6938-45-0Relevant academic research and scientific papers
Heterogeneous Metal–Organic-Framework-Based Biohybrid Catalysts for Cascade Reactions in Organic Solvent
Wang, Yangxin,Zhang, Ningning,Zhang, En,Han, Yunhu,Qi, Zhenhui,Ansorge-Schumacher, Marion B.,Ge, Yan,Wu, Changzhu
, p. 1716 - 1721 (2019)
In cooperative catalysis, the combination of chemo- and biocatalysts to perform one-pot reactions is a powerful tool for the improvement of chemical synthesis. Herein, UiO-66-NH2 was employed to stepwise immobilize Pd nanoparticles (NPs) and Candida antarctica lipase B (CalB) for the fabrication of biohybrid catalysts for cascade reactions. Distinct from traditional materials, UiO-66-NH2 has a robust but tunable structure that can be utilized with a ligand exchange approach to adjust its hydrophobicity, resulting in excellent catalyst dispersity in diverse reaction media. These attractive properties contribute to the formation of MOF-based biohybrid catalysts with high activity and selectivity in the synthesis of benzyl hexanoate from benzaldehyde and ethyl hexanoate. With this proof-of-concept, we reasonably expect that future tailor-made MOFs can combine other catalysts, ranging from chemical to biological catalysts for applications in industry.
Hierarchically structured Beta zeolites with intercrystal mesopores and the improved catalytic properties
Liu, Baoyu,Zheng, Liming,Zhu, Zhihong,Li, Chao,Xi, Hongxia,Qian, Yu
, p. 412 - 419 (2014)
Hierarchical Beta zeolite with mesoporous/microporous structure was synthesized by employing a bifunctionalized amphiphilic surfactant. N 2 adsorption-desorption isotherms indicated the presence of hierarchical mesopores in this sample. Transmission electron microscopy images confirmed the co-presence of ordered micropores and hierarchical mesopores. This sample exhibited excellent hydrothermal stability. In addition, the prepared hierarchically structured Beta zeolite showed greatly enhanced catalytic activity as compared with conventional counterpart for probe reaction involving large molecules due to the highly mesoporous structure, in which diffusion constraints of reactant molecules are the main concern. Such hierarchical micro/mesostructure Beta zeolite combined good hydrothermal stability and high activities may find potential applications in catalysis and adsorption involving bulky molecules.
Fully recyclable Br?nsted acid catalyst systems
Watson, Christopher B.,Kuechle, Adrianna,Bergbreiter, David E.
, p. 1266 - 1273 (2021/02/26)
Homogeneous and heterogeneous sulfonic acid catalysts are some of the most common catalysts used in organic chemistry. This work explores an alternative scheme using a fully recyclable polymeric solvent (a poly-α-olefin (PAO)) and soluble PAO-anchored polyisobutylene (PIB)-bound sulfonic acid catalysts. This PAO solvent is nonvolatile and helps to exclude water by its nonpolar nature which in turn drives reactions without the need for distillation of water, avoiding the need for excess reagents. This highly nonpolar solvent system uses polyisobutylene (PIB) bound sulfonic acid catalysts that are phase-anchored in solvents like PAO. The effectivenes of these catalysts was demonstrated by their use in esterifications, acetalizations, and multicomponent condensations. These catalysts and the PAO solvent phase show excellent recyclability in schemes where products are efficiently separated. For example, this non-volatile polymeric solvent and the PIB-bound catalyst can be recycled quantitatively when volatile products are separated and purified by distillation. In other cases, product purification can be effected by product self-separation or by extraction.
Carboxylic Acid Reductase Can Catalyze Ester Synthesis in Aqueous Environments
Pongpamorn, Pornkanok,Kiattisewee, Cholpisit,Kittipanukul, Narongyot,Jaroensuk, Juthamas,Trisrivirat, Duangthip,Maenpuen, Somchart,Chaiyen, Pimchai
supporting information, p. 5749 - 5753 (2021/02/01)
Most of the well-known enzymes catalyzing esterification require the minimization of water or activated substrates for activity. This work reports a new reaction catalyzed by carboxylic acid reductase (CAR), an enzyme known to transform a broad spectrum of carboxylic acids into aldehydes, with the use of ATP, Mg2+, and NADPH as co-substrates. When NADPH was replaced by a nucleophilic alcohol, CAR from Mycobacterium marinum can catalyze esterification under aqueous conditions at room temperature. Addition of imidazole, especially at pH 10.0, significantly enhanced ester production. In comparison to other esterification enzymes such as acyltransferase and lipase, CAR gave higher esterification yields in direct esterification under aqueous conditions. The scalability of CAR catalyzed esterification was demonstrated for the synthesis of cinoxate, an active ingredient in sunscreen. The CAR esterification offers a new method for green esterification under high water content conditions.
Membrane transport inspired hydrolysis of non-activated esters at near physiological pH
Mandal, Raki,Mahanty, Kingshuk,Mandal, Subhendu,De Sarkar, Suman,Tarafdar, Pradip K.
supporting information, p. 11088 - 11091 (2021/10/30)
A positively charged micelle loaded with substrates was transported selectively to the reaction site (cathode) to promote the proximity and localization of the reactants (ester and hydroxide). The guided vehicular delivery coupled with electrolysis allows the hydrolysis of non-activated esters at near physiological pH with significant yields along with recyclability.
Environmentally benign decarboxylative: N-, O-, and S-Acetylations and acylations
Ghosh, Santanu,Purkait, Anisha,Jana, Chandan K.
supporting information, p. 8721 - 8727 (2020/12/30)
An operationally simple and general method for acetylation and acylation of a wide variety of substrates (amines, alcohols, phenols, thiols, and hydrazones) has been reported. Meldrum's acid and its derivatives have been used as an air-stable, non-volatile, cost-effective, and easy to handle acetylating/acylating agent. Easily separable byproducts (CO2 and acetone) allowed the isolation of analytically pure acetylated products without the requirement of work-up and any chromatography. This journal is
Method for hydrogenolysis of halides
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, (2021/01/11)
The invention discloses a method for hydrogenolysis of halides. The invention discloses a preparation method of a compound represented by a formula I. The preparation method comprises the following step: in a polar aprotic solvent, zinc, H2O and a compound represented by a formula II are subjected to a reaction as shown in the specification, wherein X is halogen; Y is -CHRR or R; hydrogenin H2O exists in the form of natural abundance or non-natural abundance. According to the preparation method, halide hydrogenolysis can be simply, conveniently and efficiently achieved through a simple and mild reaction system, and good functional group compatibility and substrate universality are achieved.
An effective cis-β-octahedral Mn(iii) SALPN catalyst for the Mukaiyama-Isayama hydration of α,β-unsaturated esters
Donnelly, Paul S.,North, Andrea J.,Radjah, Natalia Caren,Ricca, Michael,Robertson, Angus,White, Jonathan M.,Rizzacasa, Mark A.
supporting information, p. 7699 - 7702 (2019/07/09)
Two cis-β-MnIIISALPN catalysts were synthesised and tested in the Mukaiyama-Isayama hydration of α,β-unsaturated esters. The MnIIIEtOSALPN(acac) complex 7 is the most active and catalyses hydration with little or no detectable undesired alkene reduction. This catalyst is superior for alkene hydration compared to the originally reported Mn(dpm)3 catalyst.
Dehalogenative Deuteration of Unactivated Alkyl Halides Using D2O as the Deuterium Source
Xia, Aiyou,Xie, Xin,Hu, Xiaoping,Xu, Wei,Liu, Yuanhong
, p. 13841 - 13857 (2019/10/17)
The general dehalogenation of alkyl halides with zinc using D2O or H2O as a deuterium or hydrogen donor has been developed. The method provides an efficient and economic protocol for deuterium-labeled derivatives with a wide substrate scope under mild reaction conditions. Mechanistic studies indicated that a radical process is involved for the formation of organozinc intermediates. The facile hydrolysis of the organozinc intermediates provides the driving force for this transformation.
Formyloxyacetoxyphenylmethane and 1,1-diacylals as versatile O-formylating and O-acylating reagents for alcohols
Chapman, Robert S.L.,Francis, Molly,Lawrence, Ruth,Tibbetts, Joshua D.,Bull, Steven D.
, p. 6442 - 6452 (2018/10/02)
Formyloxyacetoxyphenylmethane, symmetric 1,1-diacylals and mixed 1-pivaloxy-1-acyloxy-1-phenylmethanes have been used as moisture stable O-formylating and O-acylating reagents for primary and secondary alcohols, allylic alcohols and phenols under solvent/catalyst free conditions to afford their corresponding esters in good yield.
