- Broad Scope and High-Yield Access to Unsymmetrical Acyclic [11C]Ureas for Biomedical Imaging from [11C]Carbonyl Difluoride
-
Effective methods are needed for labelling acyclic ureas with carbon-11 (t1/2=20.4 min) as potential radiotracers for biomedical imaging with positron emission tomography (PET). Herein, we describe the rapid and high-yield syntheses of unsymmet
- Jakobsson, Jimmy E.,Jana, Susovan,Lu, Shuiyu,Pike, Victor W.,Telu, Sanjay
-
supporting information
p. 10369 - 10376
(2021/06/07)
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- Lanthanum(III) Trifluoromethanesulfonate Catalyzed Direct Synthesis of Ureas from N-Benzyloxycarbonyl-, N -Allyloxycarbonyl-, and N -2,2,2-Trichloroethoxycarbonyl-Protected Amines
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A novel lanthanum triflate mediated conversion of N -benzyloxycarbonyl-, N -allyloxycarbonyl-, and N -trichloroethoxycarbonyl-protected amines into nonsymmetric ureas was discovered. In this study, lanthanum triflate was found to be an effective catalyst for preparing various nonsymmetric ureas from protected amines. A variety of protected aromatic and aliphatic carbamates reacted readily with various amines in the presence of lanthanum triflate to generate the desired ureas in high yields. This result demonstrated that this novel lanthanum triflate catalyzed preparation of ureas from Cbz, Alloc, and Troc carbamates can be employed for the formation of various urea structures.
- Bui, Tien Tan,Kim, Hee-Kwon
-
supporting information
p. 997 - 1002
(2020/06/17)
-
- Visible-light-promoted oxidative desulphurisation: A strategy for the preparation of unsymmetrical ureas from isothiocyanates and amines using molecular oxygen
-
A green and efficient visible-light promoted oxidative desulphurisation protocol has been proposed for the construction of unsymmetrical ureas under mild conditions with broad substrate scope and good functional group tolerance. Most appealingly, the reaction can proceed smoothly without adding any strong oxidants. Control experiments and computational studies support a mechanism involving water-assisted in situ generation of thioureas and photocatalytic oxidative desulphurisation. The present method provides a promising synthesis strategy for the formation of diverse and useful unsymmetrical urea derivatives in the fields of pharmaceutical and synthetic chemistry.
- Deng, Weiseng,Gan, Ziyu,Jiang, Yuan-Ye,Li, Guoqing,Yan, Qiuli,Yang, Daoshan
-
supporting information
p. 2956 - 2962
(2020/06/17)
-
- Structure–activity relationships (SARs) of α- ketothioamides as inhibitors of phosphoglycerate dehydrogenase (PHGDH)
-
For many years now, targeting deregulation within cancer cells’ metabolism has appeared as a promising strategy for the development of more specific and efficient cancer treatments. Recently, numerous reports highlighted the crucial role of the serine synthetic pathway, and particularly of the phosphoglycerate dehydrogenase (PHGDH), the first enzyme of the pathway, to sustain cancer progression. Yet, because of very weak potencies usually in cell-based settings, the inhibitors reported so far failed to lay ground on the potential of this approach. In this paper, we report a structure–activity relationship study of a series of α-ketothioamides that we have recently identified. Interestingly, this study led to a deeper understanding of the structure–activity relationship (SAR) in this series and to the identification of new PHGDH inhibitors. The activity of the more potent compounds was confirmed by cellular thermal shift assays and in cell-based experiments. We hope that this research will eventually provide a new entry point, based on this promising chemical scaffold, for the development of therapeutic agents targeting PHGDH.
- Spillier, Quentin,Ravez, Séverine,Unterlass, Judith,Corbet, Cyril,Degavre, Charline,Feron, Olivier,Frédérick, Rapha?l
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-
- Method for preparing asymmetric urea compound (by machine translation)
-
The invention provides a vehicle CO. 2 A method. for synthesizing an asymmetric urea compound by carbonylation coupling reaction of the carbonylation reagent is: and the aromatic, aliphatic primary amine compound and the aliphatic secondary amine compound and the normal pressure (100 °C, diglyme), can be efficiently prepared by using a common Lewis base and a hydrogen silane as the accelerator/CO under mild conditions. 2 The reaction produces a corresponding asymmetric urea compound. containing different functional groups, the process being operated at atmospheric pressure CO. 2 The use of an inexpensive Lewis base and, industrial silicon waste PMHS( for the green non-toxic carbonylation reagent) avoids toxic carbonylation reagents, high pressure, as an accelerator CO. 2 , The use, of the expensive dehydrating agent and the noble metal does not need to purify and separate the intermediate, and the pure product, is obtained by simple suction filtration separation after the reaction is ended . is a high efficiency, novel synthetic method . The commercial herbicide NEBURON. is successfully prepared by using the method. (by machine translation)
- -
-
Paragraph 0043-0048
(2020/03/25)
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- Graphene Oxide: A Metal-Free Carbocatalyst for the Synthesis of Diverse Amides under Solvent-Free Conditions
-
An environmentally friendly, inexpensive, carbocatalyst, graphene oxide (GO) promoted efficient, metal-free transamidation of various carboxamides with aliphatic, cyclic, and aromatic amines is demonstrated. The protocol is equally applicable to phthalimide, urea, and thioamide determining its adaptability. The oxygenated functionalities such as carbonyl (?C=O), epoxy (?O?), carboxyl (?COOH) and hydroxyl (?OH), present on graphene oxide surface impart acidic properties to the catalyst. The graphene oxide being heterogeneous in nature, work efficiently under solvent-free reaction conditions providing desired products in good to excellent yields. The one-pot synthesis of 2,3-Dihydro-5H-benzo[b]-1,4-thiazepin-4-one moiety by GO catalyzed Aza Michael addition followed by intramolecular transamidation is also described. A plausible reaction mechanistic pathway involving H-bonding is discussed. The graphene oxide can be recycled and reused up to five cycles without much loss in catalytic activity. (Figure presented.).
- Patel, Khushbu P.,Gayakwad, Eknath M.,Patil, Vilas V.,Shankarling, Ganapati S.
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supporting information
p. 2107 - 2116
(2019/03/26)
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- CaI2-Catalyzed direct transformation of: N -Alloc-, N -Troc-, and N -Cbz-protected amines to asymmetrical ureas
-
A novel and facile CaI2-catalyzed direct synthesis of asymmetrical ureas from N-Alloc-, N-Troc-, and N-Cbz-protected amines is developed. In this study, the efficient reaction of Alloc-, Troc-, and Cbz-carbamates with amines in the presence of catalytic CaI2 successfully generated various asymmetrical ureas. This catalytic synthetic procedure provided the desired ureas via reactions of these protected aromatic and aliphatic amines with various amines in high yields without side products. This suggests that novel direct synthesis of ureas from Alloc-, Troc-, and Cbz-carbamates can be a promising approach for the synthesis of useful ureas.
- Tran, Van Hieu,Kim, Hee-Kwon
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p. 14093 - 14101
(2019/09/18)
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- Efficient Direct Halogenation of Unsymmetrical N -Benzyl- and N -Phenylureas with Trihaloisocyanuric Acids
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A simple and efficient methodology for the direct halogenation of N -phenylureas was developed using trihaloisocyanuric acids in acetonitrile at room temperature. This protocol proved to be effective for the construction of N -phenylureas with different patterns of substitution. Additionally, less reactive N -benzylureas were halogenated in the presence of a mixture of trifluoroacetic acid and acetonitrile at room temperature.
- Sanabria, Carlos M.,Costa, Bruno B. S.,Viana, Gil M.,De Aguiar, Lúcia C. S.,De Mattos, Marcio C. S.
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supporting information
p. 1359 - 1367
(2017/12/26)
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- An efficient one-pot synthesis of N,N′-disubstituted phenylureas and N-aryl carbamates using hydroxylamine-O-sulfonic acid
-
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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- Chemoselective isocyanide insertion into the N-H bond using iodine-DMSO: Metal-free access to substituted ureas
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Insertion of isocyanides into the N-H bond gives access to many medicinally important and structurally diverse complex nitrogen-containing heterocycles. Although the transition metal catalyzed isocyanide insertion into the N-H bond is very common, polymerization of isocyanides in the presence of a transition metal and their strong coordination with metals are the common drawbacks. On the other hand, the inertness of most of the isocyanides towards amines in the absence of a metal catalyst has stymied the growth of the metal-free approach for isocyanide insertion into amines. As a result, only a handful of metal catalysed methods with limited substrate scopes have been reported for the synthesis of ureas via isocyanide insertion into amines and no metal-free version has been reported yet. Interestingly, chemoselective isocyanide insertion into amines has not been reported in the literature. We employed the I2-DMSO reagent system for the chemoselective synthesis of ureas, where isocyanides react with aliphatic amines only, while aromatic amines need a nucleophilic activator (DABCO) to facilitate the formation of ureas. This method gave direct and chemoselective access to ureas by evading the commonly used yet toxic isocyanates.
- Bora, Porag,Bez, Ghanashyam
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supporting information
p. 8363 - 8366
(2018/08/03)
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- Facile direct synthesis of unsymmetrical ureas from N-Alloc-, N-Cbz-, and N-Boc-protected amines using DABAL-Me3
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A practical synthetic method for the direct synthesis of unsymmetrically substituted ureas from N-Alloc-, N-Cbz-, and N-Boc-protected amines is described. In this study, efficient direct conversion of the Alloc-, Cbz-, and Boc-carbamate compounds to ureas was achieved in the presence of DABAL-Me3, an air stable and easily handled reagent. Using this reaction method, both protected aromatic and aliphatic amines were successfully transformed into various trisubstituted and tetrasubstituted ureas with high yields without side product. Our findings offer promising guidelines for direct preparation of useful ureas from N-Alloc-, N-Cbz-, and N-Boc-carbamates.
- Kang, Soosung,Kim, Hee-Kwon
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p. 4036 - 4046
(2018/06/13)
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- 1,3,4-OXADIAZOLE DERIVATIVE COMPOUNDS AS HISTONE DEACETYLASE 6 INHIBITOR, AND THE PHARMACEUTICAL COMPOSITION COMPRISING THE SAME
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The present invention relates to novel compounds having histone deacetylase 6 (HDAC6) in-hibitory activity, stereoisomers thereof or pharmaceutically acceptable salts thereof, the use thereof for the preparation of therapeutic medicaments, pharmaceutical compositions containing the same, a method for treating diseases using the composition, and methods for preparing the novel compounds. The novel compounds, stereoisomers thereof or pharmaceutically acceptable salts thereof according to the present invention have histone deacetylase (HDAC) inhibitory activity and are effective for the prevention or treatment of HDAC6-mediated diseases, including infectious diseases; neoplasms; endocrine, nutritional and metabolic diseases; mental and be-havioral disorders; neurological diseases; diseases of the eye and adnexa; cardiovascular diseases; respiratory diseases; digestive diseases; diseases of the skin and subcutaneous tissue; diseases of the musculoskeletal system and connective tissue; or congenital malformations, de? formations and chromosomal abnormalities.
- -
-
Paragraph 3344-3346
(2017/02/28)
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- Highly Regioselective Iodination of N-Phenylureas with Iodine/Trichloroisocyanuric Acid
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An efficient regioselective iodination of N-phenylureas was developed using iodine/trichloroisocyanuric acid in acetonitrile at room temperature. This protocol proved to be effective on a broad range of substituted N-phenylureas, forming the p-iodinated compounds in 65-96% yield under mild and neutral conditions.
- Sanabria, Carlos M.,do Casal, Mariana T.,De Souza, Raphael B. A.,De Aguiar, Lúcia C. S.,De Mattos, Marcio C. S.
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supporting information
p. 1648 - 1654
(2017/03/21)
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- Synthesis of ureas in the bio-alternative solvent Cyrene
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Cyrene as a bio-alternative solvent: a highly efficient, waste minimizing protocol for the synthesis of ureas from isocyanates and secondary amines in the bio-available solvent Cyrene is reported. This method eliminated the use of toxic solvents, such as
- Mistry, Liam,Mapesa, Kopano,Bousfield, Thomas W.,Camp, Jason E.
-
supporting information
p. 2123 - 2128
(2017/07/24)
-
- KI Catalyzed Nitrogenation of Aldehydes and Alcohols: Direct Synthesis of Carbamoyl Azides and Ureas
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An efficient KI catalyzed nitrogenation of aldehydes and alcohols for the direct synthesis of carbamoyl azides and ureas via a radical process has been developed. The simple operating procedures, the readily available starting materials including aldehydes, alcohols and amines, as well as the utility of the products all make this strategy very attractive.
- Song, Song,Feng, Peng,Zou, Miancheng,Jiao, Ning
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p. 845 - 848
(2017/06/27)
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- Nano-Magnetic Sulfonic Acid Catalyzed Facile Synthesis of Diverse Amide Derivatives
-
The excellent surface catalytic potential of Fe3O4-OSO3H is utilized in the synthesis of symmetrically and unsymmetrically substituted urea derivatives via transamidation reactions. The scope of the surface catalysis is further extended in transamidation reactions of cyclic and acyclic amide derivatives, and in the amidation of fatty acids. In both transamidation and amidation reactions, the catalyst is reusable up to five times without significant loss in its activity.
- Kothandapani, Jagatheeswaran,Ganesan, Asaithampi,Ganesan, Subramaniapillai Selva
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p. 685 - 692
(2017/01/25)
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- A high-yielding, expeditious, and multicomponent synthesis of urea and carbamate derivatives by using triphenylphosphine/trichloroisocyanuric acid system
-
An efficient method for the synthesis of urea and carbamate derivatives from amines and alcohols is described by using triphenylphosphine (PPh3)/trichloroisocyanuric acid system. The protocol allows for the preparation of symmetrical, unsymmetrical di, tri-, and tetra-substituted ureas and carbamates and is tolerant of a wide range of functional groups. To optimize the reaction conditions, experimental variables including temperature, the concentration of amine and alcohol, solvent, and reaction time were studied. Satisfactory yields were obtained at the optimized conditions. The present methodology is experimentally simple, mild, and represents a valuable alternative to the existing methods.
- Ghodsinia, Sara S.E.,Akhlaghinia, Batool
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p. 104 - 110
(2016/01/25)
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- A Facile and Efficient Method for the Formation of Unsymmetrical Ureas Using DABAL-Me3
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A practical synthetic method for the formation of unsymmetrical-substituted ureas is described. The synthesis of the unsymmetrical ureas was readily performed from 2,2,2-trichloroethyl carbamate compounds by treatment of amines with bis(trimethylaluminum)-1,4-diazabicyclo[2.2.2]octane (DABAL-Me3). Using this reaction protocol, various trisubstituted and tetrasubstituted ureas were synthesized in high yields. This study offers a promising approach for the facile synthesis of a variety of unsymmetrical ureas from 2,2,2-trichloroethyl carbamates.
- Jeong, Byung-Hoon,Kim, Hee-Kwon,Thompson, David H.
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p. 805 - 810
(2016/08/09)
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- A facile method for the preparation of unsymmetrical ureas utilizing zirconium (IV) chloride
-
A facile synthetic method for the preparation of unsymmetrical ureas from amines is described. Carbamoyl imidazole compounds were prepared by the reaction of 1, 1-carbonyldiimidazole with primary or secondary amines, and further activation by treatment with zirconium(IV) chloride to generate the desired urea. This reaction protocol was applied to the synthesis of tri and tetrasubstituted ureas with high yields. This study provides an alternative guideline for the practical preparation of various unsymmetrical ureas.
- Lee, Anna,Kim, Hee-Kwon,Thompson, David H.
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p. 154 - 160
(2016/02/26)
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- Facile one-pot synthesis of unsymmetrical ureas, carbamates, and thiocarbamates from Cbz-protected amines
-
A novel one-pot synthesis of unsymmetrical ureas, carbamates and thiocarbamates from Cbz-protected amines has been developed. In the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, isocyanates are generated in situ, which facilitate rapid reaction with amines, alcohols, and thiols to afford the corresponding ureas, carbamates and thiocarbamates in high yields.
- Kim, Hee-Kwon,Lee, Anna
-
supporting information
p. 7345 - 7353
(2016/08/05)
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- Synthesis of unsymmetrical phenylurea derivatives via oxidative cross coupling of aryl formamides with amines under metal-free conditions
-
A new synthetic approach for phenylurea derivatives involving the cross coupling of N-aryl formamides with amines through the formation of isocyanate intermediates in the presence of hypervalent iodine reagents is described.
- Reddy, Nagireddy Veera,Kumar, Pailla Santhosh,Reddy, Peddi Sudhir,Kantam, Mannepalli Lakshmi,Reddy, Kallu Rajender
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supporting information
p. 805 - 809
(2015/02/19)
-
- Electronic Activity Tuning of Acyclic Guanidines for Lactide Polymerization
-
Novel aromatic guanidine-based organocatalysts for the ring-opening of l-lactide were synthesized and applied in comprehensive polymerization experiments and kinetic studies. The introduction of electronically active substituents led to a significant chan
- Eisenreich, Fabian,Viehmann, Philipp,Müller, Fabian,Hecht, Stefan
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p. 8729 - 8732
(2016/01/26)
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- Synthesis of unsymmetrical ureas and S-thiocarbamates under catalyst-free conditions in a [BMIM]BF4 ionic liquid
-
Unsymmetrical ureas and Sthiocarbamates were prepared in good to excellent yields by direct condensation of phenylurea with amines and thiols in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) without the addition of any additives. The [BMIM]BF4 ionic liquid is a mild medium and can be recycled and reused several times.
- Hosseinzadeh, Rahman,Tajbakhsh, Mahmood,Aghili, Nora
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p. 175 - 182
(2015/05/27)
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- A synthetic approach to N -aryl carbamates via copper-catalyzed Chan-Lam coupling at room temperature
-
A mild and efficient synthesis of N-arylcarbamates was achieved by reacting azidoformates with boronic acids in the presence of 10 mol % of copper chloride catalyst. The reaction proceeds readily in an open flask at room temperature without additional base, ligand, or additive. Rapid access to urea analogues via a two-step one-pot procedure is enabled by reacting N-arylcarbamates with aluminum-amine complexes. In addition, among several boronic acid derivatives prepared, dimethylphenyl boronate was found to react rapidly in its reaction with benzyl azidoformate, invoking in situ generation of this species in the catalytic cycle.
- Moon, Soo-Yeon,Kim, U. Bin,Sung, Dan-Bi,Kim, Won-Suk
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p. 1856 - 1865
(2015/02/19)
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- An easy access to unsymmetrical ureas: A photocatalytic approach to the Lossen rearrangement
-
An efficient and operationally simple method for the synthesis of unsymmetrical ureas from various hydroxamic acids and amines has been developed. Plausibly, the protocol involves visible-light-initiated in situ formation of Vilsmeier-Haack reagent and COBr2 with CBr4 and a catalytic amount of DMF in the presence of Ru(bpy)3Cl2 as a photocatalyst to bring about the Lossen rearrangement at room temperature. the Partner Organisations 2014.
- Yadav, Arvind K.,Srivastava, Vishnu P.,Yadav, Lal Dhar S.
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p. 24498 - 24503
(2014/07/07)
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- The use of aqueous potassium dichloroiodate for the synthesis of ureas
-
We report a straightforward and efficient reaction protocol for the syntheses of substituted ureas via treatment of thioureas with aqueous potassium dichloroiodate (KICl2). By tuning the reaction condition, thioureas bearing activated N-aryl substituents may undergo either selective oxidation or sequential oxidation and iodination, forming iodoaryl ureas in the latter case.
- Viana, Gil Mendes,De Sequeira Aguiar, Lúcia Cruz,De Araújo Ferr?o, Jonas,Simas, Alessandro Bolis Costa,Vasconcelos, Marcela Guariento
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p. 936 - 940
(2013/03/13)
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- Synthesis of New 1,3,4-Thiadiazole Derivatives Containing of Morpholine Ring
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The synthesis of new of 1,3,4-thiadiazole derivatives containing of morpholine ring are investigated. In this study, the derivatives of naphthol, amine and phenol are reacted with 4-morpholine carbonyl chloride. Then, prepared solutions are added to diazo
- Hamidian,Afrooz,Fozooni
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p. 487 - 489
(2013/02/22)
-
- Design and synthesis of a photoswitchable guanidine catalyst
-
A novel design as well as a straight-forward synthesis for a photoswitchable guanidine catalyst is reported. Intense studies of the photochromic properties demonstrated the reversible switchability of its photosensitive azobenzene moiety. Its activity in
- Viehmann, Philipp,Hecht, Stefan
-
supporting information
p. 1825 - 1830,6
(2020/09/16)
-
- Parallel synthesis of ureas and carbamates from amines and CO2 under mild conditions
-
"Chemical Equation Presented" A mild and efficient library synthesis technique has been developed for the synthesis of ureas and carbamates from carbamic acids derived from the DBU-catalyzed reaction of amines and gaseous carbon dioxide. Carbamic acids derived from primary amines reacted with Mitsunobu reagents to generate isocyanates in situ which were condensed with primary and secondary amines to afford the desired ureas. Similarly, carbamic acids from secondary amines reacted with alcohols activated with Mitsunobu reagents to form carbamates.
- Peterson, Scott L.,Stucka, Sabrina M.,Dinsmore, Christopher J.
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supporting information; experimental part
p. 1340 - 1343
(2010/06/15)
-
- Straightforward carbamoylation of nucleophilic compounds employing organic azides, phosphines, and aqueous trialkylammonium hydrogen carbonate
-
In the presence of aqueous trialkylammonium hydrogen carbonate, the Staudinger reaction leads to the intermediate formation of the corresponding isocyanate, which, in turn, reacts further with a nucleophilic reagent also present in the mixture and results in carbamoylation with good yield. On the basis of this reaction a practical carbamoylation procedure was devised and a comparative study on suitability of different solvents and phosphorus (III) derivatives for carbamoylation reaction was conducted. The versatility of the method was demonstrated by examples with different classes of nucleophilic compounds that included the aminomethyl resin and natural compounds that display poor solubility in organic solvents.
- Yagodkin, Andrey,L?schcke, Kerstin,Weisell, Janne,Azhayev, Alex
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experimental part
p. 2210 - 2221
(2010/04/29)
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- Acetoacetanilides as masked isocyanates: Facile and efficient synthesis of unsymmetrically substituted ureas
-
Figure Presented. A general and practical method for the preparation of unsymmetrically substituted ureas has been developed. By the reactions of acetoacetanilides with various amines including primary/secondary amines, a series of substituted aryl ureas were achieved in high yields. Acetoacetanilide substrates can be considered as masked reagents that liberate reactive isocyanates in situ.
- Wei, Ying,Liu, Jing,Lin, Shaoxia,Ding, Hongqian,Liang, Fushun,Zhao, Baozhong
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supporting information; experimental part
p. 4220 - 4223
(2010/11/04)
-
- Synthesis of some N-alkyl substituted urea derivatives as antibacterial and antifungal agents
-
A series of N-alkyl substituted urea derivatives were synthesized and evaluated for their in vitro antibacterial and antifungal activities. The N-alkyl substituted urea derivatives bearing morpholine moiety (3a-3k) showed better activities than those bearing diethylamine moiety (2a-2f). Compounds having fluoro substituent at ortho (3c) and para (3b) positions of the phenyl ring exhibited potent antimicrobial activities against Gram-positive and Gram-negative bacteria as well as fungi.
- Zheng, Qing-Zhong,Cheng, Kui,Zhang, Xiao-Min,Liu, Kai,Jiao, Qing-Cai,Zhu, Hai-Liang
-
experimental part
p. 3207 - 3212
(2010/08/20)
-
- Phenyl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylate as carbonyl source: Facile and selective synthesis of carbamates and ureas under mild conditions
-
The selective syntheses of carbamates, symmetric -ureas, and unsymmetrical ureas have been accomplished by the -reaction of amines with phenyl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylate as a carbonyl source under mild conditions. It is noteworthy that this process is mild, economic, and convenient.
- Lee, Hyung-Geun,Kim, Min-Jung,Park, Song-Eun,Kim, Jeum-Jong,Kim, Bo Ram,Lee, Sang-Gyeong,Yoon, Yong-Jin
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experimental part
p. 2809 - 2814
(2010/03/03)
-
- Carbonyldiimidazole-mediated lossen rearrangement
-
[Chemical Equation Presented] Carbonyldiimidazole (CDI) was found to mediate the Lossen rearrangement of various hydroxamic acids to isocyanates. This process is experimentally simple and mild, with imidazole and CO 2 being the sole stoichiometric byproduct. Significant for large-scale application, the method avoids the use of hazardous reagents and thus represents a green alternative to standard processing conditions for the Curtius and Hofmann rearrangements.
- Dube, Pascal,Fine Nathel, Noah F.,Vetelino, Michael,Couturier, Michel,Aboussafy, Claude Larrivee,Pichette, Simon,Jorgensen, Matthew L.,Hardink, Mark
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supporting information; scheme or table
p. 5622 - 5625
(2010/03/02)
-
- Synthesis of unsymmetrical ureas by sulfur-assisted carbonylation with carbon monoxide and oxidation with molecular oxygen under mild conditions
-
With ambient pressure of carbon monoxide and oxygen at room temperature, N,N-dialkyl-N′-arylureas were selectively accessible from secondary amines, aromatic amines, and sulfur in good to excellent yields. For example, N-butyl-N-methyl-N′-(3,4-dichlorophenyl)urea, which is used as a herbicide (neburon), was afforded successfully from butylmethylamine (2 equiv), 3,4-dichloroaniline (1 equiv) and sulfur (1 equiv) in 79% (21.8 g) yield using carbon monoxide (0.1 MPa) and oxygen (0.1 MPa) at 20°C in DMF. Georg Thieme Verlag Stuttgart.
- Mizuno, Takumi,Nakai, Takeo,Mihara, Masatoshi
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experimental part
p. 2492 - 2496
(2009/12/08)
-
- Distinct reactivity of Pd(OTs)2: The intermolecular Pd(II)-catalyzed 1,2-carboamination of dienes
-
A Pd-catalyzed intermolecular 1,2-carboamination route to indolines from N-aryl ureas and 1,3-dienes that proceeds under mild conditions in relatively nonacidic media, is presented. The in situ generation, or preformation, of a palladium tosylate emerges as a key parameter in gaining the requisite reactivity for the C-H insertion/carbopalladation/nucleophilic displacement process. Copyright
- Houlden, Chris E.,Bailey, Chris D.,Ford, J. Gair,Gagne, Michel R.,Lloyd-Jones, Guy C.,Booker-Milburn, Kevin I.
-
supporting information; experimental part
p. 10066 - 10067
(2009/02/04)
-
- N-Perfluoroalkylsulfonylimido derivatives of arenecarboxylic acid amides and their oxidative aza Hofmann rearrangement
-
The analogues of carboxamides in which the sp2-hybridized oxygen atom is replaced by more electron-withdrawing groups, {double bond, long}NSO2CF3 and {double bond, long}NSO2C4F9, have been
- Yagupolskii, Lev M.,Maletina, Irina I.,Sokolenko, Liubov V.,Vlasenko, Yurii G.,Buth, Sergey A.
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p. 486 - 492
(2008/12/23)
-
- Thiol on silica as a 'catch and release' support for isocyanates to afford ureas
-
Silica-bound thiocarbamates were prepared by Curtius rearrangement of carboxylic acids in the presence of thiol on silica gel. The solid supported thiocarbamates were found to be stable isocyanate equivalents, which upon treatment with amines efficiently afforded di- and tri-substituted ureas. The urea products released from the catch and release support were, in the majority of cases, greater than 95% pure and required no further work up.
- Bolshan, Yuri,Tomaszewski, Miroslaw J.,Santhakumar, Vijayaratnam
-
p. 4925 - 4927
(2008/02/08)
-
- Practical synthesis of unsymmetrical ureas from isopropenyl carbamates
-
A very convenient method for the synthesis of unsymmetrical ureas is described, based on isopropenyl carbamates. The synthetic efficiency of traditional methods for urea formation, such as use of phosgene or alkyl and aryl carbamates, is limited by the fo
- Gallou, Isabelle,Eriksson, Magnus,Zeng, Xingzhong,Senanayake, Chris,Farina, Vittorio
-
p. 6960 - 6963
(2007/10/03)
-
- Efficient Synthesis of Polysubstituted Acylguanidines and Guanylureas
-
(Benzotriazol-1-yl)carboximidamides were applied for the preparation of polysubstituted acylguanidines and guanylureas. The reaction sequence utilized mild conditions and gave high yields for final compounds and intermediates. The protocol developed allows for variation of the substituents at all positions of the products.
- Katritzky, Alan R.,Rogovoy, Boris V.,Cai, Xiaohong,Kirichenko, Nataliya,Kovalenko, Katherine V.
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p. 309 - 313
(2007/10/03)
-
- Efficient synthesis of ureas by direct palladium-catalyzed oxidative carbonylation of amines
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A general synthesis of symmetrically disubstituted ureas and trisubstituted ureas by direct Pd-catalyzed oxidative carbonylation of primary amines or of a mixture of a primary and a secondary amine, respectively, with unprecedented catalytic efficiencies for this kind of process, is reported. Reactions are carried out at 90-100 °C in DME as the solvent in the presence of PdI 2 in conjunction with an excess of KI as the catalytic system and under 20 atm of a 4:1 mixture of CO and air. In some cases, working in the presence of an excess of CO2 (40 atm) in addition to CO and air (60 atm total) had a beneficial effect on substrate reactivity and product yield. Cyclic five-membered and six-membered ureas were easily formed from primary diamines. The methodology has been successfully applied to the synthesis of pharmacologically active ureas, such as those deriving from α-amino esters or urea NPY5RA-972, a potent antagonist of the neuropeptide Y5 receptor.
- Gabriele, Bartolo,Salerno, Giuseppe,Mancuso, Raffaella,Costa, Mirco
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p. 4741 - 4750
(2007/10/03)
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- Mechanism of catalysis of the hydrolysis of a formamidinium compound
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The hydrolysis of a fluoroformamidinium ion to give a urea is subject to general base catalysis, where the addition of water is catalyzed by carboxylate monoanions (pKa 2.22-5.52) with a Bronsted coefficient of β = 0.80 through a class n mechan
- Dalby, Kevin N.
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p. 1961 - 1967
(2007/10/03)
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- One-Pot Reactions of N-(Mesyloxy)phthalimides with Secondary Amines to 2-Ureidobenzamides, 2-Ureidobenzoic Acids, Ethyl 2-Ureidobenzoates, or Isatoic Anhydrides
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The reaction of N-(mesyloxy)phthalimides with secondary amines was examined. Transformations are accomplished by one-pot reactions to optionally afford corresponding 2-ureidobenzamides, 2-ureidobenzoic acids, ethyl 2-ureidobenzoates, or isatoic anhydrides, respectively. The mechanism of the acid-catalyzed hydrolysis (or alcoholysis) of intermediate 2-ureidobenzamides to 2-ureidobenzoic acids (or esters) is discussed. A proton transfer mechanism involving the ureido moiety as an internal acid catalyst is proposed. Intermediate 2-ureidobenzoic acids undergo a further transformation to isatoic anhydrides. The utilization of the obtained 2-ureidobenzamides, 2-ureidobenzoic acids, and ethyl 2-ureidobenzoates to prepare 3,1-benzoxazin-4-ones is demonstrated.
- Guetschow, Michael
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p. 5109 - 5115
(2007/10/03)
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- A novel synthesis of isocyanates and ureas via β-elimination of haloform
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A novel synthesis of isocyanates via base-induced β-elimination of haloform from N-monosubstituted trihaloacetamides is described. The rate of reaction exhibits a strong dependence on the nature of the trihalomethyl group. Thus, while the reaction of tribromoacetamides proceeds at room temperature and the reaction of trichloroacetamides requires heating in polar solvents, no reaction could be observed for any of the corresponding trifluoro derivatives. This novel β-elimination of haloform from stable and readily available trihaloacetamides was applied to a 'one-pot' synthesis of ureas which avoids the use of phosgene and isolation of isocyanates.
- Braverman,Cherkinsky,Kedrova,Reiselman
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p. 3235 - 3238
(2007/10/03)
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- Selenium-catalyzed reductive carbonylation of nitrobenzene with amines as coreagents to give unsymmetric phenylureas
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The reductive carbonylation of nitrobenzene catalyzed by selenium to yield unsymmetric phenylureas has been studied. When secondary amines were used as coreagents, a single product, PhNHCONR2, was formed; when primary amines were chosen as coreagents, mixed products, including RNHCONHR, RNHCONHPh and PhNHCONHPh, were obtained.
- Yang, Ying,Lu, Shiwei
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p. 4845 - 4846
(2007/10/03)
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- The Introduction of Nitrile-Groups into Heterocycles and Concversion of Carboxylic Groups into their Corresponding Nitriles with Clorosulfonylisocyanate and Triethylamine
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Addition of chlorosulfonylisocyanate (CSI) to heterocycles such as thiophene (4) or indole (15) and unsaturated systems such as dihydropyran (7) gives N-chlorosulfonylamides RCONHSO2Cl, which can be converted by equivalent amounts of triethylamine to their corresponding nitriles.Since carboxylic acids react with CSI to N-chlorosulfonylamides, subsequent treatment with triethylamine affords the corresponding nitriles, but no isocyanates as claimed by other authors.The mechanisms of the conversion of the intermediate N-chlorosulfonylamides into the corresponding nitriles are discussed.
- Vorbrueggen, Helmut,Krolikiewicz, Konrad
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p. 6549 - 6558
(2007/10/02)
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