- Base-Catalyzed Transcarbamoylation
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Inorganic bases such as NaH, KO t -Bu, NaOH, or KOH are efficient catalysts to promote the transcarbamoylation reaction between urethanes and a variety of primary and secondary alcohols under mild conditions. They constitute an alternative to organometallic catalysis and can be applied to aliphatic or aromatic urethanes.
- Rhoné, Beno?t,Semetey, Vincent
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Read Online
- (PPh4)2: A Copper Hydride Nanocluster with a Bisquare Antiprismatic Core
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Atomically precise coinage metal (Au, Ag, and Cu) nanoclusters (NCs) have been the subject of immense interest for their intriguing structural, photophysical, and catalytic properties. However, the synthesis of Cu NCs is highly challenging because of low reduction potential and high reactivity of copper, demonstrating the need for new synthetic methods using appropriate ligand combinations. By designing a diamine-assisted synthetic strategy, here we report the synthesis and total structure characterization of a box-like dianionic Cu NC [Cu32(PET)24H8Cl2](PPh4)2 coprotected by 2-phenylethanethiolate (PET), hydride, and chloride ligands. Its crystal structure comprises a rare bisquare antiprismatic Cu14H8 core, assembled by two square antiprisms by edge sharing, followed by hydride binding. The rod-shaped Cu14H8 core is clamped by two complex Cu7(PET)11Cl and two simple Cu2PET metal ligand frameworks, constructing the complete structure of Cu32 NC. The presence, number, and location of hydrides are established by combined experimental and density functional theory results. The electronic structure calculations show the cluster as a zero-free-electron system, reproduce well the measured optical absorption spectrum, and explain the main absorption features. Furthermore, the Cu32 cluster is found to be a highly active homogeneous catalyst for C-N bond formation in aniline carbonylation reactions at room temperature. We hope that new findings in this work will stimulate and expand the research on Cu and other active metal NCs.
- Baek, Woonhyuk,Bootharaju, Megalamane S.,Deng, Guocheng,H?kkinen, Hannu,Hyeon, Taeghwan,Lee, Sanghwa,Malola, Sami,Zheng, Nanfeng
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- Catalytic metathesis of carbon dioxide with heterocumulenes mediated by titanium isopropoxide
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The insertion of an isopropoxide ligand of titanium isopropoxide into heterocumulenes gives a product that carries out metathesis at elevated temperatures by undergoing insertion of a second heterocumulene in a head to head fashion, followed by an extrusion reaction. The Royal Society of Chemistry 2005.
- Ghosh, Rajshekhar,Samuelson, Ashoka G.
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Read Online
- Indirect reduction of CO2and recycling of polymers by manganese-catalyzed transfer hydrogenation of amides, carbamates, urea derivatives, and polyurethanes
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The reduction of polar bonds, in particular carbonyl groups, is of fundamental importance in organic chemistry and biology. Herein, we report a manganese pincer complex as a versatile catalyst for the transfer hydrogenation of amides, carbamates, urea derivatives, and even polyurethanes leading to the corresponding alcohols, amines, and methanol as products. Since these compound classes can be prepared using CO2as a C1 building block the reported reaction represents an approach to the indirect reduction of CO2. Notably, these are the first examples on the reduction of carbamates and urea derivatives as well as on the C-N bond cleavage in amides by transfer hydrogenation. The general applicability of this methodology is highlighted by the successful reduction of 12 urea derivatives, 26 carbamates and 11 amides. The corresponding amines, alcohols and methanol were obtained in good to excellent yields up to 97%. Furthermore, polyurethanes were successfully converted which represents a viable strategy towards a circular economy. Based on control experiments and the observed intermediates a feasible mechanism is proposed.
- Liu, Xin,Werner, Thomas
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p. 10590 - 10597
(2021/08/20)
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- Interrupted aza-Wittig reactions using iminophosphoranes to synthesize 11C-carbonyls
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A direct CO2-fixation methodology couples structurally diverse iminophosphoranes with various nucleophiles to synthesize ureas, carbamates, thiocarbamates, and amides, and is amenable for 11C radiolabeling. This methodology is practical, as demonstrated by the synthesis of >35 products and isolation of the molecular imaging radiopharmaceuticals [11C]URB694 and [11C]glibenclamide. This journal is
- Ismailani, Uzair S.,Munch, Maxime,Mair, Braeden A.,Rotstein, Benjamin H.
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supporting information
p. 5266 - 5269
(2021/06/06)
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- Nickel-Catalyzed Synthesis of N-(Hetero)aryl Carbamates from Cyanate Salts and Phenols Activated with Cyanuric Chloride
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A simple and efficient domino reaction has been designed and employed for the one-pot synthesis of N-(hetero)aryl carbamates through the reaction between alcohols and in-situ produced (hetero)aryl isocyanates in the presence of a nickel catalyst. The phenolic C?O bond was activated via the reaction of phenol with cyanuric chloride (2,4,6-trichloro-1,3,5-triazine (TCT)) as an inexpensive and readily available reagent. This strategy provides practical access to N-(hetero)aryl carbamates in good yields with high functional groups compatibility.
- Dindarloo Inaloo, Iman,Esmaeilpour, Mohsen,Majnooni, Sahar,Reza Oveisi, Ali
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p. 5486 - 5491
(2020/09/04)
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- An Fe3O4@SiO2/Schiff base/Cu(ii) complex as an efficient recyclable magnetic nanocatalyst for selective mono: N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids
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An efficient, convenient and novel method for the selective mono N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids in the presence of a recyclable magnetic Cu(ii) nanocatalyst is described. A variety of mono N-arylated O-alkyl thiocarbamates and O-alkyl carbamates were prepared in good to excellent yields with a broad range of aryl coupling partners. The magnetic nanocatalyst can be easily recovered with an external magnetic field and reused at least five times without noticeable leaching or loss of its catalytic activity. This cost-effective and eco-friendly methodology has some other advantages, such as easy preparation of the catalyst, simple workup procedure, and easy purification, which makes this protocol interesting for the users in various fields of pharmacology and biotechnology systems.
- Sardarian, Ali Reza,Dindarloo Inaloo, Iman,Zangiabadi, Milad
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p. 8557 - 8565
(2019/06/14)
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- A Fe3O4?SiO2/Schiff Base/Pd Complex as an Efficient Heterogeneous and Recyclable Nanocatalyst for One-Pot Domino Synthesis of Carbamates and Unsymmetrical Ureas
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A palladium-catalyzed domino method for the direct synthesis of carbamates and ureas has been developed by using readily available and economical starting materials (aryl halide, carbon monoxide, sodium azide, amines and alcohols) in a one-pot approach. The domino process underwent carbonylation, Curtius rearrangement, and nucleophilic addition. This protocol provides a step-economical and highly efficient reaction to access the wide range of valuable carbamates, symmetrical and unsymmetrical ureas with high yields under remarkable mild reaction conditions that are important factors in pharmaceutical science, biochemistry and agricultural industries. Furthermore, the magnetically recoverable nanocatalyst (Fe3O4?SiO2/Pd(II)) can be conveniently and swiftly recycled using external magnet and reused at least for seven times without noticeable loss of its catalytic activity.
- Inaloo, Iman Dindarloo,Majnooni, Sahar
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p. 6359 - 6368
(2019/11/05)
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- Carbon dioxide utilization in the efficient synthesis of carbamates by deep eutectic solvents (DES) as green and attractive solvent/catalyst systems
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A green and eco-friendly solvent/catalyst system based on a deep eutectic solvent (DES) was devised and developed for the simple synthesis of carbamates through three-component coupling of amines, alkyl halides and carbon dioxide (CO2). It was found that choline chloride:zinc(ii) chloride ([ChCl][ZnCl2]2) was very proficient and effective for the activation and utilization of CO2 in carbamate formation reactions from a wide scope of amines. Surprisingly, this strategy provides the desired carbamates under atmospheric CO2 pressure at room temperature. In particular, both aromatic and aliphatic amines were effective and demonstrated excellent yields. Besides, the [ChCl][ZnCl2]2 exhibited very high stability and also could be reused for at least five consecutive cycles without any significant loss of activity. It is worth noting that this is the first solvent/catalyst system which can be recycled successfully from the reaction mixture.
- Dindarloo Inaloo, Iman,Majnooni, Sahar
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p. 11275 - 11281
(2019/07/31)
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- Synthesis of N-(Hetero)aryl Carbamates via CuI/MNAO Catalyzed Cross-Coupling of (Hetero)aryl Halides with Potassium Cyanate in Alcohols
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An efficient route to N-(hetero)aryl carbamates was developed through CuI/MNAO [2-((2-methylnaphthalen-1-yl)amino)-2-oxoacetic acid] catalyzed cross-coupling of (hetero)aryl chlorides with potassium cyanate in alcohols at 120-130 °C. This method utilizes
- Kumar, S. Vijay,Ma, Dawei
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p. 2706 - 2713
(2018/03/09)
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- Ureas as safe carbonyl sources for the synthesis of carbamates with deep eutectic solvents (DESs) as efficient and recyclable solvent/catalyst systems
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A simple, efficient and eco-friendly one-pot synthesis of primary, N-mono- and N-disubstituted carbamates is developed from ureas. The corresponding carbamates were produced at 120 °C, within 18 h, and in the presence of a deep eutectic solvent as a recyclable catalytic system. The catalyst can be reused for several runs without any reduction in its activity. To demonstrate the utility of this approach, a wide variety of alcohols and phenols were studied to find a vast range of carbamate derivatives in moderate to high yields.
- Dindarloo Inaloo, Iman,Majnooni, Sahar
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p. 13249 - 13255
(2018/08/21)
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- An efficient one-pot synthesis of N,N′-disubstituted phenylureas and N-aryl carbamates using hydroxylamine-O-sulfonic acid
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We have developed an efficient one-pot method for the microwave-assisted synthesis of ureas and carbamates via a proposed Lossen rearrangement. Herein we report the first examples of the direct conversion of benzoyl chlorides into N,N′-disubstituted ureas and N-aryl carbamates using hydroxylamine-O-sulfonic acid as reagent. Using our general method, we have produced 11 examples of N,N′-disubstituted phenylureas in yields up to 95% using various substituted anilines, and primary and secondary amines. Additionally, we were able to generate a series of N-aryl carbamates in moderate yields using primary, secondary and tertiary alcohols.
- Bao, Jennifer,Kuik, Dale,Tranmer, Geoffrey K.
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supporting information
p. 5546 - 5553
(2018/06/12)
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- Direct Catalytic Synthesis of N-Arylcarbamates from CO2, Anilines and Alcohols
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The direct catalytic synthesis of carbamates from CO2, amines and methanol was achieved by controlling both the reaction equilibrium and the reactivity of the three components. The combination of CeO2 and 2-cyanopyridine was an effective catalyst, providing various carbamates including N-arylcarbamates in high selectivities.
- Tamura, Masazumi,Miura, Ayaka,Honda, Masayoshi,Gu, Yu,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 4835 - 4839
(2018/10/15)
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- METHOD FOR PRODUCING CARBAMATE
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PROBLEM TO BE SOLVED: To provide a method for producing carbamate in which a high yield can be obtained and the amount of by-products produced can be reduced. SOLUTION: In the method, carbamate is synthesized using at least one member selected from the group consisting of amine and derivative thereof, alcohol having 3 or more carbon atoms and carbon dioxide as a raw material, cerium oxide as a catalyst, and 2-cyanopyridine as a dehydrating agent. By using an alcohol having 3 or more carbon atoms, a high yield can be obtained and the amount of by-products produced can be reduced. In addition, the pressure of carbon dioxide can be lowered and the production can be of ease. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2018,JPO&INPIT
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Paragraph 0041; 0043; 0060; 0063; 0066; 0069
(2018/10/16)
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- Selective Synthesis of Secondary Arylcarbamates via Efficient and Cost Effective Copper-Catalyzed Mono Arylation of Primary Carbamates with Aryl Halides and Arylboronic Acids
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Abstract: An efficient, selective and cost-effective procedure has been developed for mono N-arylation of primary alkyl and benzyl carbamates with aryl iodides and bromides by incorporating CuI as an inexpensive and commercially available catalyst. Despite previous reports on C–N coupling reactions, this process does not need expensive ligands and takes advantage of readily available and inexpensive ethylenediamine (EDA) as the ligand. Reaction times were relatively short and related N-arylated carbamates were obtained in excellent yields. Interestingly, replacing CuI with Cu(OAc)2 allowed us to use arylboronic acids as coupling partner for this reaction. All products are well characterized by 1H- and 13C-NMR, MS, melting point, IR and CHNS techniques.
- Sardarian, Ali Reza,DindarlooInaloo, Iman,Zangiabadi, Milad
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p. 642 - 652
(2018/01/11)
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- Efficient preparation of carbamates by Rh-catalysed oxidative carbonylation: unveiling the role of the oxidant
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The synthesis of a wide variety of carbamates from amines, alcohols and carbon monoxide has been achieved by means of a Rh-catalysed oxidative carbonylation reaction that uses Oxone as a stoichiometric oxidant. In-depth studies on the reaction mechanism shed light on the intimate role of Oxone in the catalytic cycle.
- Iturmendi, Amaia,Iglesias, Manuel,Munárriz, Julen,Polo, Victor,Pérez-Torrente, Jesús J.,Oro, Luis A.
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supporting information
p. 404 - 407
(2017/01/03)
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- Fe3O4@SiO2/Schiff base/Pd complex as an efficient heterogeneous and recyclable nanocatalyst for chemoselective: N -arylation of O -alkyl primary carbamates
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An efficient, heterogeneous and cost effective method has been developed using an Fe3O4@SiO2/Schiff base/Pd complex as a magnetic and easily recyclable nanocatalyst for rapid and effective N-arylation of carbamates in good to excellent yield. The catalyst can be easily recovered and reused over six runs without significant decrease in the activity. Further highlights of this protocol are operational simplicity, versatility and relatively short reaction times.
- Sardarian,Zangiabadi,Inaloo, I. Dindarloo
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p. 92057 - 92064
(2016/10/11)
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- Copper-catalyzed carbonylation of anilines by diisopropyl azodicarboxylate for the synthesis of carbamates
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A Cu-catalyzed efficient methodology for the direct carbonylation of anilines has been developed. The N-H bond cleavage and N-C bond formation were notably achieved under solvent-free conditions and a variety of carbamates were synthesized from readily available anilines using diisopropyl azodicarboxylate (DIAD) as the carbonylating source.
- Usman, Muhammad,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
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p. 107542 - 107546
(2016/11/29)
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- Metal free oxidative coupling of aryl formamides with alcohols for the synthesis of carbamates
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A direct transformation of N-aryl formamides to the corresponding carbamates via the formation of isocyanate intermediates is achieved in good yields using hypervalent iodine as an oxidant. This journal is
- Reddy, N. Veera,Prasad, K. Rajendra,Reddy, P. Sudhir,Lakshmi Kantam,Reddy, K. Rajender
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p. 2172 - 2175
(2014/04/03)
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- Aniline carbamates: A versatile and removable motif for palladium-catalyzed directed c-h activation
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The aniline carbamate is introduced as a new removable directing group for C-H activation. Its versatility and ability as a directing group are demonstrated by its use in the ortho-arylation of a wide variety of aniline derivatives under palladium(II) catalysis, with symmetric diaryliodonium salts as aryl donors. The reaction differs from previously reported arylations in its selectivity and its mechanism, as elucidated by kinetic and isotopic experiments. The directing group can also be easily removed under a variety of conditions.
- Uhlig, Nick,Li, Chao-Jun
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supporting information
p. 12066 - 12070
(2015/03/31)
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- Activation of weak nucleophiles: Polyfluorocarbamates from polyfluoroalcohols via a fast radical reaction
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A new fast radical mechanism has been observed for the reaction of polyfluorinated alcohols and phenylisocyanate, very sensitive to the change of solvents and the concentration of reactants. The acidity of polyfluoroalcohols seems to be responsible for the observed new reactivity and evidences from kinetic studies, electron paramagnetic resonance, cyclic voltammetry, and photostimulation suggest that polyfluoroalkoxy radical is the key intermediate in the chain. To the best of our knowledge, it is the first time that a radical mechanism is described for the preparation of carbamates.
- Soto, Marc,Comalrena, Helena,Balduzzi, Ursula,Guirado, Gonzalo,Lloveras, Vega,Vidal-Gancedo, José,Sebastián, Rosa María,Marquet, Jordi
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supporting information
p. 6310 - 6313
(2013/11/06)
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- Preparation of ionic liquid-based vilsmier reagent from novel multi-purpose dimethyl formamide-like ionic liquid and its application
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In continuation of research to explore the applied potential of DMF-like ionic liquid, the ionic liquid version of N,N-dimethyliminiumchloride (Vilsmier reagent) has been synthesized from DMF-like ionic liquid and tested effectively for its capacity to achieve more useful organic transformations. The results show that DMF-like ionic liquid is world's first task specific ionic liquid which has catalyzed numerous diverse type of reaction and is multipurpose in its application. Thus a new term for this DMF-like ionic liquid has been coined that is DMF-like "multipurpose" ionic liquid. Copyright
- Hullio, Ahmed Ali,Mastoi
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scheme or table
p. 1647 - 1657
(2012/09/21)
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- Copper-catalyzed coupling of arylboronic acids with potassium cyanate: A new approach to the synthesis of aryl carbamates
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The copper-catalyzed coupling of aromatic boronic acids with potassium cyanate in the presence of an alcohol has been employed for the synthesis of arylcarbamates. This simple and highly efficient approach can be carried out in air at room temperature and, importantly, no base, ligand, or additive is required. Copyright
- Kianmehr, Ebrahim,Baghersad, Mohammad Hadi
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supporting information; experimental part
p. 2599 - 2603
(2011/11/29)
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- Selenium-catalyzed oxidative carbonylation of aniline and alcohols to n-phenylcarbamates
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A facile one-pot, phosgene-free synthesis of N-phenylcarbamates is demonstrated. Catalyzed by selenium, oxidative carbonylation of aniline with alcohols in the presence of carbon monoxide and oxygen affords the corresponding N-phenylcarbamates, mostly in fair to good yields. Selenium can be easily recovered because of its phase-transfer catalysis function. Copyright
- Zhang, Xiaopeng,Jing, Huanzhi,Zhang, Guisheng
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experimental part
p. 1614 - 1624
(2010/07/09)
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- Effect of successive increase in alcohol chains on reaction with isocyanates and isothiocyanates
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The reaction of isocyanates and isothiocyanates with long-chain alcohols, e.g. n-hexanol, n-heptanol and n-octanol, exclusively gave N-aryl-O-alkyl carbamates, while N-aryl-O-alkyl carbamates were formed along with symmetrical 1,3-disubstituted ureas and thioureas when the same reactions were carried out with small-chain alcohols at room temperature without using any solvent.
- Perveen, Shahnaz,Yasmin, Arfa,Khan, Khalid Mohammed
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experimental part
p. 18 - 23
(2010/04/23)
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- Cyanuric chloride: an efficient reagent for the Lossen rearrangement
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An efficient method for the Lossen rearrangement that uses 2,4,6-trichloro-1,3,5-triazine (TCT) as a promoter is reported. This procedure allowed the preparation of various carbamates, thiocarbamates, and ureas in good yields directly from the correspondi
- Hamon, Florian,Prié, Gildas,Lecornué, Frédéric,Papot, Sébastien
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experimental part
p. 6800 - 6802
(2010/04/27)
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- Photochemistry of sulfilimine-based nitrene precursors: Generation of both singlet and triplet benzoylnitrene
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(Graph Presented) Photolysis of N-benzoyl-S,S-diphenylsulfilimine or N-benzoyl dibenzothiophene sulfilimine produces PhNCO and also benzoylnitrene. Direct observation of the triplet nitrene, energetic differences between the singlet and triplet state of the nitrene, and oxygen quenching experiments suggest that the triplet nitrene derives from the triplet excited state of the sulfilimine precursors, rather than through equilibration of nearby singlet and triplet states of the nitrene itself. In acetonitrile, the formation of an ylide, followed by cyclization to the corresponding oxadiazole, is the predominant nitrene chemistry, occurring on the time scale of a few microseconds and few tens of microseconds, respectively. Trapping experiments with substrates such as cis-4-octene suggest that reactivity of the nitrene is mainly through the singlet channel, despite a fairly small energy gap between the singlet ground state and the triplet.
- Desikan, Vasumathi,Liu, Yonglin,Toscano, John P.,Jenks, William S.
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p. 6848 - 6859
(2008/02/11)
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- The influence of the structure of alcohols on the rate of N,N'-diphenylurea alcoholysis
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The kinetics and mechanism of the reaction between symmetrical diphenylurea and various alcohols in the absence of inert solvents were studied. The activation parameters of alcoholysis were determined. A correlation equation that described the influence of the nature of the alcohol on the rate of the reaction was obtained. Copyright
- Mantrov,Chimyashkin
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p. 688 - 691
(2007/10/03)
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- Reversible double insertion of aryl isocyanates into the Ti-O bond of titanium(IV) isopropoxide
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The insertion of phenyl isocyanate into titanium isopropoxide leads to the formation of a dimeric complex [Ti(OiPr)2(μ-O iPr){C6H5N(OiPr)CO}]2 (1) which has been structurally characterized. Reaction of titanium isopropoxide with two and more than 2 equiv. of phenyl isocyanate is complicated by competitive, reversible insertion between the titanium carbamate and titanium isopropoxide. The ligand formed by insertion of phenyl isocyanate into the titanium carbamate has been structurally characterized in its protonated form C6H5N{C(OiPr)O}C(O)N(H)C6H 5 (3aH). Insertion into the carbamate is kinetically favored whereas insertion into isopropoxide gives the thermodynamically favored product.
- Ghosh, Rajshekhar,Nethaji, Munirathinam,Samuelson, Ashoka G.
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p. 1282 - 1293
(2007/10/03)
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- Thermochemical Study of Complexation of Carbamates with Isocyanates in Solution
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Complexation of alkyl phenylcarbamates with isocyanates was studied calorimetrically. The compositions, stability constants, and enthalpies of formation of the complexes were determined. The stability of the complexes regularly increases with increasing electron-donor power of substituents in carbamates and electron-acceptor power of isocyanates.
- Gorbatov,Yablokova,Kheidorov
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p. 1838 - 1839
(2007/10/03)
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- Thermolysis of Alkyl N-Phenylcarbamates in the Presence of Hydroxy Compounds
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Kinetic and activation parameters of thermolysis of alkyl N-phenylcarbamates in the presence of hydroxy compounds in diglyme are determined. Hydroxy compounds accelerate thermolysis of carbamates. The initial stage of the reaction in the presence of alcohols and phenols is formation of a complex of carbamate with the hydroxy compound. The compositions of the complexes are determined thermochemically, and the stability constants and enthalpies of formation are calculated.
- Gorbatov,Yablokova,Kheidorov
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p. 1807 - 1810
(2007/10/03)
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- Carbon Dioxide as a Phosgene Replacement: Synthesis and Mechanistic Studies of Urethanes from Amines, CO2, and Alkyl Chlorides
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Several carbamate esters were synthesized from amines, carbon dioxide, and alkyl chlorides.The effect of added base on the yield and selectivity of carbamate ester formation was found to be highly important with the use of sterically hindered guanidine bases giving the best results.Relative rate studies were carried out giving the following order of reactivity between carbamate anions in acetonitrile with benzyl chloride giving carbamate esters: Et2NCO2(-) = Bu2NCO2(-) > t-BuNHCO2(-) = CyNHCO2(-) = s-BuNHCO2(-) > PhNHCO2(-) > CyCH2NHCO2(-) = n-octylNHCO2(-) = n-BuNHCO2(-).Rate studies were carried out with the diethyl, s-butyl, phenyl, and n-butyl carbamates and activation parameters were determined to be Et2NCO2(-), ΔH(excit.) = 11.8 kcal/mol, ΔS(excit.) = -33 eu; s-BuNHCO2(-), ΔH(excit.) = 12.8 kcal/mol, ΔS(excit.) = -33 eu; PhNHCO2(-), ΔH(excit.) = 14.3 kcal/mol, ΔS(excit.) = -28 eu; n-BuNHCO2(-), ΔH(excit.) = 23.4 kcal/mol, ΔS(excit.) = -3 eu.The unusual results obtained from the use of n-BuNHCO2(-) prompted further studies which showed that the rate of the reaction was inversely dependent on carbon dioxide pressure (20 psig CO2, k = 4.84E-4 M-1 s-1; 120 psig CO2, k = 1.83E-4 M-1 s-1).Nitrogen NMR spectroscopy indicated, via a labeling study with 15N amines and 13C enriched carbon dioxide, the formation of doubly inserted product from the addition of two carbon dioxides to ethylamine in acetonitrile.
- McGhee, William,Riley, Dennis,Christ, Kevin,Pan, Yi,Parnas, Barry
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p. 2820 - 2830
(2007/10/02)
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- Protein separation medium
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A separation medium for use in protein separation comprising a water-insoluble matrix carrying a plurality of polyamine groupings, the polyamine groupings having at least three basic nitrogen atoms, the basic nitrogen atoms being separated from each other by a chain of at least two intervening carbon atoms, there being a total of 5 such intervening carbon atoms when there is a total of three nitrogen atoms in each polyamine group, which may be used for at least partially purifying factor VIII.
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- Triazolecarboxamide herbicides
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Compounds of the formula: STR1 wherein X is O or S; R and R1 are substituted or unsubstituted alkyl, alkenyl, alkynyl or cycloalkyl or R and R1 may be joined to form a heterocyclic ring; R2 is substituted or unsubstituted cycloalkyl; and n is 0, 1 or 2 are disclosed as well as their postemergence and preemergence selective herbicide use against both monocot and dicot weeds in crops such as sugarbeets, cotton, soybeans and rice.
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- Catalyst for isocyanate trimerization
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A process for producing an isocyanate trimer and a process for producing an urethane with a catalyst for isocyanate trimerization or urethane formation, which comprises cesium fluoride or a tetraalkylammonium fluoride.
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- KINETICS AND MECHANISM OF THE ADDITION OF α-HYDROXY AND α-AMINO PHOPSPHONATES TO PHENYL ISOCYANATE
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Kinetics and mechanism of the addition of a series phosphorylated alcohols and amines with variable alkoxy substituents at the phosphorus atom to phenyl isocyanate have been studied by the spectrophotometric method.The adducts were isolated and characterized.The reactivity of the phosphonates is determined by steric and stereoelectronic effects of the substituents.The mechanism of the reaction and the nature of the dominating effect of a substituent can change, depending on the reaction conditions and the type of reaction series; the factors responsible for such changes have been clarified.
- Sayakhov, R. D.,Mironov, A. V.,Galkin, V. I.,Kutyrev, G. A.,Cherkasov, R. A.
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p. 1719 - 1725
(2007/10/02)
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- Homolytic Annulation by Reaction of Imidoyl Radicals with Diethyl Azodicarboxylate: a New Route to Nitrogen Heterocycle Derivatives
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An easily effected aromatic annulation is described, involving the reaction of arylimidoyl radicals with diethyl azodicarboxylate to give 1,2-dihydro-1,2-diethoxycarbonyl-benzo- and -pyrido-1,2,4-triazines.
- Leardini, Rino,Nanni, Daniele,Tundo, Antonio,Zanardi, Giuseppe
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p. 757 - 758
(2007/10/02)
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- THE REACTION OF IMIDOYL RADICALS WITH MULTIPLE CARBON-CARBON BONDS
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A general view on the reaction between imidoyl radicals and carbon-carbon double or triple bonds is given; the synthesis of substituted quinolines starting from imines and alkenes is described, pointing out the differences with respect to the analogous reaction performed with alkynes.
- Leardini, Rino,Nanni, Daniele,Tundo, Antonio,Zanardi, Giuseppe
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p. 637 - 642
(2007/10/02)
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- Reduction et photoreduction de derives de l'acide carbonique influence de l'hexamethylphosphorotriamide
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Photoreduction and reduction of carbonic acid derivatives in HMPT have been compared.The highest yield of alkane was obtained from N,N-dimethylthiocarbamates either by the photochemical method or by reduction with a dissolved metal.Competitive reactions have been characterized: - during the photoreduction not only the alkane but products of a photo-Fries rearrangement and products of a homolytic cleavage were detected; - basic reactions can compete with the reduction of carbonic acid derivatives by sodium in HMPT.
- Dembele, Albert,Deshayes, Henri,Pete, Jean-Pierre
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p. 671 - 680
(2007/10/02)
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- CARBONYLATION OF NITROSOBENZENES TO CARBAMATE ESTERS CATALYZED BY PALLADIUM AND CUPRIC ACETATES UNDER AMBIENT CONDITIONS
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Palladium acetate and cupric acetate are effective catalysts for the reaction of nitrosobenzenes with carbon monoxide and alcohol at room temperature and one atmosphere.
- Alper, Howard,Vasapollo, Giuseppe
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p. 6411 - 6412
(2007/10/02)
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- 5,6-Dihydro-1,2,4,6-thiatriazin-5-one-1,1-dioxides
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5,6-Dihydro-1,2,4,6-thiatriazin-5-one-1,1-dioxides of the formula STR1 where R1 is hydrogen, a metal atom or an unsubstituted or substituted ammonium radical, R2 is a saturated or unsaturated straight-chain aliphatic radical of up to 10 carbon atoms, a cycloaliphatic radical or 3 to 7 carbon atoms, a branched saturated or unsaturated aliphatic radical of 3 to 10 carbon atoms, a halogen-, alkoxy- or alkylmercapto-substituted aliphatic radical of 2 to 10 carbon atoms tetrahydrofuryl substituted methyl, a cycloalkoxy-substituted aliphatic radical of 4 to 10 carbon atoms, unsubstituted or halogen-substituted benzyl or phenyl, halophenyl, or alkylphenyl of a total of up to 10 carbon atoms, R3 is hydrogen, a straight-chain aliphatic radical of up to 10 carbon atoms, a cycloaliphatic radical of 3 to 7 carbon atoms, a branched aliphatic radical of 3 to 10 carbon atoms, haloalkyl, or alkoxyalkyl of 2 to 10 carbon atoms and X is oxygen and may also be sulfur if R2 is unsubstituted or halogen-substituted benzyl, processes for their preparation, and herbicides containing the above compounds.
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- Catalytic process for the manufacture of urethanes
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A process for the production of urethanes is provided in which an organic primary or secondary amine is contacted, in the substantial absence of reactive oxygen, with a source of carbon monoxide and an organic compound containing at least one hydroxyl group in the presence of a catalyst comprising a member selected from the group consisting of carbonyls of Co, Mo, Ti, Rh, Fe, Ni and mixtures thereof. Urethane yields and selectivities are further improved by conducting the reaction in the additional presence of an organic compound containing at least one C=N or C=C group. When such unsaturated organic compounds are employed, the catalyst can additionally comprise iridium carbonyl.
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- Process for preparing polymethylene-polyphenyl polyisocyanates
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A process for preparing polymethylene polyphenyl polyisocyanates, in which N-phenyl carbamic acid esters are subjected to a condensation reaction with formaldehyde, and the reaction product containing polymethylene polyphenyl polycarbamic acid esters and unreacted N-phenyl carbamic acid esters is thermally decomposed to obtain polymethylene polyphenyl polyisocyanates.
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- Reactions of Primary and Secondary Amines with Fluoronitrene Generated from Isopropyl N,N-Difluorocarbamate
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Isopropyl N,N-difluorocarbamate deaminates primary amines, RNH2, affording RH, N2, RNHCO2-i-C3H7, and RNH2*HF.With secondary amines, dibenzylamine gives bibenzyl, whereas pyrrolidine yields a ring-expansion product, 2,3,4,5-tetrahydropyridazine.The reactions are consistent with the generation of fluoronitrene and subsequent production of the intermediates RN=NH from RNH2 and R2N=N from R2NH.The advantages of using isopropyl N,N-difluorocarbamate as a source of fluoronitrene are discussed.
- Klopotek, David L.,Hobrock, Brice G.,Kovacic, Peter,Jones, Martin B.
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p. 1665 - 1667
(2007/10/02)
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- Cyclic esters of 3,4-dihydroxy-thiophene-1,1-dioxide compounds and 3,4-dihydroxy-cyclopentadienone compounds
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Cyclic esters of 3,4-dihydroxy-thiophene-1,1-dioxide and of the corresponding cyclopentadienone compound, and their manufacture. The compounds can be used as "solid forms" of phosgene, thiophosgene or oxalyl chloride, or as acyl transfer agents.
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