1796-27-6Relevant articles and documents
Group 3 metal (Sc, La) triflates as catalysts for the carbomethoxylation of aliphatic amines with dimethylcarbonate under mild conditions
Distaso, Monica,Quaranta, Eugenio
, p. 1531 - 1539 (2004)
The activity of Sc(OTf)3 and La(OTf)3 (OTf=SO 3CF3) as catalysts for the phosgene-free synthesis of carbamate esters via carbomethoxylation of aliphatic amines with dimethylcarbonate (DMC) has been investigated. In the presence of M(OTf) 3 (M=Sc, La), primary and secondary aliphatic amines easily react with dimethylcarbonate, under very mild conditions (20°C), to afford carbamate esters with good yield and excellent selectivity (?100%). Sc(OTf)3 is a more effective catalyst than the homologue La salt. The carbomethoxylation reaction requires as strict anhydrous conditions, as, at 20°C, the presence of water inhibits markedly the catalytic activity of both triflate salts. Temperature influences carbamate selectivity, which is lower at higher temperature because of deleterious formation of N-methylation side-products.
Copper-Catalyzed Coupling of Amines with Carbazates: An Approach to Carbamates
Wang, Song-Ning,Zhang, Guo-Yu,Shoberu, Adedamola,Zou, Jian-Ping
, p. 9067 - 9075 (2021/07/19)
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.
Amine-Responsive Disassembly of AuI–CuI Double Salts for Oxidative Carbonylation
Cao, Yanwei,Yang, Jian-Gong,Deng, Yi,Wang, Shengchun,Liu, Qi,Shen, Chaoren,Lu, Wei,Che, Chi-Ming,Chen, Yong,He, Lin
supporting information, p. 2080 - 2084 (2019/12/24)
A sensitive amine-responsive disassembly of self-assembled AuI-CuI double salts was observed and its utilization for the synergistic catalysis was enlightened. Investigation of the disassembly of [Au(NHC)2][CuI2] revealed the contribution of Cu-assisted ligand exchange of N-heterocyclic carbene (NHC) by amine in [Au(NHC)2]+ and the capacity of [CuI2]? on the oxidative step. By integrating the implicative information coded in the responsive behavior and inherent catalytic functions of d10 metal complexes, a catalyst for the oxidative carbonylation of amines was developed. The advantages of this method were clearly reflected on mild reaction conditions and the significantly expanded scope (51 examples); both primary and steric secondary amines can be employed as substrates. The cooperative reactivity from Au and Cu centers, as an indispensable prerequisite for the excellent catalytic performance, was validated in the synthesis of (un)symmetric ureas and carbamates.
Electrochemical Functional-Group-Tolerant Shono-type Oxidation of Cyclic Carbamates Enabled by Aminoxyl Mediators
Wang, Fei,Rafiee, Mohammad,Stahl, Shannon S.
supporting information, p. 6686 - 6690 (2018/05/07)
An electrochemical method has been developed for α-oxygenations of cyclic carbamates by using a bicyclic aminoxyl as a mediator and water as the nucleophile. The mediated electrochemical process enables substrate oxygenation to proceed at a potential that is approximately 1 V lower than the redox potential of the carbamate substrate. This feature allows for functional-group compatibility that is inaccessible with conventional Shono oxidations, which proceed by direct electrochemical substrate oxidation. This reaction also represents the first α-functionalization of non-activated cyclic carbamates with oxoammonium oxidants.
Heterobimetallic dinuclear lanthanide alkoxide complexes as acid-base bifunctional catalysts for synthesis of carbamates under solvent-free conditions
Zeng, Ruijie,Bao, Linquan,Sheng, Hongting,Sun, Lili,Chen, Man,Feng, Yan,Zhu, Manzhou
, p. 78576 - 78584 (2016/09/09)
Heterobimetallic dinuclear lanthanide alkoxide complexes Ln2Na8(OCH2CH2NMe2)12(OH)2 [Ln: I (Nd), II (Sm), III (Yb) and IV (Y)] were used as efficient acid-base bifunctional catalysts for the synthesis of carbamates from dialkyl carbonates and amines as well as the N-Boc protection of amines. The cooperative catalysts showed high catalytic activity and a wide scope of substrates with good to excellent yields under solvent-free conditions. The systems have shown higher catalytic activities due to the noteworthy synergistic interactions of Lewis acid center-Br?nsted basic center. The comparison of catalytic efficiency between mono- and dinuclear heterobimetallic lanthanide alkoxide analogues was also investigated.
L-Proline-TBAB-catalyzed phosgene free synthesis of methyl carbamates from amines and dimethyl carbonate
Kumar, Subodh,Jain, Suman L.
, p. 2935 - 2938 (2013/09/12)
The reaction of amines and dimethyl carbonate (DMC) in the presence of catalytic amounts of l-proline and tetrabutylammonium bromide (TBAB) afforded methyl carbamates in good to excellent yields under mild conditions. The presence of both l-proline and TBAB co-catalysts is vital for this transformation.
Nitrogen-containing organobases as promoters in the cobalt(II)-Schiff base catalyzed oxidative carbonylation of amines
Saliu, Francesco,Putomatti, Benedetto,Rindone, Bruno
scheme or table, p. 3590 - 3593 (2012/09/08)
The use of organic bases as promoters in the cobalt(II)-Schiff base complex catalyzed oxidative carbonylation of amines was investigated. The generality of the reaction was also studied by submitting different amines to the same procedure and by changing the reaction conditions. Very good yields in the corresponding ureas were achieved in toluene with a catalyst loading of 0.5 mol % and using TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene) as promoter. Methyl carbamates were obtained in methanol.
Photochemical rearrangement of N-mesyloxylactams: Stereospecific formation of N-heterocycles
Drouin, Alexandre,Winter, Dana K.,Pichette, Simon,Aubert-Nicol, Samuel,Lessard, Jean,Spino, Claude
, p. 164 - 169 (2011/03/19)
N-Mesyloxylactams undergo an efficient ring-contraction to N-heterocycles of various ring sizes. Yields increase with the degree of substitution α to the carbonyl. The stereochemical information of a chiral migrating carbon is conserved making this reacti
Carbamate synthesis from amines and dialkyl carbonate over inexpensive and clean acidic catalyst-Sulfamic acid
Wang, Bo,He, Jing,Sun, Run Cang
scheme or table, p. 794 - 797 (2011/11/13)
Sulfamic acid has been proved to be the most efficient and recyclable catalyst in carbamate synthesis from alkylamine and dialkyl carbonate. High selectivity, cost-efficiency and simple product separation were the advantageous features obtained in this process. Sulfamic acid could be reused several times and keep its initial activity in the recycle runs. In addition, sulfamic acid has also exhibited the potential catalytic ability for alkylation of aromatic amines.
Indium-catalyzed reaction for the synthesis of carbamates and carbonates: selective protection of amino groups
Kim, Joong-Gon,Jang, Doo Ok
experimental part, p. 2688 - 2692 (2009/08/09)
We developed a simple, efficient, and selective method for preparing organic carbamates and carbonates using a catalytic amount of indium. A wide range of carbamates and carbonates were synthesized in high yields. The method is also applicable to the selective protection of amino groups under mild conditions.
