- Selenium-assisted one-pot synthesis of carbodiimides from isocyanides and primary amines
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Reaction of isocyanides with primary amines in the presence of selenium and DBU, followed by introduction of molecular oxygen in refluxing THF affords carbodiimides in high yields.
- Fujiwara, Shin-Ichi,Matsuya, Takahiro,Maeda, Hajime,Shin-Ike, Tsutomu,Kambe, Nobuaki,Sonoda, Noboru
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- Carbodiimide Synthesis via Ti-Catalyzed Nitrene Transfer from Diazenes to Isocyanides
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Simple Ti imido halide complexes such as [Br2Ti(NtBu)py2]2 are competent catalysts for the synthesis of unsymmetrical carbodiimides via Ti-catalyzed nitrene transfer from diazenes or azides to isocyanides. Both alkyl and aryl isocyanides are compatible with the reaction conditions, although product inhibition with sterically unencumbered substrates sometimes limits the yield when diazenes are employed as the oxidant. The reaction mechanism has been investigated both experimentally and computationally, wherein a key feature is that the product release is triggered by electron transfer from an η2-carbodiimide to a Ti-bound azobenzene. This ligand-to-ligand redox buffering obviates the need for high-energy formally TiII intermediates and provides further evidence that substrate and product "redox noninnocence" can promote unusual Ti redox catalytic transformations.
- Beaumier, Evan P.,McGreal, Meghan E.,Pancoast, Adam R.,Wilson, R. Hunter,Moore, James T.,Graziano, Brendan J.,Goodpaster, Jason D.,Tonks, Ian A.
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- Electrochemical Synthesis of Carbodiimides via Metal/Oxidant-Free Oxidative Cross-Coupling of Amines and Isocyanides
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This work discloses an electrochemical oxidative cross-coupling of amines with aryl and aliphatic isocyanides. In an undivided cell, the reaction proceeds without involving any transition-metal catalyst, oxidant, or toxic reagents providing carbodiimides in good yields, thereby circumventing stoichiometric chemical oxidants, with H2 as the only byproduct. Moreover, carbodiimides were in situ converted into unsymmetrical ureas in moderate to good yields using an electricity ON-OFF strategy.
- Badsara, Satpal Singh,Jaiswal, Pradeep K.,Malviya, Bhanwar Kumar,Sharma, Siddharth,Verma, Ved Prakash
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supporting information
(2020/03/19)
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- Direct Assembly of Polysubstituted Propiolamidinates via Palladium-Catalyzed Multicomponent Reaction of Isocyanides
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A straightforward approach for the assembly of different polysubstituted propiolamidnates via palladium-catalyzed multicomponent reaction of isocyanides, haloalkynes, and amines has been reported in which the C(sp)-C(sp2) and C(sp2)a
- Li, Meng,Fang, Songjia,Zheng, Jia,Jiang, Huanfeng,Wu, Wanqing
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supporting information
p. 8439 - 8443
(2019/10/16)
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- Sequential Pd(0)/Fe(III) Catalyzed Azide-Isocyanide Coupling/Cyclization Reaction: One-Pot Synthesis of Aminotetrazoles
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A rapid and efficient synthesis of aminotetrazole from aryl azides, isocyanides, and TMSN3 is developed. The reaction is promoted by sequential Pd(0)/Fe(III) catalysis. The reaction sequence utilizes the Pd-catalyzed azide-isocyanide denitrogenative coupling reaction to generate unsymmetric carbodiimide in situ, which reacts with TMSN3 in the presence of FeCl3 in a single pot. The methodology has distinct advantages over traditional synthetic approaches where toxic Hg and Pb salts are employed at stoichiometric scale.
- Pathare, Ramdas S.,Ansari, Arshad J.,Verma, Sarika,Maurya, Anand,Maurya, Antim K.,Agnihotri, Vijai K.,Sharon, Ashoke,Pardasani, Ram T.,Sawant, Devesh M.
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supporting information
p. 9530 - 9537
(2018/08/03)
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- Synthesis of Diverse Nitrogen Heterocycles via Palladium-Catalyzed Tandem Azide–Isocyanide Cross-Coupling/Cyclization: Mechanistic Insight using Experimental and Theoretical Studies
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A rapid and elegant tandem azide–isocyanide cross-coupling/cyclization protocol has been developed based on a nitrene transfer reaction. The palladium-catalyzed ligand-free methodology led to the synthesis of three different heterocyclic scaffolds with excellent atom/step/redox economy. Studies based on first-principles-based quantum calculations and control experiments unraveled a concerted process of nitrene transfer reaction on isocyanides, ruling out the metallaaziridine intermediate reported earlier. This finding could pave the way for novel applications of nitrene transfer reactions to generate bioactive heterocycles. (Figure presented.).
- Ansari, Arshad J.,Pathare, Ramdas S.,Maurya, Antim K.,Agnihotri, Vijai K.,Khan, Shahnawaz,Roy, Tapta Kanchan,Sawant, Devesh M.,Pardasani, Ram T.
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supporting information
p. 290 - 297
(2017/12/07)
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- Cyclization of Alkyne-Azide with Isonitrile/CO via Self-Relay Rhodium Catalysis
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A self-relay rhodium(I)-catalyzed cyclization of alkyne-azides with two σ-donor/π-acceptor ligands (isonitriles and CO) to form sequentially multiple-fused heterocycle systems via tandem nitrene transformation and aza-Pauson-Khand cyclization has been dev
- Zhang, Zhen,Xiao, Fan,Huang, Baoliang,Hu, Jincheng,Fu, Bin,Zhang, Zhenhua
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supporting information
p. 908 - 911
(2016/03/15)
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- Ultrasonic-assisted synthesis of carbodiimides from N,N′-disubstituted thioureas and ureas
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A facile and efficient sonochemical method for the preparation of carbodiimides from their corresponding thioureas or ureas was described. Using Ph3P–I2 combination in the presence of triethylamine, various diaryl, aryl–alkyl, as well as dialkyl substituted substrates could be converted into carbodiimides in good-to-excellent yields within short reaction times under mild conditions with simple experimental setup. Graphical abstract: [Figure not available: see fulltext.]
- Duangkamol, Chuthamat,Pattarawarapan, Mookda,Phakhodee, Wong
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p. 1945 - 1949
(2016/10/21)
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- Palladium-catalyzed cross-coupling reaction of azides with isocyanides
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An efficient palladium-catalyzed cross-coupling reaction of azides with isocyanides is developed, providing a general synthetic route to unsymmetric carbodiimides with excellent yields. This method shows a broad substrate scope, including not only aryl azides, but also unactivated benzyl and alkyl azides. Furthermore, from readily available substrates, Pd-catalyzed coupling with a tandem amine insertion cascade to obtain unsymmetric trisubstituted guanidines has been achieved in a one-pot fashion.
- Zhang, Zhen,Li, Zongyang,Fu, Bin,Zhang, Zhenhua
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supporting information
p. 16312 - 16315
(2015/11/16)
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- Synthesis of carbodiimides by I2/CHP-mediated cross-coupling reaction of isocyanides with amines under metal-free conditions
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An I2/CHP-mediated cross-coupling reaction of isocyanides with readily accessible amines via C-N formation is described for carbodiimide synthesis in moderate to excellent yields. This represents a metal-free strategy for a coupling reaction of isocyanides with amines, and it provides an efficient approach for symmetric and unsymmetric functionalized carbodiimide derivative synthesis under mild conditions.
- Zhu, Tong-Hao,Wang, Shun-Yi,Tao, Yang-Qing,Ji, Shun-Jun
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supporting information
p. 1974 - 1977
(2015/04/27)
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- β-diketiminato nickel imides in catalytic nitrene transfer to isocyanides
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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.
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supporting information
p. 2300 - 2308
(2013/06/27)
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- Sustainable synthesis of diverse privileged heterocycles by palladium-catalyzed aerobic oxidative isocyanide insertion
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Heterocycles containing a guanidine moiety are of great importance in medicinal chemistry (Scheme 1).[1] As a result, several methods for the synthesis of these "privileged scaffolds" have been reported.[2, 3] Classical approaches, such as the addition of diamines to isothiocyanates followed by condensation and the coupling of diamines with cyanogen bromide,[2, 4] have some clear limitations, such as the availability and toxicity of reagents. Moreover, these procedures suffer from poor atom and/or step efficiency, thus making them unattractive from a sustainability point of view.
- Vlaar, Tj?stil,Cioc, Razvan C.,Mampuys, Pieter,Maes, Bert U. W.,Orru, Romano V. A.,Ruijter, Eelco
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supporting information
p. 13058 - 13061
(2013/02/26)
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- A mild, efficient approach for the synthesis of 1,5-disubstituted hydantoins
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An efficient and straightforward two-step procedure for the synthesis of N-1 alkyl/aryl-substituted hydantoins was developed, starting from easily available starting materials. The procedure envisages a highly reglospecific domino condensation/aza-Michael
- Olimpieri, Francesca,Bellucci, Maria Cristina,Volonterio, Alessandro,Zanda, Mateo
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scheme or table
p. 6179 - 6188
(2010/03/04)
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- One-pot syntheses of 5-amino-1-aryltetrazole derivatives
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A novel facile route for the introduction of 5-amino and 5-alkylamino substituents into 1-aryltetrazoles has been developed. A range of 5-amino-1-aryltetrazoles was obtained directly from the corresponding 1-aryltetrazoles in one pot by consecutive ring-opening, azidation and intramolecular cyclization. 5-Alkylamino-1-aryltetrazoles were formed by a similar mechanism from 1,4-disubstituted tetrazolium salts. An influence of the nature of aryl substituents and reaction conditions on the regioselectivity of the intramolecular cyclization of intermediate guanyl azides is revealed. Georg Thieme Verlag Stuttgart.
- Vorobiov, Andrey N.,Gaponik, Pavel N.,Petrov, Petr T.,Ivashkevich, Oleg A.
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p. 1307 - 1312
(2007/10/03)
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- Highly Enantioselective Synthesis of 1,3-Oxazolidin-2-imine Derivatives by Asymmetric Cycloaddition Reactions of Vinyloxiranes with Unsymmetrical Carbodiimides Catalyzed by Palladium(0) Complexes
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4-Vinyl-1,3-oxazoilidin-2-imine derivatives have been synthesized by cycloaddition reactions of 2-vinyloxiranes with unsymmetrical carbodiimides catalyzed by palladium(0) complexes in excellent total isolated yields. After reaction two compounds were alwa
- Larksarp, Chitchamai,Alper, Howard
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p. 6229 - 6233
(2007/10/03)
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- Synthesis and structure-activity relationships of novel phenylcyanoguanidine derivatives as potassium channel openers
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3,5-Di-substituted phenylcyanoguanidine derivatives with halogen, cyano, and/or nitro groups at the 3- and 5-positions of the benzene ring exhibited very strong smooth muscle relaxation activity in vitro, as compared to pinacidil. Among them, N-(3-chloro-5-cyanophenyl)-N'-cyano-N''-tert- pentylguanidine (5s) showed 27-fold more potent activity than pinacidil, and exhibited a stronger and more lasting antihypertensive effect than pinacidil by oral administration to spontaneously hypertensive rats. We propose a new pharmacophore model in which the essential factors for binding to the potassium channel are an NH and a bulky alkyl group.
- Yoshiizumi, Kazuya,Ikeda, Shoji,Goto, Katsumi,Morita, Tominori,Nishimura, Noriyasu,Sukamoto, Takayuki,Yoshino, Kohichiro
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p. 2042 - 2050
(2007/10/03)
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- Cycloaddition of N-Aryl-tert-butylketenimines to Both Nitrosobenzene and 2-Methyl-2-nitrosopropane
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Reactions of the ketenimines 1a, b with nitrosobenzene (2a) do not give the appropriate 1,2-oxazetidines such as 3Aa,b, but produce small amounts of the benzoxazoles 4a, b and the 1,4-benzoxazines 5Aa, b.However, from 1a-c and the nitrosoalkane 2b the analogous compounds 5Ba-c and/or 3Ba-c are formed (depending on conditions); mixtures of 1d-f and 2b afford 3Bd-f only.The heterocycles 4 and 5 are believed to arise through the intermediary cycloadduct 14/14'.
- Moderhack, Dietrich,Stolz, Karsten
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p. 3411 - 3421
(2007/10/02)
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- 1,1'-Thiocarbonyldi-2,2'-pyridone. A New Useful Reagent for Functional Group Conversions under Essentially Neutral Conditions
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1,1'-Thiocarbonyldi-2,2'-pyridone is a useful reagent for the preparation of nitriles, carbodiimides, cyclic thionocarbonates, and isothiocyanates and deoxygenation of alcohols under essentially neutral conditions.
- Kim, Sunggak,Yi, Kyu Yang
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p. 2613 - 2615
(2007/10/02)
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- DI-2-PYRIDYL THIONOCARBONATE. A NEW REAGENT FOR THE PREPARATION OF ISOTHIOCYANATES AND CARBODIIMIDES.
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Reaction of amines with di-2-pyridyl thionocarbonate affords the corresponding isothiocyanates at room temperature, while reaction of N,N'-disubstituted thioureas with di-2-pyridyl thionocarbonate in the presence of 4-dimethylaminopyridine as a catalyst affords the corresponding carbodiimides in high yields.
- Kim, Sunggak,Yi, Kyu Yang
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p. 1661 - 1664
(2007/10/02)
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