- Structure and reactivity of benzoylnitrene radical anion in the gas phase
-
(Chemical Equation Presented) The open-shell benzoylnitrene radical anion, readily generated by electron ionization of benzoylazide, undergoes unique chemical reactivity with radical reagents and Lewis acids in the gas phase. Reaction with nitric oxide, NO, proceeds by loss of N2 and formation of benzoate ion. This novel reaction is also observed to occur with phenylnitrene anion, forming phenoxide. Similar reactivity was observed in the reaction between benzoylnitrene radical anion and NO2, forming benzoate ion and nitrous oxide. Electronic structure calculations indicate that the reaction has a high-energy barrier that is overcome by the energy released by bond formation. Benzoylnitrene radical anion also transfers oxygen anion to NO and NO2 as well as to CS2 and SO2. In contrast, phenylnitrene anion reacts with carbon disulfide by C+ or CS+ abstraction, forming S- or S2-. Electronic structure calculations indicate that benzoylnitrene in the ground state resembles a slightly polarized benzoate anion, but with a free radical localized on the nitrogen.
- Wijeratne, Neloni R.,Wenthold, Paul G.
-
-
Read Online
- Synthesis of Cyclic N-Acyl Amidines by [3 + 2] Cycloaddition of N-Silyl Enamines and Activated Acyl Azides
-
In this study, we describe the synthesis of cyclic N-acyl amidines from readily available N-heteroarenes. The synthetic methodology utilized the versatile N-silyl enamine intermediates from the hydrosilylation of N-heteroarenes for the [3 + 2] cycloaddition reaction step. We evaluated various acyl azides and selected an electronically activated acyl azide, thereby achieving a reasonable yield of cyclic N-acyl amidines. We analyzed the relationship between the reactivity of each step and the electronic nature of substrates using in situ nuclear magnetic resonance spectroscopy. In addition, we demonstrated gram-scale synthesis using the proposed methodology.
- Jo, Dong Geun,Joung, Seewon,Kim, Changeun,Lee, Sinjae,Yun, Sooyeon
-
supporting information
(2022/03/17)
-
- Synthesis of Acyl Phosphoramidates Employing a Modified Staudinger Reaction
-
A one-step synthesis of acyl phosphoramidates from a variety of functionalized acyl azides has been developed employing trimethylsilyl chloride as an activating agent in a modified Staudinger reaction. The methodology was further adapted to include the in situ generation of the acyl azides from a diverse selection of carboxylic acids and hydrazide starting synthons. The reaction scope was extended to include the synthesis of imidodiphosphates and the natural product Microcin C.
- Currie, Iain,Sleebs, Brad E.
-
supporting information
p. 464 - 468
(2021/02/03)
-
- Unravelling the potency of triazole analogues for inhibiting α-synuclein fibrillogenesis andin vitrodisaggregation
-
A series of triazole-based compounds was synthesized using a click chemistry approach and evaluated for the inhibition of α-synuclein (α-syn) fibrillogenesis and its disaggregation. CompoundsTr3,Tr7,Tr12,Tr15, andTr16exhibited good effect in inhibiting α-
- Maqbool, Mudasir,Gadhavi, Joshna,Singh, Anju,Hivare, Pravin,Gupta, Sharad,Hoda, Nasimul
-
supporting information
p. 1589 - 1603
(2021/03/01)
-
- Deoxygenative Amination of Azine-N-oxides with Acyl Azides via [3 + 2] Cycloaddition
-
A transition-metal-free deoxygenative C-H amination reaction of azine-N-oxides with acyl azides is described. The initial formation of an isocyanate from the starting acyl azide via a Curtius rearrangement can trigger a [3 + 2] dipolar cycloaddition of polar N-oxide fragments to generate the aminated azine derivative. The applicability of this method is highlighted by the late-stage and sequential amination reactions of complex bioactive compounds, including quinidine and fasudil. Moreover, the direct transformation of aminated azines into various bioactive N-heterocycles illustrates the significance of this newly developed protocol.
- Ghosh, Prithwish,Han, Sang Hoon,Han, Sangil,Kim, Dongeun,Kim, In Su,Kim, Saegun,Kwon, Na Yeon,Mishra, Neeraj Kumar
-
p. 2476 - 2485
(2020/03/13)
-
- Heterogeneous photocatalysis of azides: Extending nitrene photochemistry to longer wavelengths
-
The photodecomposition of azides to generate nitrenes usually requires wavelengths in the 300 nm region. In this study, we show that this reaction can be readily performed in the UVA region (368 nm) when catalyzed by Pd-decorated TiO2. In aqueous medium the reaction leads to amines, with water acting as the H source; however, in non-protic and non-nucleophilic media, such as acetonitrile, nitrenes recombine to yield azo compounds, while azirine-mediated trapping occurs in the presence of nucleophiles. The heterogeneous process facilitates catalyst separation while showing great chemoselectivity and high yields.
- Argüello, Juan E.,Lanterna, Anabel E.,Lemir, Ignacio D.,Scaiano, Juan C.
-
supporting information
p. 10239 - 10242
(2020/10/02)
-
- Synthesis of: N -methylated amines from acyl azides using methanol
-
The transformation of acyl azide derivatives into N-methylamines was developed using methanol as the C1 source via the one-pot Curtius rearrangement and borrowing hydrogen methodology. Following this protocol, various functionalised N-methylated amines were synthesized using the (NNN)Ru(ii) complex from carboxylic acids via an acyl azide intermediate. Several kinetic studies and DFT calculations were carried out to support the mechanism and also to determine the role of the Ru(ii) complex and base in this transformation.
- Chakrabarti, Kaushik,Dutta, Kuheli,Kundu, Sabuj
-
supporting information
p. 5891 - 5896
(2020/08/21)
-
- Copper-Catalyzed C(sp3)?H Amidation: Sterically Driven Primary and Secondary C?H Site-Selectivity
-
Undirected C(sp3)?H functionalization reactions often follow site-selectivity patterns that mirror the corresponding C?H bond dissociation energies (BDEs). This often results in the functionalization of weaker tertiary C?H bonds in the presence of stronger secondary and primary bonds. An important, contemporary challenge is the development of catalyst systems capable of selectively functionalizing stronger primary and secondary C?H bonds over tertiary and benzylic C?H sites. Herein, we report a Cu catalyst that exhibits a high degree of primary and secondary over tertiary C?H bond selectivity in the amidation of linear and cyclic hydrocarbons with aroyl azides ArC(O)N3. Mechanistic and DFT studies indicate that C?H amidation involves H-atom abstraction from R-H substrates by nitrene intermediates [Cu](κ2-N,O-NC(O)Ar) to provide carbon-based radicals R. and copper(II)amide intermediates [CuII]-NHC(O)Ar that subsequently capture radicals R. to form products R-NHC(O)Ar. These studies reveal important catalyst features required to achieve primary and secondary C?H amidation selectivity in the absence of directing groups.
- Bakhoda, Abolghasem (Gus),Jiang, Quan,Badiei, Yosra M.,Bertke, Jeffery A.,Cundari, Thomas R.,Warren, Timothy H.
-
supporting information
p. 3421 - 3425
(2019/02/14)
-
- Visible Light-Induced Regioselective Cycloaddition of Benzoyl Azides and Alkenes to Yield Oxazolines
-
Visible light catalysis allows the regioselective synthesis of oxazolines in high yields. The mild photosensitized manifold leverages the intermolecular formation of oxazolines with a wide functional group tolerance on both benzoyl azides and alkenes part
- Bellotti, Peter,Brocus, Julien,El Orf, Fatima,Selkti, Mohamed,K?nig, Burkhard,Belmont, Philippe,Brachet, Etienne
-
supporting information
p. 6278 - 6285
(2019/05/24)
-
- Aryl Azides as Forgotten Electrophiles in the Van Leusen Reaction: A Multicomponent Transformation Affording 4-Tosyl-1-arylimidazoles
-
Considering aryl azides as electrophilic partners for the TosMIC mediated Van Leusen reaction, a novel multicomponent synthesis of 4-tosyl-1-arylimidazoles is reported. In this transformation, two molecules of TosMIC participate in the reaction mechanism
- Necardo, Cristiana,Alfano, Antonella Ilenia,Del Grosso, Erika,Pelliccia, Sveva,Galli, Ubaldina,Novellino, Ettore,Meneghetti, Fiorella,Giustiniano, Mariateresa,Tron, Gian Cesare
-
p. 16299 - 16307
(2019/12/27)
-
- Direct conversion of carboxylic acids to various nitrogen-containing compounds in the one-pot exploiting curtius rearrangement
-
Herein we report, a single-pot multistep conversion of inactivated carboxylic acids to various N-containing compounds using a common synthetic methodology. The developed methodology rendered the use of carboxylic acids as a direct surrogate of primary amines, for the synthesis of primary ureas, secondary/tertiary ureas, O/S-carbamates, benzoyl ureas, amides, and N-formyls, exploiting the Curtius reaction. This approach has a potential to provide a diversified library of N-containing compounds, starting from a single carboxylic acid, based on the selection of the nucleophile.
- Kumar, Arun,Kumar, Naveen,Sharma, Ritika,Bhargava, Gaurav,Mahajan, Dinesh
-
p. 11323 - 11334
(2019/09/10)
-
- Tert -Butyl nitrite mediated nitrogen transfer reactions: Synthesis of benzotriazoles and azides at room temperature
-
A conversion of o-phenylenediamines into benzotriazoles was achieved at room temperature using tert-butyl nitrite. The optimized conditions are also well suited for the transformation of sulfonyl and acyl hydrazines into corresponding azides. This protocol does not require any catalyst or acidic medium. The desired products were obtained in excellent yields in a short span of time.
- Azeez, Sadaf,Chaudhary, Priyanka,Sureshbabu, Popuri,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
-
supporting information
p. 6902 - 6907
(2018/10/02)
-
- Palladium-Catalyzed One-Pot Synthesis of N -Sulfonyl, N -Phosphoryl, and N -Acyl Guanidines
-
An efficient palladium-catalyzed cascade reaction of azides with isonitrile and amines is presented; it offers an alternative facile approach toward N -sulfonyl-, N -phosphoryl-, and N -acyl-functionalized guanidines in excellent yield. These series of substituted guanidines exhibit potential biological and pharmacological activities. In addition, the less reactive intermediate benzoyl carbodiimide could be isolated by silica gel column flash chromatography in moderate yield.
- Qiao, Guanyu,Zhang, Zhen,Huang, Baoliang,Zhu, Liu,Xiao, Fan,Zhang, Zhenhua
-
supporting information
p. 330 - 340
(2018/01/12)
-
- Iridium(III)-Catalyzed Regiocontrolled Direct Amidation of Isoquinolones and Pyridones
-
Iridium(III)-catalyzed highly regiocontrolled C3/C8 amidation of isoquinolones and C6 amidation of 2-pyridones has been successfully accomplished with various azides. The optimized method is operationally simple with a broad substrate scope. The protocol has been found to be scalable. (Figure presented.).
- Das, Debapratim,Samanta, Rajarshi
-
supporting information
p. 379 - 384
(2017/12/26)
-
- Iridium(III)-Catalyzed Selective and Mild C-H Amidation of Cyclic N-Sulfonyl Ketimines with Organic Azides
-
A general protocol for iridium catalyzed direct C?H amidation of cyclic N-sulfonyl ketimines using sulfonyl, acyl and aryl azides as nitrogen source is reported herein. The reaction takes place at room temperature with acyl and aryl azides, while an elevated temperature needed with sulfonyl azides to furnish aminated sultams in excellent yields with complete chemo and regioselectivity, thus providing a robust and environmentally benign process to the synthesis of aminosultams. (Figure presented.).
- Maraswami, Manikantha,Chen, Gang,Loh, Teck-Peng
-
supporting information
p. 416 - 421
(2017/11/13)
-
- Synthesis of Acyl Azides from 1,3-Diketones via Oxidative Cleavage of Two C-C Bonds
-
A metal-free PhI(OAc)2-mediated method for the synthesis of acyl azides through oxidative cleavage of 1,3-diketones is described. This method is shown to have a broad substrate scope, providing a useful tool for multiproduct synthesis in a single procedure. A possible reaction pathway is proposed based on mechanistic studies.
- Yu, Tian-Yang,Zheng, Zhao-Jing,Dang, Tong-Tong,Zhang, Fang-Xia,Wei, Hao
-
p. 10589 - 10594
(2018/09/06)
-
- Electrophilic Activation of Carboxylic Anhydrides for Nucleophilic Acylation Reactions
-
Nucleophilic acylation of symmetrical carboxylic anhydrides has inherited limitation of reaction efficiency along with relatively poor reactivity. Traditionally, one equivalent carboxylic acid is generated during nucleophilic acylation of a symmetrical anhydride, which always limits the yield of final product to 50percent or less. This is a major drawback, which discourages the use of anhydrides for laboratory or industrial applications. Electrophilic activation of carboxylic anhydride using methanesulfonyl chloride is found to be an efficient method for nucleophilic acylation, which increases product yield by restricting the formation of corresponding acid as a side product. The developed protocol found to be a mild and high yielding methodology for one-pot nucleophilic acylation of carboxylic anhydrides with several type of N- and S-nucleophiles demonstrating appreciable functional group tolerance.
- Kumar, Varun,Kumar, Yashwant,Lal Meena, Chhuttan,Mahajan, Dinesh,Rana, Anil,Sharma, Nidhi
-
p. 3902 - 3910
(2018/09/29)
-
- Synthesis of Amines, Carbamates and Amides by Multi-Step Continuous Flow Synthesis
-
We report the continuous flow synthesis of acyl azides in various continuous flow systems and demonstrate that liquid–liquid separation may be incorporated to prepare anhydrous solutions of the acyl azide, which may be subsequently reacted with appropriate nucleophiles to prepare amines, carbamates and amides within a fully integrated multi-step process in high yields (> 80 %). Interesting effects were also observed when preparing carbamates with long chain alcohols, whereby as the chain length of the alcohol increased the products could be made in high yield even without incorporation of the liquid–liquid separation module.
- Sagandira, Cloudius R.,Watts, Paul
-
supporting information
p. 6554 - 6565
(2017/10/09)
-
- Visible light sensitization of benzoyl azides: Cascade cyclization toward oxindoles: Via a non-nitrene pathway
-
Visible light sensitization of benzoyl azides was examined in reaction with N-phenylmethacrylamides to afford biologically important oxindoles and spirooxindoles via a cascade cyclization under mild reaction conditions. Mechanistic studies suggested a non-nitrene pathway, where triplet benzoyl azides act as the reactive intermediate.
- Bagal, Dattatraya B.,Park, Sung-Woo,Song, Hyun-Ji,Chang, Sukbok
-
supporting information
p. 8798 - 8801
(2017/08/09)
-
- An investigation on practical synthesis of carboxylic acid derivatives using p-toluenesulfonyl chloride
-
Carboxylic acid derivatives are well recognized as important class of reagents frequently used in the preparation of a variety of fine or special chemicals such as amides, esters, peptides, drugs, and dyes. Although several methods were developed for the preparation of these compounds, many of them present difficulties, including low yield, high reaction temperature, harsh reaction conditions, tedious work-up, and incompatibility with scale-up. Methods: The synthesis of carboxylic anhydrides is developed through the reaction of carboxylic acids with TsCl in the presence of K2CO3 and acetonitrile as a solvent under ultrasound irradiation and conventional conditions. In addition, one-pot synthesis of acyl azides was carried out in the presence of produced carboxylic anhydrides and the addition of sodium azide under identical condition. Results: A series of carboxylic anhydrides and acyl azides were synthesized using TsCl under ultrasound irradiation and conventional stirring with simple procedure, mild reaction conditions, high yields, and scale-up ability without any restriction. In most cases, the reaction under ultrasound irradiation was better in both yields and the reaction times compared to the conventional method. Conclusion: A convenient method has been developed for the preparation of carboxylic anhydrides and acyl azides under ultrasound irradiation and conventional stirring. The present method is practical and a highly effective alternative for previous reports. The major advantages of this method are: (i) simplicity of the procedure (ii) high yields and high purity of product (iii) scale-up capacity without considerable limitation in conventional system. Under ultrasound irradiation short reaction times as compared to conventional method are observed; yields are comparable to or better than conventional method.
- Eskandari, Parvin,Kazemi, Foad
-
p. 431 - 439
(2017/07/24)
-
- Pathways in the Degradation of Geminal Diazides
-
The degradation of geminal diazides is described. We show that diazido acetates are converted into tetrazoles through the treatment with bases. The reaction of dichloro ketones with azide anions provides acyl azides, through in situ formation of diazido ketones. We present experimental and theoretical evidence that both fragmentations may involve the generation of acyl cyanide intermediates. The controlled degradation of terminal alkynes into amides (by loss of one carbon) or ureas (by loss of two carbons) is also shown.
- Holzschneider, Kristina,H?ring, Andreas P.,Haack, Alexander,Corey, Daniel J.,Benter, Thorsten,Kirsch, Stefan F.
-
p. 8242 - 8250
(2017/08/14)
-
- Cleavage of 1,3-dicarbonyls through oxidative amidation
-
A mild and convenient protocol for the oxidative cleavage of 1,3-diketone compounds is described. Under metal-free conditions, the method converts the 1,3-dicarbonyls into amides when treated with (nBu4N)N3 and iodine in the presence of an amine at room temperature. Using this method, a range of 1,3-dicarbonyls with various structural motifs including sterically demanding substituents and ordinary functional groups were easily fragmented, and it is demonstrated that cyclic 1,3-dicarbonyls can be directly transformed into acyclic diamides through ring-opening. Initial mechanistic studies show that diazidation of the enol form is followed by nucleophilic substitution with the amine.
- Biallas, Phillip,H?ring, Andreas P.,Kirsch, Stefan F.
-
p. 3184 - 3187
(2017/04/21)
-
- Iridium(III)-Catalyzed Regioselective Intermolecular Unactivated Secondary Csp3?H Bond Amidation
-
For the first time, a highly regioselective intermolecular sulfonylamidation unactivated secondary Csp3?H bond has been achieved using IrIIIcatalysts. The introduced N,N’-bichelating ligand plays a crucial role in enabling iridium–nitrene insertion into a secondary Csp3?H bond via an outer-sphere pathway. Mechanistic studies and density functional theory (DFT) calculations demonstrated that a two-electron concerted nitrene insertion was involved in this Csp3?H amidation process. This method tolerates a broad range of linear and branched-chain N-alkylamides, and provides efficient access to diverse γ-sulfonamido-substituted aliphatic amines.
- Xiao, Xinsheng,Hou, Cheng,Zhang, Zhenhui,Ke, Zhuofeng,Lan, Jianyong,Jiang, Huanfeng,Zeng, Wei
-
supporting information
p. 11897 - 11901
(2016/11/16)
-
- Preferred Binding of Carboxylates by Chiral Urea Derivatives Containing α-Phenylethyl Group
-
An efficient, simple protocol for the synthesis of a new family of chiral ureas 1 – 4 is described. The binding properties of 1 – 4 toward different anion (acetate, benzoate, fluoride, and chloride) have been studied by1H-NMR titration and have been observed in the case of 4 is a selective receptor for acetate. The theoretical calculation M06/6-311+G(d,p) helped us explain the binding properties observed. The most interesting observation is that this calculated structure is consistent with expected, based on the concept of allylic 1,3-strain (A1,3strain). When chiral caboxylates were studied, urea 1 was the best in discriminating between enantiomers.
- Cortés-Hernández, Mayra,Rojas-Lima, Susana,Hernández-Rodríguez, Marcos,Cruz-Borbolla, Julián,López-Ruiz, Heraclio
-
p. 416 - 424
(2016/07/06)
-
- Sulfur imidations by light-induced ruthenium-catalyzed nitrene transfer reactions
-
N-Acyl nitrenes have been generated from a range of heterocyclic precursors, and their applications in light-induced ruthenium-catalyzed sulfur imidations have been studied. Analyzing the reaction scope and determining the structural requirements of the in situ formed electrophilic nitrogen species for effective nitrene transfer allowed a mechanistic scheme to be proposed. The mechanistic conclusions were substantiated by the identification of potential intermediates.
- Bizet, Vincent,Bolm, Carsten
-
supporting information
p. 2854 - 2860
(2015/07/01)
-
- Visible light C-H amidation of heteroarenes with benzoyl azides
-
Benzoyl azides were used for the direct and atom economic C-H amidation of electron rich heteroarenes in the presence of phosphoric acid, a photocatalyst and visible light. Hetero-aromatic amides are obtained in good yields at very mild reaction conditions with dinitrogen as the only by-product. The reaction allows the use of aryl-, heteroaryl- or alkenyl acyl azides and has a wide scope for heteroarenes, including pyrroles, indole, furan, benzofuran and thiophene giving good regio-selectivities and yields.
- Brachet,Ghosh,Ghosh,K?nig
-
supporting information
p. 987 - 992
(2015/02/19)
-
- Unprecedented Transformation of a Directing Group Generated in Situ and Its Application in the One-Pot Synthesis of 2-Alkenyl Benzonitriles
-
An unprecedented protocol for the transformation of benzoyl azides into benzonitrile derivatives via iminophosphoranes generated in situ is described. The strategy was successfully applied to the de-novo synthesis of 2-alkenylated benzonitrile derivatives from benzoyl azides through ortho CH activation/alkenylation followed by subsequent rearrangement. The salient features of this protocol involve incorporation of two important functionalities through cyanation and olefination in one pot under mild reaction conditions by using a less expensive Ru catalyst. The mechanism was established by isolating and characterising (using 31PNMR) an intermediate with two ortho functionalities, iminophosphorane and olefin, under specific reaction conditions. Directly functional! Cyanation and olefination was accomplished in one pot from benzoyl azides through an unprecedented directing group transformation. The method generates benzonitriles and can be used for the synthesis of 2-alkenylated benzonitrile derivatives (see scheme).
- Kumar, Ravi,Arigela, Rajesh K.,Kundu, Bijoy
-
p. 11807 - 11812
(2015/08/11)
-
- Intramolecular rearrangement of α-azidoperoxides: An efficient synthesis of tert-butyl esters
-
An unprecedented intramolecular rearrangement of α-azidoperoxides, promoted by simple organic base to provide tert-butyl esters, has been presented. Further, a one-pot methodology consisting of in situ generation of the α-azidoperoxides from corresponding aldehydes followed by base-promoted rearrangement to obtain the desired ester has also been executed. Relevant mechanistic studies, to provide the proof for intramolecular alkoxy transfer, are investigated.
- Pramanik, Suman,Reddy, Reddy Rajasekhar,Ghorai, Prasanta
-
p. 1393 - 1396
(2015/03/30)
-
- Facile and Divergent Synthesis of Lamellarins and Lactam-Containing Derivatives with Improved Drug Likeness and Biological Activities
-
With the goal to improve the aqueous solubility of lamellarins, the lactone ring in their skeleton was replaced with a lactam moiety in azalamellarins. However, the reported synthetic route produced such derivatives in very low yields. Hence, this study focused on developing an efficient simplified total synthetic scheme that could furnish both azalamellarins and the parent lamellarins from the same pyrrole ester intermediates. Subsequent comparative profiling revealed that the introduced lactone-to-lactam replacement rendered these molecules less lipophilic, whereas their cancer cytotoxicity remained equipotent to that of the parent compounds. Interestingly, their inhibitory activity was significantly enhanced towards the multifaceted GSK-3β enzyme. Our results clearly demonstrate the therapeutic potential of this promising class of marine-derived natural products and justify their further development, especially into anticancer agents.
- Theppawong, Atiruj,Ploypradith, Poonsakdi,Chuawong, Pitak,Ruchirawat, Somsak,Chittchang, Montakarn
-
supporting information
p. 2631 - 2650
(2016/02/09)
-
- Orthogonal reactivity of acyl azides in C-H activation: Dichotomy between C-C and C-N amidations based on catalyst systems
-
The dual reactivity of acyl azides was utilized successfully in C-H activation by the choice of catalyst systems: while selective C-C amidation was achieved under thermal Rh catalysis, a Ru catalyst was found to mediate direct C-N amidation also highly se
- Shin, Kwangmin,Ryu, Jaeyune,Chang, Sukbok
-
supporting information
p. 2022 - 2025
(2014/05/06)
-
- Ceric ammonium nitrate (CAN) catalyzed modification of ketones via two C-C bond cleavages with the retention of the oxo-group
-
A simple ceric ammonium nitrate (CAN) catalyzed functionalization of ketones through double C-C bond cleavage strategy has been disclosed. This reaction provides a mild, practical method toward carbamoyl azides, which are versatile intermediates and building blocks in organic synthesis. Based on relevant mechanistic studies, a unique and plausible C-C bond and N-O bond cleavage process is proposed, where the oxyamination intermediate plays an important role in this reaction.
- Feng, Peng,Sun, Xiang,Su, Yijin,Li, Xinyao,Zhang, Li-He,Shi, Xiaodong,Jiao, Ning
-
supporting information
p. 3388 - 3391
(2014/07/08)
-
- The challenge of palladium-catalyzed aromatic azidocarbonylation: From mechanistic and catalyst deactivation studies to a highly efficient process
-
Azidocarbonylation of iodoarenes with CO and NaN3, a novel Heck-type carbonylation reaction, readily occurs in an organic solvent-H 2O biphasic system to furnish aroyl azides at room temperature and 1 atm. The reaction is catalyzed by Xantphos-Pd and exhibits high functional group tolerance. The catalyst deactivation product, [(Xantphos)PdI2], can be reduced in situ with PMHS to Pd(0) to regain catalytic activity. In this way, the catalyst loading has been lowered to 0.2% without any losses in selectivity at nearly 100% conversion to synthesize a series of aroyl azides in 80-90% isolated yield on a gram scale. Alternatively, the ArCON3 product can be used without isolation for further transformations in situ, e.g., to isocyanates, ureas, benzamides, and iminophosphoranes. A detailed experimental and computational study has identified two main reaction pathways for the reaction. For both routes, Ar-I oxidative addition to Pd(0) is the rate-determining step. In the presence of CO in excess, the Ar-I bond is activated by the less electron-rich Pd center of a mixed carbonyl phosphine complex. Under CO-deficient conditions, a slightly lower energy barrier pathway is followed that involves Ar-I oxidative addition to a more reactive carbonyl-free (Xantphos)Pd0 species. Mass transfer in the triphasic liquid-liquid-gas system employed for the reaction plays an important role in the competition between these two reaction channels, uniformly leading to a common aroyl azido intermediate that undergoes exceedingly facile ArCO-N 3 reductive elimination. Safety aspects of the method have been investigated.
- Miloserdov, Fedor M.,McMullin, Claire L.,Belmonte, Marta Martinez,Benet-Buchholz, Jordi,Bakhmutov, Vladimir I.,Macgregor, Stuart A.,Grushin, Vladimir V.
-
supporting information
p. 736 - 752
(2014/03/21)
-
- Reactions of acyl azides with secondary amines in the presence of copper(II) acetate
-
The nucleophilic substitution of the azide group in acyl azides for secondary amines in the presence of copper(II) acetate was studied. The formation of the corresponding amides and copper(II) azide in the course of the reaction was observed. The shift of the absorption band of stretching vibrations of the azide group was observed in the IR spectra of the reaction products, which could be explained by the intermediate formation of a complex of acyl azide with the amine complex of copper(II) acetate and by its decomposition to form copper(II) azide and the corresponding amide. A blue-green color of the solution characteristic of copper(II) acetate changed in the course of the reaction to the brown color of a solution of copper(II) azide.
- Budruev,Sinjagina
-
p. 1366 - 1370
(2014/05/06)
-
- β-diketiminato nickel imides in catalytic nitrene transfer to isocyanides
-
The β-diketiminato nickel(I) species [Me3NN]Ni(2-picoline) (1) serves as an efficient catalyst for carbodiimide (RN=C=NR′) formation in the reactions of a range of organoazides N3R with isocyanides R′NC. [Me3NN]Ni(CNR)2 (R = tBu, Ar (Ar = 2,6-Me2C6H3)) species provide carbodiimides RN=C=NAr′ upon reaction with Ar′N3 (Ar′ = 3,5-Me2C6H3). Nitrene transfer takes place via the intermediacy of nickel imides. Reaction of [MexNN]Ni(2-picoline) (x = 2 or 3) with Ar′N3 gives the new dinickel imides {[Me xNN]Ni}2(μ-NAr′) (4 (x = 3) and 5 (x = 2)) as deep purple, diamagnetic substances. The X-ray structure of {[Me 2NN]Ni}2(μ-NAr′) (5) features short Ni-N imide distances of 1.747(2) and 1.755(2) A along with a short Ni-Ni distance of 2.7210(3) A. These dinickel imides 4 and 5 react stoichiometrically with tBuNC to provide the corresponding carbodiimides tBuN=C=NAr′ in good yield. Azide transfer takes place upon reaction of 1 with TMS-N3 to give the square planar nickel(II) azide [Me3NN]Ni(N3)(2-picoline) (7). Stoichiometric reaction of dinickel dicarbonyl {[Me3NN]Ni} 2(μ-CO)2 with organoazides such as Ar′N 3 is sluggish, indicating that 1 is not an efficient catalyst for nitrene transfer from organoazides to CO to form isocyanates RN=C=O.
- Wiese, Stefan,Aguila, Mae Joanne B.,Kogut, Elzbieta,Warren, Timothy H.
-
supporting information
p. 2300 - 2308
(2013/06/27)
-
- Ir(III)-catalyzed mild C-H amidation of arenes and alkenes: An efficient usage of acyl azides as the nitrogen source
-
Reported herein is the development of the Ir(III)-catalyzed direct C-H amidation of arenes and alkenes using acyl azides as the nitrogen source. This procedure utilizes an in situ generated cationic half-sandwich iridium complex as a catalyst. The reaction takes place under very mild conditions, and a broad range of sp2 C-H bonds of chelate group-containing arenes and olefins are smoothly amidated with acyl azides without the intervention of the Curtius rearrangement. Significantly, a wide range of reactants of aryl-, aliphatic-, and olefinic acyl azides were all efficiently amidated with high functional group tolerance. Using the developed approach, Z-enamides were readily accessed with a complete control of regio- and stereoselectivity. The developed direct amidation proceeds in the absence of external oxidants and releases molecular nitrogen as a single byproduct, thus offering an environmentally benign process with wide potential applications in organic synthesis and medicinal chemistry.
- Ryu, Jaeyune,Kwak, Jaesung,Shin, Kwangmin,Lee, Donggun,Chang, Sukbok
-
supporting information
p. 12861 - 12868
(2013/09/23)
-
- Copper-mediated amidation of alkenylzirconocenes with acyl azides: Formation of enamides
-
Copper-mediated amidation of alkenylzirconocenes generated in situ from alkynes and zirconocenes with acyl azides is accomplished under mild conditions. The reaction can be used to prepare various enamides.
- Liu, Hailan,Zhou, Yiqing,Yan, Xiaoyu,Chen, Chao,Liu, Qingbin,Xi, Chanjuan
-
supporting information
p. 5174 - 5177
(2013/11/06)
-
- Direct and facile synthesis of acyl azides from carboxylic acids using the trichloroisocyanuric acid-triphenylphosphine system
-
A mild, efficient, and practical method for the one-step synthesis of acyl azides from carboxylic acids using a safe and inexpensive mixed reagent, trichloroisocyanuric acid-triphenylphosphine, is described.
- Akhlaghinia, Batool,Rouhi-Saadabad, Hamed
-
p. 181 - 185
(2013/05/09)
-
- Novel VEGFR-2 kinase inhibitors identified by the back-to-front approach
-
We report a novel VEGFR-2 inhibitor, developed by the back-to-front approach. Docking experiments indicated that the 3-chloromethylphenylurea motif of the lead compound occupied the back pocket of VEGFR-2 kinase. An attempt was made to enhance the binding affinity of 1 by expanding the structure to access the front pocket using a triazole linker. A library of 1,4-(disubstituted)-1H-1, 2,3-triazoles were screened in silico, and one compound (VH02) was identified with an IC50 against VEGFR-2 of 0.56 μM. VH02 showed antiangiogenic effects, inhibiting tube formation in HUVEC cells (EA.hy926) at 0.3 μM, 13 times lower than its cytotoxic dose. These enzymatic and cellular activities suggest that VH02 has potential as a lead for further optimization.
- Sanphanya, Kingkan,Wattanapitayakul, Suvara K.,Phowichit, Suwadee,Fokin, Valery V.,Vajragupta, Opa
-
supporting information
p. 2962 - 2967
(2013/06/27)
-
- Design and synthesis of novel stiripentol analogues as potential anticonvulsants
-
A series of stiripentol (STP) analogues namely, 2-[(1E)-1-(1,3-benzodioxol- 5-yl)-4,4-dimethylpent-1-en-3-ylidene]-N-(aryl/H)hydrazinecarboxamides 7a-h, (±)-(5RS)-N-(aryl/H)-(1,3-benzodioxol-5-yl)-3-tert-butyl-4, 5-dihydro-1H-pyrazole-1-carboxamides (±)-8a-h, and (±)-[(5RS)-(1, 3-benzodioxol-5-yl)-3-tert-butyl-4,5-dihydro-1H-pyrazol-1-yl](aryl)methanones (±)-13a-f was synthesized by adopting appropriate synthetic routes and was pharmacologically evaluated in the preliminary anticonvulsant screens. The selected bioactive new chemical entities were subjected to ED50 determination and neurotoxicity evaluation. The most active congeners are 7h in MES screen and (±)-13b in scPTZ screen which displayed ED50 values of 87 and 110 mg/kg, respectively, as compared to that of STP (ED 50 = 277.7 and 115 mg/kg in MES and scPTZ, respectively).
- Aboul-Enein, Mohamed N.,El-Azzouny, Aida A.,Attia, Mohamed I.,Maklad, Yousreya A.,Amin, Kamilia M.,Abdel-Rehim, Mohamed,El-Behairy, Mohammed F.
-
experimental part
p. 360 - 369
(2012/03/11)
-
- Novel tetrahydropyrido[1,2-a]isoindolone derivatives (valmerins): Potent cyclin-dependent kinase/glycogen synthase kinase 3 inhibitors with antiproliferative activities and antitumor effects in human tumor xenografts
-
The development of CDK and GSK3 inhibitors has been regarded as a potential therapeutic approach, and a substantial number of diverse structures have been reported to inhibit CDKs and GSK-3β in recent years. Only a few molecules have gone through or are currently undergoing clinical trials as CDK and GSK inhibitors. In this paper, we prepared valmerins, a new family containing the tetrahydropyrido[1,2-a]isoindone core. The fused heterocycle was prepared with a straightforward synthesis that was functionalized by a (het)arylurea. Twelve valmerins inhibited the CDK5 and GSK3 with an IC50 100 nM. A semiquantitative kinase scoring was realized, and a cellular screening was done. At the end of our study, we investigated the in vivo potency of one valmerin. Mice exhibited good tolerance to our lead, which proved its efficacy and clearly blocked tumor growth. Valmerins appear also as good candidates for further development as anticancer agents.
- Boulahjar, Rajaa,Ouach, Aziz,Matteo, Chiurato,Bourg, Stephane,Ravache, Myriam,Guével, Rémy Le,Marionneau, Séverine,Oullier, Thibauld,Lozach, Olivier,Meijer, Laurent,Guguen-Guillouzo, Christiane,Lazar, Sa?d,Akssira, Mohamed,Troin, Yves,Guillaumet, Gérald,Routier, Sylvain
-
p. 9589 - 9606
(2013/01/16)
-
- Synthesis and evaluation of 1-(substituted)-3-prop-2-ynylureas as antiangiogenic agents
-
Novel urea derivatives of alkynes have been designed, synthesized, and evaluated as potential cancer therapeutics leads. The most active 1-((3-chloromethyl)phenyl)-3-prop-2-ynylurea (1) exhibited cytotoxic effect against HELA and MCF-7 cell lines with IC50 values of 1.55 μM and 1.48 μM, respectively. Further investigation on tube formation assay in human vein umbilical cells (HUVEC) demonstrated that 1 and methyl 4-(3-(3-ethynylureido)benzyloxy) benzoate (6) possess antiangiogenic activity, with minimum effective dose of 25 nM (for 1) and 6.25 μM (for 6). The ED 50 of 1 and 6 were found to be 0.26 μM and 17.52 μM, respectively. The results from in vitro tyrosine kinase assay indicated the EGFR inhibition of 1 over other kinases (VEGFR2, FGFR1 and PDGFRβ). The cytotoxicity of 1 against EGFR overexpressing cell line A431 (IC50 36 nM) was comparable to that of erlotinib. The binding mode of 1 from docking simulation in the EGFR active site revealed that the urea motif formed hydrogen bonding with Lys745, Thr854 and Asp855 in hydrophobic pocket of EGFR. Compound 1 is considered as a potential lead for further optimization.
- Sanphanya, Kingkan,Wattanapitayakul, Suvara K.,Prangsaengtong, Orawin,Jo, Michiko,Koizumi, Keiichi,Shibahara, Naotoshi,Priprem, Aroonsri,Fokin, Valery V.,Vajragupta, Opa
-
supporting information; experimental part
p. 3001 - 3005
(2012/06/04)
-
- One-pot, direct synthesis of acyl azides from carboxylic acids using Ph2PCl/I2/NaN3 reagent system
-
A mild, efficient and simple method for the preparation of acyl azides from carboxylic acids using chlorodiphenylphosphine in the presence of molecular iodine and sodium azide is described.
- Nowrouzi, Najmeh,Zareh Jonaghani, Mohammad
-
p. 442 - 445
(2012/05/20)
-
- Palladium-catalyzed aromatic azidocarbonylation
-
Aryl iodides smoothly react with NaN3 and CO in the presence of a Pd/Xantphos catalyst to give aroyl azides (ArCON3) in 75-92 % yield. The reaction occurs under mild reaction conditions (1 atm, 20-50 °C) and exhibits high functional-group tolerance. (Xantphos=9,9-dimethyl-4,5- bis(diphenylphosphino)xanthene)
- Miloserdov, Fedor M.,Grushin, Vladimir V.
-
supporting information; experimental part
p. 3668 - 3672
(2012/05/20)
-
- FeCl36H2O-Catalyzed acceleration of the acylation of sodium azide with n-acylbenzotriazoles
-
Catalyzed by ferric chloride hexahydrate (FeCl36H2O), the acylation of sodium azide with N-acylbenzotriazoles was greatly accelerated in a mixed solvent of acetone and water. Thus, good to excellent yields of a variety of acyl azides were obtained at room temperature in a short time. Furthermore, because of the complete conversion of N-acylbenzotriazoles and the easy removal of the by-product, purification by column chromatography was no longer required, which made the protocol suitable for large-scale preparation.
- Zhong, Zhiyun,Hu, Jieling,Wang, Xiaoxia,Liu, Junhua,Zhang, Longfeng
-
experimental part
p. 2461 - 2467
(2011/08/05)
-
- Facile one step synthesis of acyl azides and Nα-Fmoc/Boc/Z protected amino acid azides employing benzotriazole-1-yl-oxy-tris- (dimethylamino)-phosphonium hexafluorophosphate (BOP)
-
A simple route for the preparation of acyl azides from the corresponding carboxylic acids employing the peptide-coupling agent BOP is described. The procedure is simple, clean and high yielding. The chemistry is also extended to the preparation of several urethane protected amino acid azides (eight examples) as well.
- Vasantha,Sureshbabu, Vommina V.
-
scheme or table
p. 812 - 817
(2011/01/04)
-
- Direct synthesis of acyl azides from carboxylic acids using 2-azido-l,3-dimethylimidazolinium chloride
-
Acyl azides were directly synthesized from carboxylic acids by the treatment with 2-azido-l,3-dimethylimidazolinium chloride (ADMC, 1) and amine. This procedure resulted in acyl azides in good yields and was applied to the amidation of amino acid derivatives without racemization of the products.
- Kitamura, Mitsuru,Tashiro, Norifumi,Takamoto, Yusuke,Okauchi, Tatsuo
-
scheme or table
p. 731 - 733
(2011/01/08)
-
- T3P (propylphosphonic anhydride) mediated conversion of carboxylic acids into acid azides and one-pot synthesis of ureidopeptides
-
A general, mild, efficient, and environmentally benign protocol, which makes use of T3P as an acid activating agent for the direct synthesis of acid azides from carboxylic acids is described. Further, the protocol is employed for the one-pot synthesis of α-ureidopeptides starting from N-protected α-amino acids.
- Basavaprabhu,Narendra,Lamani, Ravi S.,Sureshbabu, Vommina V.
-
experimental part
p. 3002 - 3005
(2010/07/10)
-
- Oxidative amidation and azidation of aldehydes by NHC catalysis
-
Figure presented N-Heterocyclic carbene catalyzed oxidative amidations of various aldehydes to the corresponding hexafluoroisopropylesters by using the readily available organic oxidant A are described. The hexafluoroisopropylesters prepared in situ are shown to be highly useful active esters for amide bond formation. In addition, oxidative azidation of aldehydes is presented. These mild organocatalytic processes do not use any transition metal.
- De Sarkar, Suman,Studer, Armido
-
supporting information; experimental part
p. 1992 - 1995
(2010/07/10)
-
- Ph3P/Br2/n-Bu4NNO2 as an efficient system for the preparation of N-nitrosamines and azides
-
The combination PPh3/Br2/n-Bu4NNO2 was developed as a new reagent system for the efficient preparation of N-nitrosamines and azides from the corresponding amines and hydrazine derivatives, respectively, at 0 °C to room temperature, in excellent yields.
- Iranpoor, Nasser,Firouzabadi, Habib,Nowrouzi, Najmeh
-
p. 4242 - 4244
(2008/09/20)
-