3083-88-3Relevant academic research and scientific papers
Lanthanum(III) Trifluoromethanesulfonate Catalyzed Direct Synthesis of Ureas from N-Benzyloxycarbonyl-, N -Allyloxycarbonyl-, and N -2,2,2-Trichloroethoxycarbonyl-Protected Amines
Bui, Tien Tan,Kim, Hee-Kwon
supporting information, p. 997 - 1002 (2020/06/17)
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.
A Fe3O4?SiO2/Schiff Base/Pd Complex as an Efficient Heterogeneous and Recyclable Nanocatalyst for One-Pot Domino Synthesis of Carbamates and Unsymmetrical Ureas
Inaloo, Iman Dindarloo,Majnooni, Sahar
, p. 6359 - 6368 (2019/11/05)
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.
Palladium-Catalyzed Synthesis of Symmetrical and Unsymmetrical Ureas Using Chromium Hexacarbonyl as a Convenient and Safe Alternative Carbonyl Source
Mozaffari, Mozhdeh,Nowrouzi, Najmeh
supporting information, p. 7541 - 7544 (2019/12/12)
Pd-catalyzed synthesis of urea derivatives from aryl iodides and different aliphatic and aromatic amines using sodium azide and chromium hexacarbonyl is described. In this process, carbonylation of aryl iodides, Curtius rearrangement of aroyl azides, and nucleophilic addition of amines sequentially occur to afford the products in good to excellent yields. This protocol is operationally simple and displays a broad substrates scope.
CaI2-Catalyzed direct transformation of: N -Alloc-, N -Troc-, and N -Cbz-protected amines to asymmetrical ureas
Tran, Van Hieu,Kim, Hee-Kwon
, p. 14093 - 14101 (2019/09/18)
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.
Metal-Free Synthesis of Unsymmetrical Ureas and Carbamates from CO2 and Amines via Isocyanate Intermediates
Ren, Yiming,Rousseaux, Sophie A. L.
, p. 913 - 920 (2018/01/28)
A mild and metal-free synthesis of aryl isocyanates from arylamines under an atmosphere of CO2 was developed. The carbamic acid intermediate, derived from the arylamine starting material and CO2 in the presence of DBU, is dehydrated by activated sulfonium reagents to generate the corresponding isocyanate. The latter can be detected by in situ IR and trapped by various amines and alcohols to make unsymmetrical ureas and carbamates, respectively. Dicarbamates can also be prepared in good yields via the mild dehydration of the corresponding dicarbamic acids.
Chloromethylated polystyrene immobilized ruthenium complex of 2-(2-pyridyl)benzimidazole catalyst for the synthesis of bioactive disubstituted ureas by carbonylation reaction
Dey, Tusar Kanto,Ghosh, Kajari,Basu, Priyanka,Molla, Rostam Ali,Islam, Sk. Manirul
, p. 9168 - 9176 (2018/06/08)
Polymer supported transition metal complex catalysts have numerous applications as heterogeneous catalysts due to their ease of synthesis and commercial availability. Ru-Py-Merf was synthesized by anchoring 2-(2-pyridyl)benzimidazole to the polymer matrix, followed by loading of ruthenium salt. This Ru-Py-Merf material was thoroughly characterized by FTIR spectroscopy, UV-vis absorption spectroscopy, FE-SEM analysis, EDAX analysis, CHN analysis, AAS spectroscopy and TGA. Ru-Py-Merf showed excellent catalytic activity in the synthesis of symmetric and asymmetric disubstituted ureas by reductive carbonylation of nitrobenzenes and anilines. The as-synthesized Ru-Py-Merf catalyst is entirely heterogeneous in nature, thermally stable and can be easily reused up to six times.
An efficient one-pot synthesis of N,N′-disubstituted phenylureas and N-aryl carbamates using hydroxylamine-O-sulfonic acid
Bao, Jennifer,Kuik, Dale,Tranmer, Geoffrey K.
supporting information, p. 5546 - 5553 (2018/06/12)
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.
Facile direct synthesis of unsymmetrical ureas from N-Alloc-, N-Cbz-, and N-Boc-protected amines using DABAL-Me3
Kang, Soosung,Kim, Hee-Kwon
, p. 4036 - 4046 (2018/06/13)
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.
Pd/C Catalyzed Carbonylation of Azides in the Presence of Amines
Zhao, Jin,Li, Zongyang,Yan, Shuaihu,Xu, Shiyang,Wang, Ming-An,Fu, Bin,Zhang, Zhenhua
supporting information, p. 1736 - 1739 (2016/05/19)
A facile and efficient Pd/C-catalyzed carbonylation of both aliphatic and aromatic azides in the presence of amines is reported. Serving as the widely existed fragments in an array of biological pharmaceuticals, functionalized unsymmetrical ureas were str
