61655-07-0Relevant academic research and scientific papers
UiO-type metal-organic frameworks with NHC or metal-NHC functionalities for: N-methylation using CO2 as the carbon source
Zhang, Xu,Jiang, Yilin,Fei, Honghan
supporting information, p. 11928 - 11931 (2019/10/11)
We demonstrate the first metal-organic framework (MOF) that catalyzes N-methylation of amines using 1 atm CO2 and phenylsilane under ambient conditions. Compared with its homogeneous analog, the incorporation of N-heterocyclic carbene (NHC) into the MOF provides more efficient catalysis with improved reaction kinetics, turnover numbers and recyclability. Moreover, the metalated NHC functionalized MOF achieves direct N-methylation of amines bearing carboxylate moieties, which are common building blocks in pharmaceutical chemistry.
Cooperative Catalytic Activation of Si?H Bonds: CO2-Based Synthesis of Formamides from Amines and Hydrosilanes under Mild Conditions
Luo, Rongchang,Lin, Xiaowei,Chen, Yaju,Zhang, Wuying,Zhou, Xiantai,Ji, Hongbing
, p. 1224 - 1232 (2017/03/29)
A simple cooperative catalytic system was successfully developed for the solvent-free N-formylation of amines with CO2 and hydrosilanes under ambient conditions, which was composed of a Zn(salen) catalyst and quaternary ammonium salt. These commercially available binary components activated the Si?H bonds effectively, owing to the intermolecular synergistic effect between Lewis base and transition metal center (LB–TM), and subsequently facilitated the insertion of CO2 to form the active silyl formats, thereby leading to excellent catalytic performance at a low catalyst loading. Furthermore, the bifunctional Zn(salen) complexes, with two imidazolium-based ionic-liquid (IL) units at the 3,3′-position of salen ligand, acted as intramolecularly cooperative catalysts, and the solvent-regulated separation resulted in facile catalyst recycling and reuse.
N-dealkylation of an N-cyclopropylamine by horseradish peroxidase. Fate of the cyclopropyl group
Shaffer,Morton,Hanzlik
, p. 8502 - 8508 (2007/10/03)
Cyclopropylamines inactivate cytochrome P450 enzymes which catalyze their oxidative N-dealkylation. A key intermediate in both processes is postulated to be a highly reactive aminium cation radical formed by single electron transfer (SET) oxidation of the nitrogen center, but direct evidence for this has remained elusive. To address this deficiency and identify the fate of the cyclopropyl group lost upon N-dealkylation, we have investigated the oxidation of N-cyclopropyl-N-methylaniline (3) by horseradish peroxidase, a well-known SET enzyme. For comparison, similar studies were carried out in parallel with N-isopropyl-N-methylaniline (9) and N,N-dimethylaniline (8). Under standard peroxidatic conditions (HRP, H2O2, air), HRP oxidizes 8 completely to N-methylaniline (4) plus formaldehyde within 15-30 min, whereas 9 is oxidized more slowly (14C]-3, [1′-13C]-3, and [2′,3′-13C]-3 as substrates, radiochemical and NMR analyses of incubation mixtures revealed that the complete oxidation of 3 by HRP yields 4 (0.2 mol), β-hydroxypropionic acid (17, 0.2 mol), and N-methylquinolinium (16, 0.8 mol). In buffer purged with pure O2, the complete oxidation of 3 yields 4 (0.7 mol), 17 (0.7 mol), and 16 (0.3 mol), while under anaerobic conditions, 16 is formed quantitatively from 3. These results indicate that the aminium ion formed by SET oxidation of 3 undergoes cyclopropyl ring fragmentation exclusively to generate a distonic cation radical (14+?) which then partitions between unimolecular cyclization (leading, after further oxidation, to 16) and bimolecular reaction with dissolved oxygen (leading to 4 and 17 in a 1:1 ratio). Neither β-hydroxypropionaldehyde, acrolein, nor cyclopropanone hydrate are formed as SET metabolites of 3. The synthetic and analytical methods developed in the course of these studies should facilitate the application of cyclopropylamine-containing probes to reactions catalyzed by cytochrome P450 enzymes.
