578-66-5Relevant articles and documents
Hydrazone Switch-Based Negative Feedback Loop
Pramanik, Susnata,Aprahamian, Ivan
, p. 15142 - 15145 (2016)
A negative feedback loop that relies on the coordination-coupled deprotonation (CCD) of a hydrazone switch has been developed. Above a particular threshold of zinc(II), CCD releases enough protons to the environment to trigger a cascade of reactions that yield an imine. This imine sequesters the excess of zinc(II) from the hydrazone switch, hence lowering the effective amount of protons, and switching the cascade reactions OFF , thus establishing the negative feedback loop.
Continuous and Selective Hydrogenation of Heterocyclic Nitroaromatics in a Micropacked Bed Reactor
Chen, Xingkun,Duan, Xiaonan,Wang, Xuepeng,Zhang, Jisong
, p. 2100 - 2109 (2021/09/08)
The hydrogenation of heterocyclic nitroaromatics is of great importance in the pharmaceutical industry for the synthesis of key intermediates. However, high selectivity is difficult to achieve in conventional batch reactors owing to severe back mixing and poor mass transfer performance, resulting in the high requirement for subsequent separation processes. In this work, a continuous flow system based on a micropacked bed reactor is developed for the selective hydrogenation of heterocyclic nitroaromatics and the reductions of 5-nitroisoquinoline to 5-aminoisoquinoline and 5-amino-1,2,3,4-tetrahydroisoquinoline are selected as the model reactions. With the optimal reaction conditions, maximal yields of 99.9% (5-aminoisoquinoline) and 99.3% (5-amino-1,2,3,4-tetrahydroisoquinoline) are obtained successfully. Moreover, this system exhibits remarkable performance for the selective hydrogenation of relevant heterocyclic nitroaromatics with all yields beyond the level of 97.5%. The continuous flow system enables efficient hydrogenation of heterocyclic nitroaromatics and remarkable selectivity of target products with shorter reaction time and safer operation compared with batch reactors.
Biorenewable carbon-supported Ru catalyst for: N -alkylation of amines with alcohols and selective hydrogenation of nitroarenes
Goyal, Vishakha,Narani, Anand,Natte, Kishore,Poddar, Mukesh Kumar,Ray, Anjan,Sarki, Naina,Tripathi, Deependra
, p. 14687 - 14694 (2021/08/23)
Herein, we developed a renewable carbon-supported Ru catalyst (Ru/PNC-700), which was facilely prepared via simple impregnation followed by the pyrolysis process. The prepared Ru/PNC-700 catalyst demonstrated remarkable catalytic activity in terms of conversion and selectivity towards N-alkylation of anilines with benzyl alcohol and chemoselective hydrogenation of aromatic nitro compounds. In addition, local anesthetic pharmaceutical agents (e.g., butamben and benzocaine), including key drug intermediates, were synthesized in excellent yields under mild conditions and in the presence of water as a green solvent. Moreover, the prepared Ru/PNC-700 catalyst could be easily recovered and reused up to five times without any apparent loss in activity and selectivity.
CoPd Nanoalloys with Metal–Organic Framework as Template for Both N-Doped Carbon and Cobalt Precursor: Efficient and Robust Catalysts for Hydrogenation Reactions
Zhu, Jie,Xu, Deng,Ding, Lu-jia,Wang, Peng-cheng
, p. 2707 - 2716 (2021/01/21)
In this work, a series of metal–organic framework (MOF)-derived CoPd nanoalloys have been prepared. The nanocatalysts exhibited excellent activities in the hydrogenation of nitroarenes and alkenes in green solvent (ethanol/water) under mild conditions (H2 balloon, room temperature). Using ZIF-67 as template for both carbon matrix and cobalt precursor coating with a mesoporous SiO2 layer, the catalyst CoPd/NC@SiO2 was smoothly constructed. Catalytic results revealed a synergistic effect between Co and Pd components in the hydrogenation process due to the enhanced electron density. The mesoporous SiO2 shell effectively prevented the sintering of hollow carbon and metal NPs at high temperature, furnishing the well-dispersed nanoalloy catalysts and better catalytic performance. Moreover, the catalyst was durable and showed negligible activity decay in recycling and scale-up experiments, providing a mild and highly efficient way to access amines and arenes.