85600-10-8Relevant academic research and scientific papers
Hindered urea bond: A bilaterally responsive chemistry to hydrogen peroxide
Ying, Hanze,Yang, Yingfeng,Cai, Kaimin,Cheng, Jianjun
supporting information, p. 728 - 731 (2019/01/24)
As a type of safe, clean, and bio-relevant oxidant, hydrogen peroxide has been widely used as a trigger in the design of stimuli-responsive materials. Hindered urea bond (HUB) is a type of dynamic covalent bond which can reversibly dissociate into isocyanate and amine. Quenching of isocyanate or amine will shift the equilibrium and facilitate the degradation of HUB bond. Herein, we report that one of the HUB moiety – 1,1-tert-butylethylurea (TBEU) can react with hydrogen peroxide (H2O2) resulting in two opposing outcomes. Perhydrolysis of isocyanate and oxidation of amine lead to the bond fracture, while formation of urethane product with an oxygen inserted into the original TBEU structure was also observed giving a stabilized form of linkage. More precise kinetic control of the two distinct pathways are expected to make hydrogen peroxide a trigger to either degrade or fix the HUB based polymeric materials.
Green radicals of potassium poly(heptazine imide) using light and benzylamine
Markushyna, Yevheniia,Lamagni, Paolo,Teutloff, Christian,Catalano, Jacopo,Lock, Nina,Zhang, Guigang,Antonietti, Markus,Savateev, Aleksandr
supporting information, p. 24771 - 24775 (2019/11/14)
Tinted long-lived ionic carbon nitride radicals were recently introduced and applied in photocatalysis and energy storage. However, the reason for their higher activity in the photocatalytic reaction and optimal conditions for generating such radicals remain vague. Herein, we study the conditions for carbon nitride photocharging to achieve a higher charge density and validate a convenient method to quantify the number of electrons accumulated in carbon nitride semiconductors by quenching its radicals with methylviologen in the dark. In the presence of CO2, potassium poly(heptazine imide) (K-PHI) can be charged by up to 1000 μmol of electrons per gram of the material using benzylamine as an electron donor. Under the same conditions, mesoporous graphitic carbon nitride can accumulate only 50 μmol of electrons per gram. The products of the benzylamine oxidative coupling are imine and ammonia.
First catalyst-free CO2 trapping of: N -acyliminium ions under ambient conditions: Sustainable multicomponent synthesis of thia- and oxazolidinyl carbamates
Franz, Max,Martens, Jürgen,Stalling, Timo,Steinert, Henning
, p. 6914 - 6926 (2018/10/02)
The first trapping of N-acyliminium ions by in situ generated carbaminic acid (product of carbon dioxide (CO2) and amine) is reported. This catalyst-free reaction provides a convenient and feasible approach to prepare N-acyl thia- and oxazolidi
A high-yielding, expeditious, and multicomponent synthesis of urea and carbamate derivatives by using triphenylphosphine/trichloroisocyanuric acid system
Ghodsinia, Sara S.E.,Akhlaghinia, Batool
, p. 104 - 110 (2016/01/25)
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.
Parallel synthesis of ureas and carbamates from amines and CO2 under mild conditions
Peterson, Scott L.,Stucka, Sabrina M.,Dinsmore, Christopher J.
supporting information; experimental part, p. 1340 - 1343 (2010/06/15)
"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.
Mild and convenient synthesis of organic carbamates from amines and carbon dioxide using tetraethylammonium superoxide
Singh, Krishna Nand
, p. 2651 - 2654 (2008/02/12)
A safe and simple method of preparing organic carbamates has been achieved from amines and carbon dioxide using tetraethylammonium superoxide generated in situ. Copyright Taylor & Francis Group, LLC.
Role of the macrocyclic polyether in the synthesis of N-alkylcarbamate ester from primary amines, CO2 and alkyl halides in the presence of crown-ethers
Aresta,Quaranta
, p. 1515 - 1530 (2007/10/02)
Primary amines, RNH2 1, and CO2 easily afford monoalkylammonium N-alkylcarbamates, [RNH3][O2CNHR] 2, that have been reacted with alkyl halides, R'X, in the presence of crown-ethers to give organic carbamates in good yield. We report here the synthesis and spectroscopic characterization of some alkylammonium carbamates 2, where R - benzyl 2a, allyl 2b, ter-butyl 2c, cyclohexyl 2d, and discuss their stability in solution and the conditions in which they can react with alkyl halides to give organic carbamates, RNHC(O)OR'. The role played by the macrocyclic ligand in modifying the reactivity of monoalkylammonium carbamates 2 towards R'X has been rationalized and the influence of parameters such as solvent, temperature and CO2 pressure on the yield and selectivity of the process leading to organic carbamates has been also settled.
