- 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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- Ultrasound promoted environmentally benign, highly efficient, and chemoselective N-tert-butyloxycarbonylation of amines by reusable sulfated polyborate
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The sulfated polyborate catalyzed an efficient and chemoselective N-tert-butyloxycarbonylation of amines under ultrasonic irradiation is developed. A broad substrate scope has been demonstrated for N-Boc protection of various primary/secondary amines. It allows converting several aliphatic/aryl/heteroaryl amines, amino alcohol, aminoester, and chiral amines to their N-Boc-protected derivatives under solvent-free conditions with excellent yields. The protocol has several advantages such as easy catalyst, and product isolation, short reaction time, excellent yields, outstanding chemoselectivity, and catalyst recyclability, among others. This makes the process practicable, economical, and environmentally benign.
- Pise, Ashok S.,Ingale, Ajit P.,Dalvi, Navnath R.
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supporting information
p. 3768 - 3780
(2021/10/26)
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- Sulfated tungstate: A highly efficient, recyclable and ecofriendly catalyst for chemoselective N-tert butyloxycarbonylation of amines under the solvent-free conditions
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Sulfated tungstate catalyzed an efficient and ecofriendly protocol has been described for the chemoselective N-tert-butyloxycarbonylation of amines under the solvent-free conditions at room temperature. The variety of functionalized aliphatic, aromatic and heteroaromatic amines efficiently undergoes the N-tert-butyloxycarbonylation under the developed protocol. The aminoalcohol, aminophenol, aminoester as well as various chiral amines underwent the chemoselective N-Boc protection under the optimized reaction condition. The rapid reaction rate, mild conditions, very good functional group tolerance, excellent yield, solvent-free, easy recovery products and excellent catalyst recyclability are the advantages of this protocol. This makes the protocol feasible, economical and environmentally benign.
- Ingale, Ajit P.,Shinde, Sandeep V.,Thorat, Nitin M.
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supporting information
p. 2528 - 2543
(2021/07/02)
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- Nanoceria as an efficient and green catalyst for the chemoselective N-tert-butyloxycarbonylation of amines under the solvent-free conditions
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Nanocerium oxide mediated an efficient and green protocol has been described for the chemoselective N-tert-butyloxycarbonylation of amines under the solvent-free conditions at ambient temperature. Various aliphatic, aromatic and heteroaromatic amines were protected using developed protocol and several functional groups such as alcohol, phenol and ester were well tolerated under these conditions. The rapid reaction rate, mild conditions, very good functional group tolerance, excellent yield, solvent-free, easy recovery products and excellent catalyst recyclability are the advantages of this protocol. This makes the protocol feasible, economical and environmentally benign.
- Garad, Dnyaneshwar N.,Ingale, Ajit P.,Shinde, Sandeep V.,Ukale, Dattatraya
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supporting information
p. 1656 - 1668
(2021/04/05)
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- One-Pot Synthesis of Indoles and Pyrazoles via Pd-Catalyzed Couplings/Cyclizations Enabled by Aqueous Micellar Catalysis
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An effective one-pot synthesis of either indoles or pyrazoles can be achieved via Pd-catalyzed aminations followed by subsequent cyclizations facilitated by aqueous micellar catalysis. This new technology includes efficient couplings with low loadings of palladium, a more stable source of the required hydrazine moiety, greater atom economy for the initial coupling, and reduced reaction temperatures, all leading to environmentally responsible processes.
- Akporji, Nnamdi,Braga, Felipe C.,Gabriel, Christopher M.,Landstrom, Evan B.,Lee, Nicholas R.,Lipshutz, Bruce H.
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supporting information
(2020/09/02)
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- ACLY INHIBITORS AND USES THEREOF
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The present invention provides compounds useful as inhibitors of ATP citrate lyase (ACLY), compositions thereof, and methods of using the same.
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Paragraph 00836
(2020/06/01)
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- Electrochemical dehydrogenation of hydrazines to azo compounds
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A strategy for the electrochemical dehydrogenation of hydrazine compounds is disclosed under ambient conditions. This protocol proceeded smoothly in ethanol by employing electrons as clean oxidants. Its synthetic value is well demonstrated by the highly efficient synthesis of symmetric and unsymmetric azo compounds. It is an environmentally friendly transformation and the present protocol was effective on a large scale.
- Du, Ke-Si,Huang, Jing-Mei
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supporting information
p. 1680 - 1685
(2019/04/08)
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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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- Synthesis of Hydrazines via Radical Generation and Addition of Azocarboxylic tert -Butyl Esters
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A new chemistry of azo compounds that is a radical generation and addition in situ of azocarboxylic tert-butyl esters to synthesize hydrazines has been described. The protocol provides a novel strategy for the synthesis of various hydrazines. The advantag
- Ru, Chen-Hao,Guo, Shi-Huan,Pan, Gao-Fei,Zhu, Xue-Qing,Gao, Ya-Ru,Wang, Yong-Qiang
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supporting information
p. 1910 - 1913
(2018/04/16)
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- Palladium/copper-catalyzed arylation of alkenes with N′-acyl arylhydrazines
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A novel ligand-free palladium/copper-catalyzed Heck-type coupling reaction of alkenes and N′-acyl arylhydrazines has been developed by using air as the terminal oxidant. This protocol features wide functional group tolerance and produces highly chemoselective and regioselective products with good to excellent yields.
- Zhang, Ji-Quan,Cao, Jun,Li, Wei,Li, Shu-Min,Li, Yong-Kang,Wang, Jian-Ta,Tang, Lei
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supporting information
p. 437 - 441
(2017/02/05)
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- Diaza [1,4] Wittig-type rearrangement of N-allylic-N-Boc-hydrazines into γ-amino- N -Boc-enamines
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Diaza [1,4] Wittig-type rearrangement of N-allylic-N-Boc-hydrazines into γ-amino-N-Boc-enamines was demonstrated. The scope and limitation, experimental mechanistic studies, and a proposed reaction mechanism were also described.
- Tayama, Eiji,Kobayashi, Yoshiaki,Toma, Yuka
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supporting information
p. 10570 - 10573
(2016/09/02)
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- Copper(I)-Catalyzed Synthesis of Chlorinated Tetrahydropyridazin-3-ones and 1,2-Diazepan-3-ones from N-Allyl-N′-trichloroacetylhydrazines
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The synthesis of chlorinated tetrahydropyridazin-3-ones and 1,2-diazepan-3-ones has been developed. The present paper describes the application of Cu(I)-catalyzed ATRC for the synthesis of heterocyclic molecules containing two heteroatoms (i.e., nitrogen)
- Ram, Ram N.,Soni, Vineet Kumar
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supporting information
p. 276 - 282
(2016/02/14)
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- Tuning the Annulation Reactivity of Vinyl Azides and Carbazates: A Divergent Synthesis of Aza-pyrimidinones and Imidazoles
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A divergent cascade annulation has been developed using readily available vinyl azides and carbazates with a wide range of substituents. Vinyl azides were successfully applied as bifunctional partners to prepare aza-pyrimidinones via 6-ring closure with c
- Shao, Jiaan,Liu, Xingyu,Shu, Ke,Tang, Pai,Luo, Jing,Chen, Wenteng,Yu, Yongping
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supporting information
p. 4502 - 4505
(2015/09/28)
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- Ene-hydrazide from enol triflate for the regioselective Fischer indole synthesis
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Ene-hydrazide prepared from enol triflate undergoes a Fischer indolization reaction to give the corresponding indole with complete regioselectivity. The starting enol triflate is readily accessed in regiochemically defined form from the ketone precursor via various well-established methods. This new protocol was successfully applied to the synthesis of desbromoarborescidine A, a natural β-carboline alkaloid, difficult to prepare with conventional Fischer indole synthesis.
- Lim, Byeong-Yun,Jung, Bo-Eun,Cho, Cheon-Gyu
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supporting information
p. 4492 - 4495
(2015/01/09)
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- A mild and green method for the N-BOC protection of amines without assistant of catalyst under solvent-free conditions
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A facile, green and versatile method for the Boc protection of amines has been developed by a treatment with (Boc)2O without any additive at room temperature. The method is general for the preparation of N-Boc derivatives of aliphatic (acyclic and cyclic), aromatic, and heteroaromatic amines; primary and secondary amines. The advantages of this method are green, simplicity, short reaction times and excellent yields.
- Mojtahedi, Mohammad Majid,Niknejad, Nina,Veisi, Hojat
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p. 121 - 125
(2013/07/26)
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- Syntheses and antitumor activities of N′1, N′3-dialkyl-N′1,N′3-di- (alkylcarbonothioyl) malonohydrazide: The discovery of elesclomol
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A series of N′1,N′3-dialkyl- N′1,N′3-di(alkylcarbonothioyl) malonohydrazides have been designed and synthesized as anticancer agents by targeting oxidative stress and Hsp70 induction. Structure-activity relationship (SAR) studies lead to the discovery of STA-4783 (elesclomol), a novel small molecule that has been evaluated in a number of clinical trials as an anticancer agent in combination with Taxol.
- Chen, Shoujun,Sun, Lijun,Koya, Keizo,Tatsuta, Noriaki,Xia, Zhiqiang,Korbut, Timothy,Du, Zhenjian,Wu, Jim,Liang, Guiqing,Jiang, Jun,Ono, Mitsunori,Zhou, Dan,Sonderfan, Andrew
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p. 5070 - 5076
(2013/09/12)
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- Microwave assisted mild, rapid, solvent-less, and catalyst-free chemoselective N-tert-butyloxycarbonylation of amines
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Microwave assisted simple, rapid, solventless, and catalyst-free chemoselective method for the protection of amino group in aromatic, aliphatic, heterocyclic, aralkyl amines, phenyl hydrazine, and amino acid esters in good to excellent isolated yield (83-98%) in short reaction time (2-12 min) has been reported.
- Dighe, Satish N.,Jadhav, Hemant R.
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p. 5803 - 5806
(2012/10/29)
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- Combinatorial aid for underprivileged scaffolds: Solution and solid-phase strategies for a rapid and efficient access to novel aza-diketopiperazines (aza-DKP)
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An efficient solution-phase synthesis of aza-diketopiperazines (aza-DKP, triazinediones) is reported. A structurally diverse collection of c-[aza-alkylGly-Pro] derivatives and yet unreported 2,4,5-trisubstituted-1,2,4- triazine-3,6-diones has been synthesized starting from Fmoc-l-Pro-OH and various Fmoc-l-amino acids. To extend the practical value of this class of dipeptidomimetics, a general solid-phase synthesis approach amenable to library production was developed on both Wang-PS and HMBA-PS resins. The final acidic treatment of the resins in TFA/water mixture at room temperature enabled the rapid and quantitative cyclization/release highly pure triazinediones. The conformational preferences and the spatial organization of the three substituents of a representative 2,4,5-trisubstituted-1,2,4-triazine-3,6-dione were investigated by X-ray diffraction and 1H NMR spectroscopy.
- Bonnet, Dominique,Margathe, Jean-Francois,Radford, Sally,Pflimlin, Elsa,Riche, Stephanie,Doman, Pete,Hibert, Marcel,Ganesan
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experimental part
p. 323 - 334
(2012/07/13)
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- Thioglycoluril as a highly efficient, recyclable and novel organocatalyst for N-Boc protection of amines
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A simple and efficient protocol for the chemoselective mono-N-Boc protection of various structurally diverse amines with di-tert-butyl dicarbonate using thioglycoluril as the catalyst is described. The catalyst can be readily separated from the reaction products by simple filtration and recovered for reuse. No competitive side reactions, such as formation of isocyanate, urea, oxazolidinone, and N,N-di-Boc derivatives were observed.
- Khaksar, Samad,Vahdat, Seyed Mohammad,Tajbakhsh, Mahmood,Jahani, Fatemeh,Heydari, Akbar
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experimental part
p. 6388 - 6391
(2011/01/03)
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- Amberlyst-15: a mild, efficient and reusable heterogeneous catalyst for N-tert-butoxycarbonylation of amines
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A mild and versatile method has been developed for the chemoselective N-tert-butoxycarbonylation of amines in the presence of Amberlyst-15 under solvent-free condition. The method is general for the preparation of N-Boc derivatives of aliphatic (acyclic and cyclic) and aromatic amines.
- Kumar, K. Shiva,Iqbal, Javed,Pal, Manojit
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experimental part
p. 6244 - 6246
(2010/01/11)
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- Effective strategy for the systematic synthesis of hydrazine derivatives
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A new and efficient strategy for the systematic synthesis of hydrazine derivatives is reported. It allows the synthesis of up to tetrasubstituted hydrazine derivatives with minimal number of steps using only one protecting group or without any of them at all. Simple and readily available starting materials such as hydrazine hydrate or phenylhydrazine can be used. A variety of substrates were used to investigate scope and limitations of this strategy, additionally one full synthetic sequence was performed.
- Bredihhin, Aleksei,M?eorg, Uno
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p. 6788 - 6793
(2008/12/20)
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- A selective method for cleavage of N-Troc-protected hydrazines and amines under mild conditions using mischmetal and TMSCI
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The Troc (2,2,2-trichloroethoxycarbonyl) protecting group was efficiently removed under neutral conditions from corresponding protected hydrazines and amines using mischmetal in good to excellent yields. Two new substituted hydrazines were synthesised.
- Vellemaee, Eerold,Lebedev, Oleg,Sillard, Rannar,Maeeorg, Uno
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p. 685 - 687
(2007/10/03)
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- Addition of arylboronic acids to symmetrical and unsymmetrical azo compounds
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(Chemical Equation Presented) The addition of aryl- and heteroarylboronic acids to azo compounds is described. Copper salt catalysis was necessary to perform the reaction under mild conditions and high yields. Excellent regioselectivity was observed in addition to unsymmetrical azo compounds.
- Kisseljova, Ksenija,Tsubrik, Olga,Sillard, Rannar,Maeeorg, Sirje,Maeeorg, Uno
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- Oxaziridine-mediated amination of primary amines: Scope and application to a one-pot pyrazole synthesis
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(Chemical Equation Presented) Electrophilic amination of primary aliphatic and aromatic amines is reported using a diethylketomalonate-derived oxaziridine to afford the corresponding N-Boc hydrazines in good to excellent yields. The method allows a one-pot synthesis of pyrazoles from primary amines.
- Armstrong, Alan,Jones, Lyn H.,Knight, Jamie D.,Kelsey, Richard D.
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p. 713 - 716
(2007/10/03)
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- HIV protease inhibitors: Synthesis and activity of N-aryl-N′- hydroxyalkyl hydrazide pseudopeptides
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We describe the synthesis and activities of a series of pseudopeptides containing an N-aryl-N′-hydroxyalkyl hydrazide core structure to inhibit human immunodeficiency virus protease and viral replication. Of the series, compound Hmb-Leu-N(Bzl)-N(CH2-CH-OH)-rPro-Boc (24) displayed the greatest inhibitory potency (IC50 1 μM) and exhibited enzymatic resistance and stability in vitro.
- Marastoni,Baldisserotto,Trapella,McDonald,Bortolotti,Tomatis
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p. 445 - 451
(2007/10/03)
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- Synthesis of hydrazines with aromatic substituents using triarylbismuth reagents
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Smooth monoarylation of two triprotected hydrazine reagents under mild conditions has been accomplished using triarylbismuthanes in the presence of copper acetate and amine to give products 3 and 6 in excellent yield. Arylation on N2 after selective deprotection of derivatives with alkyl or aryl substituents on N1, resulting in compounds 8 and 9, is also demonstrated. Furthermore, other products derived from these reagents with free N-alkyl and N-aryl functions undergo the same reaction to give substances such as 10 and 11. As a result, the scope of the original hydrazine reagents has been further extended. A few reference compounds have also been prepared directly from phenylhydrazine.
- Loog,Maeorg,Ragnarsson
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p. 1591 - 1597
(2007/10/03)
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- Synthesis of fused 1,2,5-triazepine-1,5-diones and some N2- and N3-substituted derivatives: Potential conformational mimetics for cis-peptidyl prolinamides
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The synthesis of a new fused 1,2,5-triazepine-1,5-dione heterocycle, which is expected to mimic structural features of cis-peptldyl prolinamides, is described. The required parent heterocycle, corresponding to cis-glycy-(2S)-prolinamide, has been prepared in good yield by the cyclisation of N-(2-bromoacetylprolyl)-hydrazine which is itself generated in situ from the bromoacetyl proline methyl ester. Analogues corresponding to cis-(2R)-alanyl- and cis-(2S)-alanyl-(2S)-prolinamide have been similarly prepared from the appropriate N-(2-bromopropionyl)proline methyl esters and hydrazine hydrate where the cyclisation step, involving the displacement of bromide, has been shown to occur with inversion of configuration at C-2 of the propionyl moiety. Acylation at the N-3 position of the triazepine is equivalent to N-terminal acylation of the residue preceding the proline residue in cis-aminoacyl prolinamides. This has been achieved without incident using standard peptide coupling procedures. Extension at the 'C-terminal' has been achieved by preparing elaborated hydrazine precursors which are reacted with suitably activated esters of N-α-halogenoacylprolines, prior to cyclisation, to give the required fused triazepine dione. Thus it is possible to prepare constrained cis-peptidyl prolyl peptide mimetics of defined stereochemistry based upon this new triazepine dione in which all of the non-proline residues can be varied.
- Lenman, Morag M.,Lewis, Arwel,Gani, David
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p. 2297 - 2311
(2007/10/03)
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