- MIGRATION REVERSIBLE DE PHOSPHORYLE S-P N-P CONTROLEE PAR TRANSFERT DE PROTON, MODELE D'ACTIVATION PAR PHOSPHORYLATION
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This work describes the reversible C-addition of a sterically hindered-P thiophosphoric ester to a carbodiimide, as a model of activated biotin.The formed intermediate, is found to be in equilibrium with the corresponding N-phosphorylated thiourea.The entire system is controlled by proton transfer and reversible.
- Blonski, C.,Gasc, M. B.,Klaebe, A.,Perie, J. J.
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Read Online
- Stimuli-Responsive Frustrated Lewis-Pair-Type Reactivity of a Tungsten Iminoazaphosphiridine Complex
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Reactions of 3-imino-azaphosphiridine complexes 1 a,b with carbodiimides 2 a,b, isocyanates 3 a,b, and carbon dioxide are described. Whereas exchange of the carbodiimide unit occurs in the first case, an overall ring expansion takes place with phenyl isocyanate (3 a) and carbon dioxide to yield complexes 4 and 5 bearing novel 1,3,5-oxazaphospholane ligands; the isopropyl derivative 3 b did not react under these conditions. DFT calculations provide insight into the pathway of the reaction with carbon dioxide with model complex 1 c, revealing effects of initial non-covalent interactions with the substrate onto the ring bonding, thus triggering an initially masked frustrated Lewis-pair-type behavior.
- Villalba Franco, José Manuel,Schnakenburg, Gregor,Sasamori, Takahiro,Espinosa Ferao, Arturo,Streubel, Rainer
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Read Online
- Method for preparing N,N'-dicyclohexylcarbodiimide by using co-reactor
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The invention discloses a method for preparing N,N'-dicyclohexylcarbodiimide by using a co-reactor. The method comprises the steps of maintaining an aqueous solution of cyclohexylamine in a strong alkaline environment in the same reactor, adding carbon disulfide into the same reactor, and adding sodium hypochlorite for oxidation to obtain N,N'-dicyclohexylcarbodiimide. According to the method, thetechnological process is simplified through the co-reactor reaction, generation of highly toxic and harmful gas is avoided, the safety risk of production is reduced, and then the purpose of environment-friendly and safe production is achieved.
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Paragraph 0043-0046
(2021/03/30)
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- Method for producing N,N'-dicyclohexyl carbodiimide
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The invention discloses a preparation method of N,N'-dicyclohexyl carbodiimide. The method comprises the following steps: taking dicyclohexyl urea (DCU) and trichloromethyl carbonate (BTC) as raw materials, dissolving dicyclohexyl urea (DCU) in a solvent, uniformly stirring, cooling, adding trichloromethyl carbonate and a catalyst loaded on a molecular sieve, carrying out heat preservation reflux, cooling, adjusting the pH value to 8-9 by using alkali, filtering the reaction liquid, evaporating out the solvent, and carrying out reduced pressure distillation to obtain the product namely N,N'-dicyclohexyl carbodiimide. According to the present invention, the problems of strong odor, strong toxicity and heavy environmental pollution of the traditional process are fundamentally eliminated, and the method has characteristics of high safety coefficient, partial catalyst recycling, high catalysis efficiency, partial raw material recycling, less three wastes, high purity and high yield, and is suitable for industrial production.
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Paragraph 0013; 0027-0045
(2021/05/08)
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- Microwave-assisted method for synthesizing N,N'-dicyclohexyl carbodiimide
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The invention relates to the technical field of organic synthesis, in particular to a method for synthesizing N,N'-dicyclohexyl carbodiimide through a microwave-assisted method. The method comprises the following steps: dissolving N,N'-dicyclohexyl urea in a solvent under microwave radiation, adding an oxidant and a catalyst loaded on a molecular sieve, and carrying out heat preservation reflux; adding a phase transfer catalyst, adjusting the pH value, and carrying out alkaline hydrolysis reaction; filtering, separating liquid, evaporating out the solvent, and carrying out reduced pressure distillation to obtain N,N'-dicyclohexyl carbodiimide. The catalyst loaded on the molecular sieve is large in specific surface area and high in catalytic efficiency; a microwave-assisted method is adopted, and a phase transfer catalyst is added, so that the problems of difficult two-phase reaction and incomplete reaction in the traditional process are solved, the reaction conversion rate is greatly improved, the reaction time is shortened, and the product has the characteristics of high purity and yield.
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Paragraph 0032-0051
(2021/04/17)
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- Preparation method of dicyclohexylcarbodiimide
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The invention relates to a method for preparing dicyclohexylcarbodiimide by using recycled dicyclohexylurea, and the method comprises the following steps: adding the recycled dicyclohexylurea into a mixed system composed of water and an organic solvent, stirring, washing, filtering, and drying; uniformly stirring the dried dicyclohexylurea and an organic solvent, adding oxalyl chloride at a certain temperature for reaction, keeping the temperature for 0.5 h after dripping is finished, dripping reaction liquid into an aqueous solution of sodium hydroxide, filtering, standing filtrate for layering to obtain an organic phase, concentrating the organic phase, and performing reduced pressure distillation to obtain the dicyclohexylcarbodiimide. According to the method, DCU generated after DCC isused is regenerated into DCC, cyclic application is achieved, the technological method has the advantages of being safe, reliable and high in recovery rate, and industrial production can be achieved.
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Paragraph 0018-0023
(2020/04/02)
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- Method for preparing dicyclohexylcarbodiimide by using vilsmeier reagent
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The invention discloses a method for preparing dicyclohexylcarbodiimide by using a vilsmeier reagent. The method comprises the following steps: preparing a vilsmeier reagent by using N, N-dimethylformamide (DMF) and thionyl chloride (SOCl2), reacting the vilsmeier reagent with dicyclohexylurea (DCU), and carrying out aftertreatment to obtain the dicyclohexylcarbodiimide. According to the method, the vilsmeier reagent is adopted, the reaction can be carried out under mild conditions, the process is safe and stable, and the method is suitable for industrial large-scale production.
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Paragraph 0015; 0021-0029
(2020/12/30)
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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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- Method for synthesizing N, N'-dicyclohexylcarbodiimide through hydrogen peroxide serving as oxidizing agent
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The invention relates to a method for synthesizing N, N'-dicyclohexylcarbodiimide through hydrogen peroxide serving as an oxidizing agent. The method comprises the following steps: mixing N, N'-dicyclohexyl thiocarbamide and a solvent, slowly adding a catalyst, dropwise adding hydrogen peroxide at 15 to 25 DEG C to perform oxidation reaction, performing heat preservation for 1.5 h after dropwise adding is accomplished, then performing suction filtration at 15 DEG C, and performing decoloration and reduced pressure distillation, so as to obtain the N, N'-dicyclohexylcarbodiimide. The method hasthe advantages that the oxidizing agent hydrogen peroxide is adopted to ensure that reaction is more complete, the content of by-products N, N'-dicyclohexylurea and cyclohexyl isothiocyanate is controlled to be lower than 100 ppm, the product quality is improved, and the problem that effluent brine is difficult to treat is solved; a reaction system is optimized, a triethylamine catalyst is adopted to ensure that the reaction is performed in a homogeneous reaction system, the reaction yield is improved, the DCC yield is improved to greater than 93.5 percent, and the reaction is easy to control; and the material utilization is improved, the amount of waste is reduced, the investment in environmental protection is reduced, and the production cost is reduced.
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Paragraph 0020-0021; 0022-0023; 0024-0025; 0026-0027
(2019/02/26)
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- Preparation method of dicyclohexylcarbodiimide
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The invention belongs to the technical field of fine chemical engineering and in particular relates to a preparation method of dicyclohexylcarbodiimide. The preparation method comprises the followingsteps: dissolving chloroacetyl chloride in a solvent to obtain a solution A; stirring dicyclohexylurea, a catalyst and a solvent uniformly to obtain a solution B; dropwise adding the solution A into the solution B at a certain temperature; then carrying out an insulating reaction; after the reaction, adding a pH regulator to regulate the solution to be neutral; carrying out suction filtration on the reaction solution; distilling the filtrate at constant pressure to remove the solvent; and then carrying out distillation at a reduced pressure to obtain dicyclohexylcarbodiimide. The preparation method of dicyclohexylcarbodiimide is simple in process, the reaction stability and the product yield are improved greatly, dicyclohexylcarbodiimide can be produced industrially on a large scale, and the preparation method has the advantages of being simple and feasible and simple to operate.
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Paragraph 0021-0032
(2019/02/06)
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- The use of oxygen as oxidizing agent a synthetic N, N' - dicyclohexyl carbodiimide method (by machine translation)
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The use of oxygen as oxidizing agent a synthetic N, N'- dicyclohexyl carbodiimide method, steps are as follows: in the high-pressure reaction kettle adding N, N' - b ring has been thiourea, normal hexane as solvent, adding V2 O5 - P2 O5 Catalyst, access a sufficient amount of oxygen, to control the pressure and the temperature of the oxidation reaction of the 2 - 3 h, then cooling down to 15 °C filtering, by decolorization, distilled under reduced pressure to obtain the DCC. The invention using oxygen as the oxidant, the reaction selectivity is high, low-risk, at the same time greatly reducing the amount of waste water and is easy to process, the traditional process solves the problem waste water disaster; optimizes reaction system, the use of V2 O5 - P2 O5 Catalyst, the reaction in a homogeneous phase in the reaction system, it is easy to control, thus increasing the reaction yield, DCC oxidation yield of 93% or more, the purity of 99.2% above; process step green environmental protection, reduced for environmental protection, the production cost is reduced. (by machine translation)
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Paragraph 0018; 0019; 0020; 0021; 0022; 0023; 0024; 0025
(2019/04/06)
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- Multicomponent Approach to Libraries of Substituted Dihydroorotic Acid Amides
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A process featuring a sequential multicomponent reaction followed by a regioselective postcyclization strategy was implemented for the facile synthesis of N,N′-disubstituted dihydroorotic acid amides under mild conditions. We obtained, for the first time, a library of 29 derivatives, encompassing 19 Nα-substituted-N4-dihydroorotyl-4-aminophenylalanine derivatives, a key residue of gonadotropin-releasing hormone antagonist Degarelix. The corresponding products were prepared from easily accessible starting materials in good to excellent yields with broad substrate scope.
- Bellucci, Maria Cristina,Sacchetti, Alessandro,Volonterio, Alessandro
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supporting information
p. 705 - 715
(2019/10/02)
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- Oxidation method for N,N'-dicyclohexylthiourea
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The invention discloses an oxidation method for N,N'-dicyclohexylthiourea. The method comprises the following steps: adding N,N'-dicyclohexylthiourea, benzene and water into an autoclave, adding caustic soda flakes and a catalyst, sealing the autoclave, performing leakage test, replacing air in the autoclave with oxygen, performing stirring, introducing oxygen, and performing a heating reaction; performing hot filtration after the reaction is completed, and performing liquid separation; and adding sodium sulfide to wash the obtained organic phase, washing the organic phase with alkaline watertwo times, distilling off the solvent benzene, and performing reduced pressure distillation to obtain N,N'-dicyclohexylcarbodiimide. Compared with the prior art, the method has the following advantages: 1. the N,N'-dicyclohexylthiourea is directly oxidized by oxygen, so the generation of wastewater and waste salts is reduced, and the production cost is reduced; and 2, the oxidant during the oxidation of the N,N'-dicyclohexylthiourea is a clean raw material, and is easy to obtain, and the complex product is simple.
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Paragraph 0013-0016
(2020/04/02)
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- Preparation method of curcumin nicotinate
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The invention discloses a preparation method of curcumin nicotinate. Niacin and curcumin are used as reactants, DAMP (4-dimethylaminopyridine) is used as a catalyst, a dehydrating agent and a reactionsolvent are added, the mixture reacts, and the curcumin nicotinate is obtained. A turmeric extract, namely, the curcumin, is used as an initial material and subjected to catalytic esterification to react with niacin in the presence of the dehydrating agent DCC or EDC by use of advantages of a catalytic acylation reaction of the efficient catalyst DAMP, the curcumin nicotinate is prepared throughone-step esterification, and the total yield is 89.4%. The route is mild in reaction condition, convenient in aftertreatment, higher in yield and suitable for industrial production.
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Paragraph 0022; 0030; 0031
(2018/09/11)
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- Preparation method to recycle pyribenzoxim byproduct dicyclohexylurea
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The invention discloses a preparation method to recycle pyribenzoxim byproduct dicyclohexylurea and belongs to the field of agricultural chemistry. The byproduct N,N'-dicyclohexylurea is used as a rawmaterial; N,N'-dicyclohexylurea and organic phosphorus catalyst are heated to 140-160 for reacting; the temperature is then lowered to 60-80 DEG C for reacting; after reacting, the catalyst is recycled by filtering, and filtrate is distilled under reduced pressure; distillate at 125-140 DEG C (6-8 mmHg) is collected and cooled to obtain white solid, N,N'-dicyclohexylcarbodiimide; the highest yield reaches 88.2%, and purity reaches 98.4%. The preparation method is efficient, environmentally friendly, sustainable, and suitable for industrial production; the preparation method has the advantagesof good energy efficiency, low consumption, lower pollutant emission and the like, allows a preparation technique of recycling byproducts of pyribenzoxim production process to be implemented, and meets the green manufacturing principle.
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Paragraph 0011; 0022-0029
(2019/01/14)
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- Mechanistic Insight Facilitates Discovery of a Mild and Efficient Copper-Catalyzed Dehydration of Primary Amides to Nitriles Using Hydrosilanes
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Metal-catalyzed silylative dehydration of primary amides is an economical approach to the synthesis of nitriles. We report a copper-hydride(CuH)-catalyzed process that avoids a typically challenging 1,2-siloxane elimination step, thereby dramatically increasing the rate of the overall transformation relative to alternative metal-catalyzed systems. This new reaction proceeds at ambient temperature, tolerates a variety of metal-, acid-, or base-sensitive functional groups, and can be performed using a simple ligand, inexpensive siloxanes, and low catalyst loading.
- Liu, Richard Y.,Bae, Minwoo,Buchwald, Stephen L.
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supporting information
p. 1627 - 1631
(2018/02/17)
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- Dehydration of an Insoluble Urea Byproduct Enables the Condensation of DCC and Malonic Acid in Flow
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A procedure for the preparation of N,N′-dicyclohexylbarbituric acid from DCC and malonic acid is described. Addition of phosphorus oxychloride to the reaction mixture facilitates dehydration of the insoluble byproduct N,N′-dicyclohexyl urea, enabling operation in continuous flow. A development approach based on in situ monitoring of batch reactions was used, which supported screening and determination of reaction conditions at small scale prior to scaleup in flow. Additional mechanistic understanding and control of impurity formation are presented.
- O'Brien, Alexander G.,Ricci, Eric M.,Journet, Michel
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p. 399 - 402
(2018/03/22)
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- EXOSOME-CONJUGATED QUANTUM DOT NANOPARTICLES AND METHODS OF DETECTING EXOSOMES AND CANCER USING SAME
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The present disclosure relates to a plurality of quantum dot nanoparticles conjugated to ligands, and in particular a plurality of quantum dot nanoparticles wherein each nanoparticle is conjugated to an exosome-specific binding ligand. The present disclosure also relates to methods of making such a plurality of conjugated quantum dot nanoparticles, methods of detecting exosomes using such a plurality of conjugated quantum dot nanoparticles and methods of detecting exosomes using such a plurality of conjugated quantum dot nanoparticles.
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- A method of manufacturing a carbodiimide compound
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PROBLEM TO BE SOLVED: To provide a novel method that can efficiently produce a carbodiimide compound without using substances that are harmful, hazardous, expensive, or difficult to obtain.SOLUTION: The method of producing a carbodiimide compound includes converting a thiourea compound having a specific structure to a carbodiimide compound having a specific structure in the presence of at least one of an iron compound and a molybdenum compound.
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Paragraph 0056-0059; 0062; 0063
(2018/03/02)
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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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- Preparation method of carbodiimide
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The invention relates to a preparation method of carbodiimide. The preparation method includes: taking dicychlohexylurea (DCU) and bis(trichloromethyl) carbonate (BTC) as raw materials; adopting a composite catalyst for preparing to obtain dicyclohexylcarbodiimide. The preparation method is characterized in that the composite catalyst is a compound mixture of a rare earth compound and ionic liquid.
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Paragraph 0027; 0028
(2016/11/07)
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- A recycled waste water preparation N, N '-dicyclohexylcarbodiimide method for the production of
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The invention discloses a production method for preparing N,N'-dicyclohexylcarbodiimide (DCC) by recycling wastewater, belonging to the technical field of organic compound synthesis. The method solves the problem of unmanageable brine sewage at present. The method comprises the following steps: washing N,N'-dicyclohexylurea (DCU) generated after using DCC with water to remove impurities, reacting with an oxidizer in an organic solvent, dropwisely adding the reaction solution into an alkali water solution to carry out neutralization reaction, filtering the neutralization reaction product, standing to stratify, and carrying out distillation separation on the organic layer to obtain the DCC product, wherein the distilled solvent is directly recovered; and filtering out inorganic salts from the water layer to obtain recovered water for preparing the alkali solution. The DCU generated after using the DCC is recovered to obtain the DCC; and the generated brine wastewater is recycled, thereby reducing the discharge of the brine sewage and greatly lowering the brine sewage treatment.
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Paragraph 0038-0043
(2017/03/17)
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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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p. 1974 - 1977
(2015/04/27)
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- QUINAZOLINE-2,4-DIONE DERIVATIVES
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The invention relates to antibacterial compounds of formula (I), wherein R1 is H, halogen, (C1-C3)alkyl or (C1-C3)alkoxy; R2 is H, halogen, (C1-C3)alkyl, (C1-C3)alkoxy or pyrrolidin-1-yl; R3 is H, halogen, (C1-C3)alkyl, (C1-C3)alkoxy, vinyl or 2-methoxycarbonyvinyl or R2 and R3 together with the two carbon atoms which bear them form a phenyl ring; R4 is H, halogen, (C1-C3)alkyl or (C1-C3)alkoxy; and R5 is H, (C1-C3)alkyl or cyclopropyl, or R4 and R5 form together a —CH2CH2CH2— group; A is the divalent group —CH2—, —CH2CH2—, #—CH(OH)CH2—*, #—CH2N(R6)—* and —CH2NHCH2—, wherein # indicates the point of attachment to the optionally substituted (quinazoline-2,4-dione-3-yl)methyl residue and * represents the point of attachment to the substituted (oxazolidinon-4-yl)methyl residue; R6 is H or acetyl; Y is CH or N; and Q is O or S; and salts of such compounds.
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- Dehydrogenative desulfurization of thiourea derivatives to give carbodiimides, using hydrosilane and an iron complex
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Dehydrogenative desulfurization of thiourea derivatives (RNHC(S)NHR′) has been achieved, to give carbodiimides (RNCNR′), in the reaction with hydrosilane and (η5-C5H5)Fe(CO) 2Me. The obtained carbodiimide reacted with (η5-C 5H5)Fe(CO)(SiR3) formed in the reaction to give an N-silylated η2-amidino iron complex, which was isolated and then characterized by X-ray analysis.
- Hayasaka, Kazumasa,Fukumoto, Kozo,Nakazawa, Hiroshi
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p. 10271 - 10276
(2013/07/26)
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- HEPATITIS C VIRUS NS3 PROTEASE INHIBITORS
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The present invention relates to macrocyclic compounds of Formula (I) that are useful as inhibitors of the hepatitis C virus (HCV) NS3 protease, their synthesis, and their use for treating or preventing HCV infections.
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- Synthesis and X-ray crystal structures of imido and ureato derivatives of titanium(iv) phthalocyanine and their application in the catalytic formation of carbodiimides by metathesis from isocyanates
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The imido titanium phthalocyanine complex [PcTi(NDip)] (Dip = 2,6-diisopropylphenyl) 2a was synthesized from [PcTiO] 1 and one eq. of DipNCO. Due to the steric demand of the Dip group, addition of another isocyanate molecule to the TiN functionality of 2a does not occur even at high molar ratios of DipNCO. However, 1 reacts with 2 eq. of arylisocyanates containing sterically less demanding aryl groups producing N,N′- diarylureatotitanium(iv)phthalocyanines [PcTi{κ2-(NR)C(O) (N′R)}] (R = p-tolyl (Tol) 3a or mesityl (Mes) 3b). The N,N′ coordination (III) of the ureato ligand in 3a and 3b was proven by a single set of resonances for the aryl groups in their 1H-NMR spectra. An N,O coordination (IV) can therefore be excluded. This is also confirmed by the X-ray crystal structure of 3a. Upon heating [PcTiO] and an excess of aryl isocyanates for 6 days, a steady evolution of CO2 was observed and a white precipitate, identified as the corresponding diarylcarbodiimides (V), could be isolated. Therefore this reaction was applied in the metathetic conversion of two isocyanate molecules into diarylcarbodiimides (V) and CO2. Additionally, imido titanium Pc's 2b (R = tBu) and 2c (R = Mes) were prepared by a more general synthetic strategy, reacting the potassium salt of the ligand PcK2 with appropriate imido titanium precursors.
- Darwish, Wael,Seikel, Elisabeth,Kaesmarker, Ralf,Harms, Klaus,Sundermeyer, Joerg
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experimental part
p. 1787 - 1794
(2011/05/07)
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- A New synthetic protocol for the preparation of carbodiimides using a hypervalent iodine(III) reagent
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A new, simple, and efficient preparation of symmetrical and unsymmetrical carbodiimides from the corresponding thioureas via dehydrosulfurization using a hypervalent iodine(III) reagent is described. The oxidation afforded carbodiimides in excellent yields and high selectivity. A possible mechanism for the transformation is proposed. Georg Thieme Verlag Stuttgart New York.
- Zhu, Chenjie,Xu, Dan,Wei, Yunyang
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supporting information; experimental part
p. 711 - 714
(2011/04/24)
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- O-Iodoxybenzoic acid mediated oxidative desulfurization of 1,3-disubstituted thioureas to carbodiimides
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An efficient and mild oxidative desulfurization procedure using o-iodoxybenzoic acid has been developed for the synthesis of carbodiimides starting from easily synthesizable 1,3-disubstituted thioureas.
- Chaudhari, Pramod S.,Dangate, Prasad S.,Akamanchi, Krishnacharya G.
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supporting information; experimental part
p. 3065 - 3067
(2011/02/25)
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- Catalytic conversion of isocyanates to carbodiimides by cyclopentadienyl manganese tricarbonyl and cyclopentadienyl iron dicarbonyl dimer
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Isocyanates are catalytically converted to the corresponding carbodiimides in the presence of low valent transition metal complexes. The best conversions and yields were accomplished using [(C5R5)Fe(CO)2]2 (R = H or Me) or MeCpMn(CO)3 as catalysts.
- Rahman, A.K. Fazlur,Nicholas, Kenneth M.
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p. 6002 - 6004
(2008/02/10)
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- Gold metal-catalyzed reactions of isocyanides with primary amines and oxygen: Analogies with reactions of isocyanides in transition metal complexes
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Despite its generally poor catalytic properties, bulk gold metal is observed to catalyze reactions of isocyanides (C≡N-R) with primary amines (H2N-R′) and O2 to give carbodiimides (R-N=C=N-R′) at room temperature and above. Detailed infrared reflection absorption spectroscopic (IRRAS) and kinetic studies show that the reaction occurs by initial η1-adsorption of the isocyanide on the Au surface, which activates the isocyanide to attack by the amine. This attack is the rate-determining step in the catalytic cycle and has characteristics very similar to those of amine reactions with coordinated isocyanides in transition metal complexes. However, the metallic Au surface provides a pathway involving O2 to give the carbodiimide product whereas homogeneous metal ion catalysts give formamidines [HC(=NR)(NHR′)].
- Lazar, Mihaela,Angelici, Robert J.
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p. 10613 - 10620
(2007/10/03)
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- METHOD FOR THE PRODUCTION OF SUBSTANCES COMPRISING CARBODIIMIDE GROUPS
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The invention relates to a method for the production of substances comprising carbodiimide groups.
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Page/Page column 4; 5
(2008/06/13)
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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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- 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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- Selective and Efficient Syntheses of Perhydro-1,3,5-triazine-2,4,6-triones and Carbodiimides from Isocyanates Using ZP(MeNCH2CH2)3N Catalysts
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With concentrations as low as 0.0033 mol percent ZP(MeNCH2CH2)3N (Z = lone pair, 1) isocyanates are catalytically trimerized to perhydro-1,3,5-triazine-2,4,6-triones (isocyanurates) at room temperature.This reaction proceeds readily in the presence or absence of solvent, and the catalyst can be recycled at least six times without detectable degradation.Though not as potent a catalyst as 1, the molecule in which Z = NPh (3) also facilitates this reaction, and evidence is adduced that the catalytically active species is the adduct 3*ArNCO (6).In contrast, Ch=P(MeNCH2CH2)3N (Ch = O, 4; Ch = S, 5) selectively catalyze the transformation of isocyanates to carbodiimides and do so more efficiently than their acyclic analogues O=P(NMe2)3 and (MeO)2P(S)Ph, respectively.The crystal structure of 4 is reported for the first time, and details of the crystal structure of I reported earlier by us in preliminary form are presented.Both structures support the hypothesis that P-Nax transannulation plays a lead role in the catalytic activities of 1 and 3 - 5.
- Tang, Jiansheng,Mohan, Thyagarajan,Verkade, John G.
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p. 4931 - 4938
(2007/10/02)
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- Selective Formation of Five-Membered Heterocyclic Products by Anodic Oxidation of Alkyl Isothiocyanates (RNCS) in Dichloromethane and Their Thermal Isomerization and Decomposition
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Anodic oxidation of primary and secondary alkyl isothiocyanates (RNCS) in dichloromethane yielded two isomers of five-membered heterocyclic products, 4-alkyl-5-(alkylimino)-1,2,4-dithiazolidine-3-one 2 and 2,4-dialkyl-5-oxo-1,2,4-thiadiazolidine-3-thione 3.Their relative ratio was found to be depedent on the length or bulkiness of the alkyl group in RCNS.Isomer 2 was favorable for R = Me and Et and exclusive for R = n-Pr, n-Bu, and cyclohexyl.Upon GLC injection (at 150-200 deg C), compounds of type 2 isomerized completely to 3 (when R = Me, Et), mostly to 3 and partially decomposed to RN=C=NR (11) (when R = n-Pr, n-Bu), and exclusively decomposed to 11 for R = cyclohexyl.Tertiary RNCS did not yield cyclic products but instead underwent chlorination to substitute a hydrogen (or "NCS" group) by chlorine.Plausible mechanistic schemes are suggested and discussed.
- Becker, James Y.,Yatziv, Shimon
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p. 1744 - 1748
(2007/10/02)
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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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- DI-2-PYRIDYL SULFITE. A NEW USEFUL REAGENT FOR THE PREPARATION OF N-SULFINYLAMINES, NITRILES, ISOCYANIDES, AND CARBODIIMIDES UNDER MILD CONDITIONS
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Di-2-pyridyl sulfite is a very useful reagent for the preparation of N-sulfinylamines, nitriles, isocyanides, and carbodiimides in high yields under essentially neutral conditions.
- Kim, Sunggak,Yi, Kyu Yang
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p. 1925 - 1928
(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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- 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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- Biomimetic Study of Intramolecular Phosphoryl Group Transfer in Thioureas under Acid/Base and Stereoelectronic Control
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Reaction of dicyclohexylcarbodiimide with sterically hindered thiophosphoric esters 3 leads at -80 deg C to observable (31P NMR) S-phosphorylisothioureas 5.At 20 deg C in methylene chloride the same reaction does not give 5 but its N-phosphoryl isomer 4, together with 5', 2, and the counterion 3'.The equilibrium quantity of the N-phosphoryl isomer varies with the bulk of the R group (R = Ph > 2,6-Me2C6H3 > 2,5-i-Pr2C6H3).The equilibrium can also be either approached from 4 (which is isolable) or by treating the isothiouronium salt 5' with a strong amine base (such as the proton sponge), and in each case the same observed rate constant (= k1 + k-1) is obtained.The equilibrium can be displaced toward 5' in the presence of acid (HBF4 or Et3NH+) or toward the elimination products 2 and 3' in the presence of bases (tertiary amines).In the presence of excess acid the observed rate of reaction of 4 is independent of acid concentration and type, and the rate-determining step is assigned to the intramolecular N- -> S-phosphoryl group transfer (4 -> 5), governed by k1.In the presence of excess base the rate of reaction of 4 is independent of base type and concentration, and the step which is partly rate determining in this case is consistent with the conversion of 5 to 8 (k2) which is correctly oriented for elimination.The implications of the observation of this mobile equilibrium governed by the presence of acid or base catalysts to the question of the involvement of O- or N-phosphoryl intermediates in the mode of action of the coenzyme biotin is briefly discussed.
- Blonski, C.,Gasc, M. B.,Hegarty, A. F.,Klaebe, A.,Perie, J. J.
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p. 7523 - 7529
(2007/10/02)
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- The Dehydration of Ureas by Two-Phase Dichlorocarbene Reaction, a Synthetic Access to Substituted Cyanamides
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A wide variety of N,N-disubstituted ureas are dehydrated in the CHCl3/NaOH catalytic two-phase system under mild conditions.The sequence of urea-transamidation and dehydration thus offers a profitable approach to aprotic cyanamides.Among various tested PT-catalysts tertiary amines prove to be the most efficient and favourable ones.Tertiary amines may also be used advantageously in the transformation of carboxylic amides and thioamides to the corresponding nitriles.The application of the same technique is less suitable in the case of N-mono-substituted ureas, N,N'-disubstituted ureas as well as N(dialkylaminomethylidene)ureas, because consequent reactions of the primarily formed cyanamides predominate.Problems concerning the dehydration mechanism are elucidated in terms of HMO-perturbation theory.
- Schroth, W.,Kluge, H.,Frach, R.,Hodek, W.,Schaedler, H. D.
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p. 787 - 802
(2007/10/02)
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- Dehydration of ureas by organic phosphorus reagents into carbodiimides and their conversion into cyanoguanidines
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Carbodiimides were obtained from N,N'-disubstituted ureas by means of phosphorus compounds used as versatile dehydrating reagent.The reaction of carbodiimides with cyanamide under basic or acid catalysis provides a method for obtaining 1,3-cyanoguanidines in good yields.
- Palomo, Claudio,Mestres, Ramon
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p. 361 - 364
(2007/10/02)
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