- Indium-mediated efficient conversion of azides to carbamates
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A novel and efficient method for the high yield preparation of carbamates by the reaction of azides with several chloroformates using indium metal in DMF at ambient temperature is described for the first time.
- Yadav,Subba Reddy,Kiran Kumar Reddy
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- Copper-Catalyzed Coupling of Amines with Carbazates: An Approach to Carbamates
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A new approach for the preparation of carbamatesviathe copper-catalyzed cross-coupling reaction of amines with alkoxycarbonyl radicals generated from carbazates is described. This environmentally friendly protocol takes place under mild conditions and is compatible with a wide range of amines, including aromatic/aliphatic and primary/secondary substrates.
- Wang, Song-Ning,Zhang, Guo-Yu,Shoberu, Adedamola,Zou, Jian-Ping
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p. 9067 - 9075
(2021/07/19)
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- Oxidative Route to Indoles via Intramolecular Amino-Hydroxylation of o-Allenyl Anilines
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A new intramolecular oxidative amino-hydroxylation of o-allenyl anilines is reported. Treatment of carbamate-protected anilines with lead(IV) carboxylates in dichloromethane at room temperature results in facile tandem C-N (allene cyclization) and C-O bon
- Lauta, Nicholas R.,Williams, Ryan E.,Smith, David T.,Kumirov, Vlad K.,Njardarson, Jon T.
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p. 10713 - 10723
(2021/07/31)
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- Method for synthesizing P-chloroO-toluidine
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The invention discloses a method for synthesizing p-chloroo-toluidine, which comprises the following steps: synthesizing o-toluidine and a protective agent in an organic solvent to obtain an amino-protected intermediate. The amino protected intermediate is added into hydrochloric acid, an oxidant is added for chlorination reaction, and a chlorination product is obtained. The chlorinated product is removed and the amino protecting group is removed to give p-chloroo-toluidine. The method for synthesizing p-chloroo-toluidine provided by the invention is high in yield, simple to operate, less in three wastes, high in product content and good in quality, and can be suitable for industrial mass production.
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Paragraph 0098-0099
(2021/10/05)
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- Methoxycarbonylation of Alkyl-, Cycloalkyl-, and Arylamines with Dimethyl Carbonate in the Presence of Binder-Free Zeolite
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Abstract: Methyl N-alkyl-, N-cycloalkyl-, and N-arylcarbamates were synthesized by reaction of the correspondingamines with dimethyl carbonate in the presence of binder-free FeHY zeolite. Theoptimal conditions (reactant ratio, amount of the catalyst, temperature,reaction time) were found to afford the target products with high yields.
- Khazipova, A. N.,Khusnutdinov, R. I.,Mayakova, Yu. Yu.,Shchadneva, N. A.
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p. 1228 - 1235
(2020/10/02)
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- Preparation method of pyridine quinazoline intermediate (by machine translation)
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The invention discloses a preparation method of a pyridine quinazoline intermediate, wherein: the 2 - preparation method of the, pyridine quinazoline intermediate comprises, the following steps, of: performing, substitution reaction and 3 - ring-forming r
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Paragraph 0011; 0015; 0019; 0023; 0027; 0031
(2020/02/14)
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- PRODUCTION OF N-SUBSTITUTED AROMATIC HYDROXYLAMINE
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An economic, one-step method for the production of N-substituted aromatic hydroxylamines of formula (I) [in-line-formulae]R—N(OH)—C(═O)—(O)R1??(I),[/in-line-formulae] with hydrogen, by catalytic hydration with possibly modified hydration catalysts in an aprotic solvent and in the presence of a halogen formic acid ester and in some cases in the presence of a base.
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Paragraph 0053
(2020/01/12)
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- Zr-MOF-808@MCM-41 catalyzed phosgene-free synthesis of polyurethane precursors
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In this work, a catalytic method is presented for the synthesis of aromatic carbamates from aromatic amines using dimethyl carbonate instead of phosgene as a green and safe reaction process. Microcrystalline Zr-MOF-808 is reported as an active and efficient heterogeneous catalyst for the selective carbamoylation of anilines and industrially relevant aromatic diamines, under mild reaction conditions with near quantitative yields. We have accomplished the selective growth of well-dispersed Zr-MOF-808 nanocrystals within the mesoporous material MCM-41. A superior catalytic performance of the Zr-MOF-808@MCM-41 is demonstrated that together with increased stability stands out as an advantageous heterogeneous catalyst for polyurethane production. In situ FTIR studies have allowed a better understanding of the reaction pathway at the molecular level when the active MOF catalyst is present.
- Rojas-Buzo, Sergio,García-García, Pilar,Corma, Avelino
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p. 146 - 156
(2019/01/10)
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- Electrochemical Hofmann rearrangement mediated by NaBr: Practical access to bioactive carbamates
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An electrochemical Hofmann rearrangement is reported. With the mediation of NaBr, highly corrosive and toxic halogens are avoided. Moreover, this efficient and green approach is well compatible with a broad range of amides, including several commercial medicine derivatives, and provides direct access to synthetically useful carbamates. The synthetic utility of this method is also demonstrated by the preparation of 15N labeling carbamate and gram-scale synthesis of Amantadine.
- Li, Lijun,Xue, Mengyu,Yan, Xin,Liu, Wenmin,Xu, Kun,Zhang, Sheng
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supporting information
p. 4615 - 4618
(2018/07/06)
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- A PROCESS FOR THE SYNTHESIS OF AROMATIC CARBAMATES
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The present invention discloses a process for the synthesis of aromatic carbamates from amine with dialkyl carbonate in the presence of binary or ternary mixed metal oxide catalyst. The present invention further discloses the yield of said aromatic carbamate in the range of 60 to 99%. Further, the ratio of amine to dialkyl carbonate is in the range of 1:2 to 1:30.
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Page/Page column 13; 14
(2018/12/13)
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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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- Iodoarene-catalyzed oxidative transformations using molecular oxygen
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Molecular oxygen serves as a useful oxidant for the glycol scission of 1,2-diols and the Hofmann rearrangement of primary amides using pentamethyliodobenzene as a catalyst. The use of isobutyraldehyde and Lewis basic nitriles under O2 enabled the iodine(i)/(iii) catalytic cycle, where in situ-generated peracid acts as a terminal oxidant.
- Miyamoto,Yamashita,Narita,Sakai,Hirano,Saito,Wang,Ochiai,Uchiyama
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supporting information
p. 9781 - 9784
(2017/09/07)
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- Palladium-Catalyzed Carbamate-Directed Regioselective Halogenation: A Route to Halogenated Anilines
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This study describes an efficient method for ortho-selective halogenation of N-arylcarbamates under mild conditions for the first time. Although being weakly coordinating, N-arylcarbamates act very well as a removable directing group for activation of C-H bonds. The developed procedure results in extremely valuable halogenated N-arylcarbmates that can further be hydrolyzed to halogenated anilines. The obtained reaction conditions showed broad scope and wide functional group tolerance. All the products were formed in good yields with extremely high selectivity.
- Moghaddam, Firouz Matloubi,Tavakoli, Ghazal,Saeednia, Borna,Langer, Peter,Jafari, Behzad
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p. 3868 - 3876
(2016/05/24)
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- Palladium-Catalyzed Decarboxylative Synthesis of Arylamines
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A novel approach has been developed for the synthesis of arylamines via the palladium-catalyzed intramolecular decarboxylative coupling (IDC) of aroyloxycarbamates, obtained in situ by reacting aryl carboxylic acids with hydroxycarbamates. The reaction offers facile access to structurally diverse arylamines with the site-specific formation of the C(sp2)-N bond under mild conditions.
- Dai, Qipu,Li, Peihe,Ma, Nuannuan,Hu, Changwen
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supporting information
p. 5560 - 5563
(2016/11/17)
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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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- (Tosylimino)phenyl-λ3-iodane as a reagent for the synthesis of methyl carbamates via hofmann rearrangement of aromatic and aliphatic carboxamides
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A new, mild procedure for the Hofmann rearrangement of aromatic and aliphatic carboxamides using (tosylimino)phenyl-λ3-iodane, PhINTs, as a reagent is reported. Because of the mild reaction conditions, this method is particularly useful for the Hofmann rearrangement of substituted benzamides, which usually afford complex reaction mixtures with other hypervalent iodine oxidants. The mild reaction conditions and high selectivity in the reaction of carboxamides with PhINTs allow the isolation of the initially formed labile isocyanates or their subsequent conversion to stable carbamates by treatment with alcohols.
- Yoshimura, Akira,Luedtke, Matthew W.,Zhdankin, Viktor V.
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p. 2087 - 2091
(2012/05/05)
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- Palladium-catalyzed carbonylation of amines: Switchable approaches to carbamates and N,N′-disubstituted ureas
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Switchable access to carbamates and ureas has been developed by solvent control palladium-catalyzed carbonylation of aromatic amines under an atmosphere of carbon monoxide. A variety of N-phenylcarbamates and N,N′- diphenylureas was easily synthesized in good to excellent yields from readily available aromatic amines under mild conditions. Copyright
- Guan, Zheng-Hui,Lei, Hao,Chen, Ming,Ren, Zhi-Hui,Bai, Yinjuan,Wang, Yao-Yu
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supporting information; experimental part
p. 489 - 496
(2012/04/04)
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- Synthesis of methyl-1-(tert -butoxycarbonylamino)-2- vinylcyclopropanecarboxylate via a hofmann rearrangement utilizing trichloroisocyanuric acid as an oxidant
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A trichloroisocyanuric acid (TCCA) mediated Hofmann rearrangement was utilized to synthesize methyl-1-(tert-butoxycarbonylamino)-2- vinylcyclopropanecarboxylate. A variety of functional groups are tolerated in this reaction including vinyl, cyclopropyl, pyridyl, aryl, benzyl, and nitro groups.
- Crane, Zackary D.,Nichols, Paul J.,Sammakia, Tarek,Stengel, Peter J.
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supporting information; experimental part
p. 277 - 280
(2011/03/20)
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- A microfluidic flow chemistry platform for organic synthesis: the Hofmann rearrangement
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We report on the use of commercially available chemical microreactors to effect the Hofmann rearrangement of aromatic amides to the corresponding carbamates. Crown Copyright
- Palmieri, Alessandro,Ley, Steven V.,Hammond, Kelvin,Polyzos, Anastasios,Baxendale, Ian R.
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scheme or table
p. 3287 - 3289
(2009/08/07)
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- Unexpected Reaction of Oximinoacetoacetate with Amines: A Novel Synthesis of Carbamates
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The synthesis of alkyl carbamates by a solvent-free reaction of oximinoacetoacetate and amine at 130C is reported. A preliminary mechanism to this unexpected reaction is also given.
- Elghamry, Ibrahim
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experimental part
p. 3010 - 3015
(2009/12/01)
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- Efficient palladium/1,10-phenanthroline-catalyzed reductive carbonylation of mono- and dinitroarenes to urethanes in phosphonium salt ionic liquids
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(Chemical Equation Presented) The highly reactive and selective reductive carbonylation of mono- and dinitroarenes to the corresponding mono- and diurethanes was carried out in the presence of a PdCl2/Phen catalytic system, using PSIL110[C14H29(C6H 13)3P+PF6-] as the ionic liquid under mild reaction conditions. No cocatalyst is required.
- Yang, Qian,Robertson, Al,Alper, Howard
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experimental part
p. 5079 - 5082
(2009/05/07)
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- Synthesis of functionalized carbamates through a palladium-catalyzed reductive carbonylation of substituted nitrobenzenes
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The palladium-catalyzed reductive carbonylation of ortho and para-substituted nitrobenzenes has proven to be an attractive route for the synthesis of functionalized carbamates. For the Pd(1,10-phenanthroline)2(triilate}2 catalyst system, the scope of the reaction has been studied. Substrates with electron-donating substituents at the para position were found to decrease the catalytic activity, most probably as a result of their relatively low oxidizing capacity. The selectivity towards the desired carbamate, however, was increased for these substrates. Under the influence of electron-withdrawing substituents the azoxybenzene and azobenzene derivatives became important side products. Introduction of large steric hindrance at the ortho position of the nitro substrates gave rise to an interesting side reaction, viz. methoxylation of the aromatic ring. The methoxylation reaction appeared to occur on an intermediate species in the catalytic cycle. Several functionalities have shown to be resistant to the reaction conditions required for the conversion of the nitro group. Especially with 4-nitrobenzoic acid, an extremely high activity and selectivity was found, thus yielding a very convenient synthesis for N-protected amines containing carboxylic acid functions. VCH Verlagsgesellschaft mbH.
- Wchman, Petra,Borst, Leo,Kamer, Paul C. J.,Van Leeuwen, Piet W. N. M.
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- Indirect electrochemical carbonylation of aromatic amines with a palladium catalyst
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Aromatic amines are converted to carbamates under very mild conditions, using carbon monoxide, palladium (II) acetate and copper (II) acetate in combination with anodic reoxidation.
- Hartstock, Frederick W.,Herrington, Deborah G.,McMahon, Launa B.
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p. 8761 - 8764
(2007/10/02)
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- NEW METHOD FOR HOFMANN REARRANGEMENT
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Treatment of a series of primary aliphatic and aromatic carboxamides (1a-1m) with NBS-Hg(OAc)2-R'OH (A), dibromantin-Hg(OAc)2-R'OH (B), NBS-AgOAc-R'OH (C), or dibromantin-AgOAc-R'OH (D) in DMF under argon provides corresponding carbamates (2a-2m) in nearly quantitative yields.
- Jew, Sang-sup,Park, Hyeung Geun,Park, Hee-Joo,Park, Min-soo,Cho, Youn-sang
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p. 1559 - 1562
(2007/10/02)
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- Halogenation Using Quatenary Ammonium Polyhaloides. IX. One-Step Syntheses of Acylureas and Carbamates from Amides by Use of Tetrabutylammonium Tribromide and DBU
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The reaction of amides with tetrabutylammonium tribromide (TBA Br3) (0.5 equiv) and DBU (one equiv) in dichloromethane at room temperature gave N-substituted acylureas in fairly good yields.In the presence of alcohols, the reaction of amides with TBA Br3 (one equiv) and DBU (two equiv) gave N-substituted carbamates.
- Fujisaki, Shizuo,Tomiyasu, Kazushi,Nishida, Akiko,Kajigaeshi, Shoji
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p. 1401 - 1403
(2007/10/02)
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- Process for the manufacture of carbamates
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A process for the production of carbamates 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, an organic compound containing at least one hydroxyl group and a source of sulfur, selenium or tellurium, in the presence of an effective amount of a catalyst selected from the group consisting of non-halide compounds and complexes of metals of Groups IVB, VB, VIB, VIIB, VIII, IB and IIIA of the Periodic Table. Further improved results are obtained by employing in the reaction zone at least one promoter selected from the group consisting of metals of Group IA and IIA of the Periodic Table.
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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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- Promoted method for producing carbamates
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A process for the production of carbamates is provided which comprises contacting an organic primary or secondary amine with a source of carbon monoxide, an organic compound containing at least one hydroxyl group and a source of sulfur, selenium or tellurium, in the presence of a catalyst for the reaction and in the presence of at least one member selected from the group consisting of disulfides of the formula wherein R1 and R2 comprise members selected from the group consisting of alkyl, aryl, cycloalkyl, alkaryl, aralkyl, heterocyclic, alkenyl, alkynyl, alkanoyl, aranoyl, halogenated derivatives of the foregoing groups, and derivatives of the foregoing groups in which one or more carbon atoms is replaced by an oxygen atom.
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