94398-06-8Relevant academic research and scientific papers
An Improved Synthesis of Urea Derivatives from N -Acylbenzotriazole via Curtius Rearrangement
Agrahari, Anand K.,Singh, Anoop S.,Singh, Sumit K.,Tiwari, Vinod K.,Yadav, Mangal S.
, p. 3443 - 3450 (2019/09/07)
The good leaving tendency of the benzotriazole moiety has been exploited for the synthesis of symmetric, unsymmetric, N -acyl, and cyclic ureas in good yields from N -acylbenzotriazoles by treating the latter with various amines in the presence of TMSN 3 /Et 3 N in a sealed tube. The salient features of the devised protocol includes the high-yield, mild, metal-free, one-pot reaction conditions, and short reaction time. Furthermore, in many cases, no column chromatography is required for the purification.
Pd-Catalyzed Carbonylation of Acyl Azides
Chang, Wenxu,Fu, Bin,Huang, Baoliang,Jiao, Lei,Li, Zongyang,Wang, Peng,Xu, Shiyang,Yuan, Chenhui,Zhang, Zhenhua
, p. 9497 - 9508 (2019/08/26)
Pd-catalyzed reactions of azides with CO to access an isocynate intermediate have been developed extensively in recent years. However, the catalytic carbonylation of sensitive acyl azides has not been reported. Herein, we report a simple Pd-catalyzed carbonylation reaction of acyl azides with broad substrate scope, high efficiency, and simple operation under mild conditions, which provides facile access to acyl ureas. In addition, a mechanistic study was carried out by both experiment and DFT calculation. Control experiments and kinetic study revealed that the real active palladium species were Pd(0). The result of kinetic study suggested that palladium catalyst, azide, and CO were all involved in the turnover-limiting step except for amine. Further DFT study suggested that an unprecedented five-membered palladacycle intermediate was the key intermediate in the carbonylation reaction. ?
KINETICS AND MECHANISM OF METHANOLYSIS OF BENZOYL DERIVATIVES OF SUBSTITUTED PHENYLUREAS AND PHENYLTHIOUREAS
Kavalek, Jaromir,El Bahaie, Said,Sterba, Vojeslav
, p. 2103 - 2110 (2007/10/02)
The methanolysis rate constants and dissociation constants have been measured of benzoyl derivatives of substituted phenylureas and phenylthioureas.The dissociation constants of the thio derivatives are higher by 1 order of magnitude and the rate constants are higher by 2 orders of magnitude than the respective values of the oxygen analogues.Logarithms of the rate and dissociation constants have been correlated with Hammett ? constant; the ρ constant of the methanolysis of the oxygen derivatives is almost 2 * higher than that of the thio derivatives, which is explained by a change in the rate-limiting step.Methylation of the phenyl nitrogen atom increases the acidity by almost 2 orders of magnitude.This effect is due obviously to steric hindrance to the conjugation with the adjacent carbonyl or thiocarbonyl group.
