,Liu, Jia,Zhang, Ruizhong,Zhang, Zhen,Han, Zhengang,Chen, Jing,Lu, Xiaoquan
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- Aerobic Oxidation of Alkyl 2-Phenylhydrazinecarboxylates Catalyzed by CuCl and DMAP
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Recently, various fruitful organic reactions such as a catalytic Mitsunobu reaction were reported by virtue of alkyl 2-phenylazocarboxylates, however, the synthesis of alkyl 2-phenylazocarboxylates largely depended on the stoichiometric use of toxic oxidants. In this manuscript, an environment-friendly aerobic oxidative transformation of alkyl 2-phenylhydrazinecarboxylates to alkyl 2-phenylazocarboxylates is disclosed. The use of CuCl and DMAP system efficiently catalyzed the aerobic oxidation of alkyl 2-phenylhydrazinecarboxylates under mild conditions. The reaction rate of the present Cu-catalysis was much faster than that of the previously reported Fe-catalysis, and a variety of azo products were synthesized within 3 h. The present protocol was effective on larger scale. It was observed that the produced azo compound could undergo various reactions without isolation through one-pot sequential protocols.
- Kim, Min Hye,Kim, Jinho
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p. 1673 - 1679
(2018/02/09)
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- Oxidation Potential Tunable Organic Molecules and Their Catalytic Application to Aerobic Dehydrogenation of Tetrahydroquinolines
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In this work, oxidation potential tunable organic molecules, alkyl 2-phenyl hydrazocarboxylates, were disclosed. The exquisite tuning of their oxidation potentials facilitated a catalytic dehydrogenation of 1,2,3,4-tetrahydroquinolines in the presence of Mn(Pc) and O2.
- Jung, Dahyeon,Jang, Seol Heui,Yim, Taeeun,Kim, Jinho
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supporting information
p. 6436 - 6439
(2018/10/15)
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- Cp?Rh(III)-catalyzed electrophilic amination of arylboronic acids with azo compounds for synthesis of arylhydrazides
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A [Cp?Rh(iii)]-catalyzed electrophilic amination of arylboronic acids with diethyl azodicarboxylate (DEAD) was developed, and arylhydrazides were produced in excellent yields and selectivity. The analogous amination with the arylazocarboxylates afforded t
- Lau, Yan-Fung,Chan, Chun-Ming,Zhou, Zhongyuan,Yu, Wing-Yiu
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p. 6821 - 6825
(2016/07/21)
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- Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents
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Ethyl 2-arylhydrazinecarboxylates can work as organocatalysts for Mitsunobu reactions because they provide ethyl 2-arylazocarboxylates through aerobic oxidation with a catalytic amount of iron phthalocyanine. First, ethyl 2-(3,4-dichlorophenyl)hydrazinecarboxylate has been identified as a potent catalyst, and the reactivity of the catalytic Mitsunobu reaction was improved through strict optimization of the reaction conditions. Investigation of the catalytic properties of ethyl 2-arylhydrazinecarboxylates and the corresponding azo forms led us to the discovery of a new catalyst, ethyl 2-(4-cyanophenyl)hydrazinecarboxylates, which expanded the scope of substrates. The mechanistic study of the Mitsunobu reaction with these new reagents strongly suggested the formation of betaine intermediates as in typical Mitsunobu reactions. The use of atmospheric oxygen as a sacrificial oxidative agent along with the iron catalyst is convenient and safe from the viewpoint of green chemistry. In addition, thermal analysis of the developed Mitsunobu reagents supports sufficient thermal stability compared with typical azo reagents such as diethyl azodicarboxylate (DEAD). The catalytic system realizes a substantial improvement of the Mitsunobu reaction and will be applicable to practical synthesis.
- Hirose, Daisuke,Gazvoda, Martin,Ko?mrlj, Janez,Taniguchi, Tsuyoshi
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p. 5148 - 5159
(2016/07/29)
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- Azocarbonyl-functionalized silanes
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The invention provides azocarbonyl-functionalized silanes of the general formula I (R1)3-a(R2)aSi-RI-NH-C(O)-N=N-R4. They are prepared by a procedure in which in a first step hydrazine of t
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- Catalytic Aerobic Oxidation of Arylhydrazides with Iron Phthalocyanine
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A convenient method for the synthesis of 2-arylazocarboxylates from 2-arylhydrazinecarboxylates by aerobic oxidation with iron phthalocyanine is described. The reaction is applicable to oxidative activation of 1-acyl-2-phenylhydrazines. Some preliminary experiments suggest Michaelis-Menten kinetics and participation of radical species in the reaction mechanism.
- Hashimoto, Takuma,Hirose, Daisuke,Taniguchi, Tsuyoshi
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supporting information
p. 3346 - 3352
(2015/11/03)
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- Recyclable mitsunobu reagents: Catalytic mitsunobu reactions with an iron catalyst and atmospheric oxygen
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Aerobic recycling: A catalytic amount of a hydrazine reagent is sufficient to promote Mitsunobu reactions in the presence of triphenylphosphine, an iron catalyst, and air. The active form of the catalyst, an azo species, can be readily generated by iron-c
- Hirose, Daisuke,Taniguchi, Tsuyoshi,Ishibashi, Hiroyuki
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supporting information
p. 4613 - 4617
(2013/06/04)
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- N-(Propargyl)diazenecarboxamides for 'click' conjugation and their 1,3-dipolar cycloadditions with azidoalkylamines in the presence of Cu(II)
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Propargyl functionalized diazenes 1 were prepared by two different approaches and were examined as alkyne click components in copper-catalyzed azide-alkyne cycloadditions (CuAAC) with 2-(azidomethyl)pyridine 5a and four α-azido-ω-aminoalkanes C2-C5 (5b-e)
- Urankar, Damijana,Steinbücher, Miha,Kosjek, Jaka,Ko?mrlj, Janez
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experimental part
p. 2602 - 2613
(2010/05/01)
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- Toward enediyne mimics: Methanolysis of azoesters and a bisazoester
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Enediyne anticancer antibiotics have attracted tremendous interest in the past decade. The inherent difficulty in synthesizing these structurally complex natural products with the strained enediyne moiety has motivated a search for simpler molecules that mimic enediyne chemistry. The ultimate objective is to identify molecules that produce 1,4-benzenoid diradicals, which are known to induce DNA cleavage in the natural products. Toward this goal, several aromatic azoesters have been synthesized, and EPR reveals the presence of radical intermediates in their methanolysis. A 1,4-bisazoester has also been synthesized, and its methanolysis products have been studied by reversed-phase HPLC. The formation of 1,2-dicyanobenzene from the 1,4- bisazoester is consistent with the existence of a 1,4-diradical intermediate.
- Srinivasan, Veeraraghavan,Jebaratnam, David J.,Budil, David E.
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p. 5644 - 5649
(2007/10/03)
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- 1,3,4-OXADIAZINE DERIVATIVES FROM CYCLOHEXANONE ENAMINES AND ASYMMETRIC DIIMIDES; POSSIBILITY OF RING-CHAIN TAUTOMERISM IN SUCH HETEROCYCLIC SYSTEM
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1,3,4-oxadiazine derivatives, in equilibrium with their corresponding trisubstituted enamine isomers, are obtained in a regiospecific way from cyclohexanone enamines and ethoxycarbonyl aroyl diimides.Such an equilibrium is not present in analogous oxadiazine systems, derived from aryl aroyl diimides.
- Forchiassin, M.,Risaliti, A.,Russo, C.
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p. 2921 - 2928
(2007/10/02)
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