- Cycloaddition reaction of tert-butyl isocyanate and a tellurium diimide dimer: Extended helical structure of the ureato telluroxide {[OC(μ-NBu(t))2TeO]2(thf)}∞
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The reaction of Bu(t)NTe(μ-NBu(t))2TeNBu(t) with Bu(t)NCO in a 1:4 molar ratio in thf produces N,N'-bis(tert-butyl)ureato telluroxide dimers [OC(μ-NBu(t))2TeO]2, which form an extended helical network via weak >C=O···Te interactions.
- Schatte,Chivers,Jaska,Sandblom
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Read Online
- Method of producing N,N'-ditertiary butyl dicarbodiimide by thiourea method
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The invention belongs to the technical field of organic synthesis, and in particular relates to a method of producing N,N'-ditertiary butyl dicarbodiimide by a thiourea method. The method comprises the following steps: first, synthesizing N,N'-ditertiary butyl thiourea in a water medium by using tert-butylamine and carbon disulfide; carrying out suction filtration on the N,N'-ditertiary butyl thiourea, drying, carrying out primary oxidization, successively adding the mixture, caustic soda flakes, a solvent and a catalyst into a reaction kettle, heating the mixture to 60-65 DEG C, adding an oxidizing agent to react for 2 hours at 60-65 DEG C, leaving the product to stand for 20-25 minutes, and abandoning a lower water phase; carrying out secondary oxidizing reaction, dropwise adding quantitative oxidizing agent and catalyst, and carrying out a reaction for 1 hour at 65 DEG C; and adding alkali to neutralize, washing with water, separating a water layer, distilling the solvent out, and carrying out rectification at a reduced pressure to obtain N,N'-ditertiary butyl dicarbodiimide. The method of producing N,N'-ditertiary butyl dicarbodiimide by the thiourea method is mild in reactioncondition, high in yield, high in purity and simple in post-treatment, and process water can be recycled.
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Paragraph 0026-0040
(2019/03/08)
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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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p. 11753 - 11762
(2019/12/02)
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- 1,1′-Dicarbodiimidoferrocenes: Synthesis, Characterization, and Group IV 1,1′-Bisguanidinateferrocene Complexes
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We report the two-step one-pot preparation of a series of bulky substituted 1,1′-dicarbodiimidoferrocene proligands. In solution the compounds achieve equilibrium with the corresponding 2,4-diimino-1,3-azetidine products which exhibit distinct spectroscopic and electrochemical features. Metalation of the carbodiimides with M(NMe2)4 (M = Zr, Hf) leads to fluxional six-coordinate compounds that exhibit intermediate Bailar twist features in solution and in the solid state. Coordination of the 2,4-diimino-1,3-diazetidines to Zr(NMe2)4 results in a metal-mediated carbodiimide metathesis into two zirconium guanidinate complexes, which can be rationalized by a two-step reaction mechanism.
- Palomero, Orhi Esarte,Jones, Richard A.
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p. 2689 - 2698
(2019/07/04)
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- Synthesis of 2-aminobenzoxazoles and 3-aminobenzoxazines via palladium-catalyzed aerobic oxidation of o -aminophenols with isocyanides
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A Pd-catalyzed aerobic oxidation of o-aminophenols and isocyanides for the synthesis of 2-aminobenzoxazoles and 3-aminobenzoxazines has been achieved in an air atmosphere. The procedure constructs 2-aminobenzoxazoles and 3-aminobenzoxazines with moderate to excellent yields and a broad substrate scope. Apart from experimental simplicity, this methodology has the advantages of mild reaction conditions and easily accessible starting materials. Furthermore, the utility of this method has also been successfully applied to the synthesis of other types of useful nitrogen heterocycles.
- Liu, Bifu,Yin, Meizhou,Gao, Hanling,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 3009 - 3020
(2013/06/26)
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- Syntheses and15N NMR Spectra of Iminodiaziridines - Ring-Expansions of 1-Aryl-3-iminodiaziridines to 1H- and 3aH-Benzimidazoles, 2H-Indazoles, and 5H-Dibenzo[d,f] [1,3]diazepines
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Iminodiaziridines are synthesized, by (i) 1,3-dehydrochlorination with potassium, teri-butoxide of N-chloroguanidines, generated in situ from. N,N′,N″-substituted guanidines with tert-butyl hypochlorite, and (ii) base-mediated 1,3-elimination of sulfuric acid from N,N',N″- substituted hydroxyguanidine O-sulfonic acids. At elevated temperatures, (alkylimino)diaziridines undergo valence isomerization by 1,3shift, [2+1] cycloelimination to afford isocyanides and diazenes, and ring-opening elimination to yield alkylideneguanidines. N′-Aryl-N-hydroxyguanidine O-sulfonic acids furnish (N-arylimino)diaziridines, but no 1-aryl-3- iminodiaziridines, instead giving rearranged isomere. Precursors containing perdeuterated feri-butyl groups give rearranged products that show complete scrambling. This indicates that l-aryl-3iminodiaziridines are intermediates that undergo very rapid I degenerate valence isomerization. Provided that the ortho aryl positions are substituted, high yields of (arylimino)diaziridines are obtained, along with 2-imino-2,3-dihydro-3aHbenzimidazoles, Otherwise, 2-amino-lH-benzimidazoles and strongly fluorescent 3-amino-2H-indazoles, originating from rearrangements of the elusive l-aryl-3-iminodiaziridines, predominate. N',N″-Diaryl-N-hydroxyguanidine O-sulfonic acids give only rearranged products: a 2-amino-1H-benzimidazole and a 6-amino-5H-dibenzo[d,f][1. 3]diazepine if aryl = phenyl, or a 2-imino-2,3-dihydro-3aH-benzimidazole if aryl = mesityl. 3aH-Benzimidazoles slowly dimerize through Diels-Alder reactions. 15N NMR signals were assigned, to the syn and anti ring nitrogen atoms of iminodiaziridines with the help of a combination of homonuclear NOE and HNHMBC or HN-gHMBC experiments.
- Quast, Helmut,Ross, Karl-Heinz,Philipp, Gottfried,Hagedorn, Manfred,Hahn, Harald,Banert, Klaus
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experimental part
p. 3940 - 3952
(2010/03/01)
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- Synthetic studies toward aryl-(4-aryl-4H-[1,2,4]triazole-3-yl)-amine from 1,3-diarylthiourea as urea mimetics
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A thiophile-promoted synthesis of disubstituted 4H-[1,2,4]triazole-3-yl- amines as urea mimetics from the corresponding 1,3-disubstituted thioureas has been studied, and the scope and limitations of this reaction are presented. The reaction proceeds through the formation of a carbodiimide, followed by a sequential addition-dehydration with acyl hydrazides. 1,3-Branched dialkylthioureas result in the formation of the corresponding ureas. The electronic and steric effects of the substitution on the phenyl rings of the 1,3-diarylthioureas play an important role in the formation of the intermediary carbodiimde and the direction of the subsequent ring closure of the N-acyl hydrazide adduct.
- Natarajan, Amarnath,Guo, Yuhong,Arthanari, Haribabu,Wagner, Gerhard,Halperin, Jose A.,Chorev, Michael
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p. 6362 - 6368
(2007/10/03)
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- Oxo and imido/imido exchange and C-H activation reactions based on pentamethylcylopentadienyl imido tantalum complexes
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Reactions of [TaCp*Cl4] with two, three and four equivalents of LiNHtBu give the halo- and amido-imido complexes [TaCp*Cl2(NtBu)] (1a), [TaCp*Cl(NtBu)(NHtBu)] (2) and [TaCp*(NtBu)(NHtBu)2] (3), respectively. The related complex [TaCp*Cl2{N(2,6-Me2C6H3)}] (1b) is prepared by a similar reaction using two equivalents of Li[NH(2,6-Me2C6H3)]. Complex 3 can be transformed into 2 and further into 1a by reaction with SiClMe3. Complex 1a reacts with CNtBu to give the 18-electron adduct [TaCp*Cl2(NtBu)(CNtBu)] (4) whereas addition of excess CN(2,6-Me2C6H3) results in reductive elimination of the carbodiimide tBuN=C=N(2,6-Me2C6H3) (5) to give [TaCp*Cl2{CN(2,6-Me2C6H 3)}3]. However complex 1b does not react with any of the isocyanide ligands. Both complexes 1a and 1b react with PhCHO undergoing imido/oxo exchange to give the imines PhCH=NR (R=tBu, 2,6-Me2C6H3 (6)) and dimeric [TaCp*Cl2(O)]2 or trimeric [(TaCp*Cl)3(μ2-Cl)(μ2-O) 3(μ3-O)] oxo-complexes, whereas only 1a reacts with CO2, PhCH=NR′ (R′=Ph, Me) and (2,6-Me2C6H3)N=C=NtBu producing tBuN=CO, PhCH=NtBu and tBuN=C=NtBu, respectively and the corresponding oxo or imido tantalum derivative. None of the complexes reacts with CO or NCR (R=Me, Ph). The complex [TaCp*Me(NtBu)(NHtBu)] activates C-H bonds when heated in benzene and toluene affording [TaCp*Ph(NtBu)(NHtBu)] (7) and a mixture of [TaCp*(m-MeC6H4)(NtBu)(NHtBu)] 8a and [TaCp*(p-MeC6H4)(NtBu)(NHtBu)] (8b). All of the reported organic compounds and tantalum complexes were characterized by 1H- and 13C-NMR spectroscopy.
- Royo, Pascual,Sánchez-Nieves, Javier
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- 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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- N,N-Dialkylcarbodiimide synthesis by palladium-catalysed coupling of amines with isonitriles
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Catalytic condensation of amines and isonitriles can be accomplished efficiently at 100°C using a palladium complex catalyst, oxygen, and iodine to give N,N-dialkylcarbodiimides.
- Pri-Bar, Ilan,Schwartz, Jeffrey
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p. 347 - 348
(2007/10/03)
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- A new and efficient preparation of carbodiimides from ureas using dimethylphosgeniminium chloride as a dehydrating agent
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Dimethylphosgeniminium chloride was used as dehydrating agent for the preparation of carbodiimides from ureas.
- Schlama,Gouverneur,Mioskowski
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p. 7047 - 7048
(2007/10/03)
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- Metathesis and reduction reactions of nitroso compounds with metal carbenes and metal carbonyls
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Reaction of nitroso compounds with metal-carbene complexes and metal carbonyls has been investigated.These reactions lead to reduction of the nitroso compounds, primarily to the corresponding azo- and azoxy compounds.Metal-nitrene complexes have been proposed as intermediates in these reactions.These intermediates couple rapidly with the unreacted nitroso compound, or enter into nitrene-like reactions with external or internal trapping agents.Reaction of metal carbonyls with nitrosoarenes and photolysis has been found to be an effective method for the reduction of nitrosoarenes to azoxyarenes, with few problems resulting from overreduction to amines or azo compounds.
- Herndon, James W.,McMullen, Leonard A.
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- Preparation of Carbodiimides Using Phase-Transfer Catalysis
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A new method is described for the preparation of carbodiimides by dehydration of ureas with arenesulfonyl chlorides under solid-liquid phase-transfer catalytic (PTC) conditions using solid potassium carbonate as a base and a lipophilic quaternary ammonium salt as a catalyst.The method is generally applicable for the synthesis of disubstituted carbodiimides, but is especially useful for unsymmetrically substituted carbodiimides.The basic carbodiimides prepared were identified in the form of the more stable, crystalline quaternary salts.
- Jaszay, Zsuzsa M.,Petnehazy, Imre,Toeke, Laszlo,Szajani, Bela
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p. 520 - 523
(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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- Reaction of Electrochemically Generated Triphenylphosphine Radical Cation with Amides and Ureas
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Constant-current electrolysis of triphenylphosphine in dichloromethane in the presence of primary amides and N,N'-disubstituted ureas resulted in the formation of nitriles and carbodiimides, respectively.Dehydrosulfurization of thiobenzamide and N,N'-dicyclohexylthiourea was also effected by electrlysis under the same conditions, but probably through mechanisms different from those of dehydration of the corresponding amide and urea.Keywords-constant-current electrolysis; triphenylphosphine; primary amide; N,N'-disubstituted urea; nitrile; carbodiimide
- Ohmori, Hidenobu,Sakai, Kiyoshi,Nagai, Noriko,Mizuki, Yasuyuki,Masui, Masaichiro
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p. 373 - 376
(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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- Synthesis and Decomposition of Functionalized Diaziridinimines
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The conversion of guanidines into diaziridinimines on treatment with t-BuOCl and t-BuOK can be applied to the synthesis of sulfonyl-, phosphoryl-, and cyano-substituted derivatives bearing two additional tert-butyl groups.Carbethoxy- and benzoyl-substituted guanidines give N-carbonyl-substituted diaziridinimines only as elusive intermediates which rearrange into 5-imino-Δ2-1,3,4-oxadiazolines.Other decomposition pathways observed are (i) rearrangement of sulfonylimino- and phosphorylimino-substituted diaziridines into hydrazine derivatives and (ii) cheletropic decomposition of N-cyano-substituted diaziridinimines into carbodiimides and cyanonitrene.
- L'abbe, Gerrit,Verbruggen, Andre,Minami, Toru,Toppet, Suzanne
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p. 4478 - 4481
(2007/10/02)
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