93-09-4Relevant articles and documents
Metal-Free Solvent/Base-Switchable Divergent Synthesis of Multisubstituted Dihydrofurans
Gore, Babasaheb Sopan,Kuo, Chiao-Ying,Garkhedkar, Amol Milind,Chang, Yu-Lun,Wang, Jeh-Jeng
, p. 6160 - 6165 (2020)
A general protocol for the synthesis of multisubstituted 2,3-dihydrofuran-2-carbonitriles and 4,5-dihydrofuran-3-carbonitriles was demonstrated under a metal-free regime with the same oxidant, TBHP. By simply switching the reaction solvent and base, the reaction proceeds via two pathways. An unexpected -CN group migration rearrangement and hydroxylation have occurred in nonpolar and polar solvents, respectively, under the reported conditions. Furthermore, the source of the hydroxyl group and hydrogen in the reaction is indirectly confirmed with isotope labeling studies.
Gram-scale synthesis of carboxylic acids via catalytic acceptorless dehydrogenative coupling of alcohols and hydroxides at an ultralow Ru loading
Chen, Cheng,Cheng, Hua,Verpoort, Francis,Wang, Zhi-Qin,Wu, Zhe,Yuan, Ye,Zheng, Zhong-Hui
, (2021/12/13)
Acceptorless dehydrogenative coupling (ADC) of alcohols and water/hydroxides is an emergent and graceful approach to produce carboxylic acids. Therefore, it is of high demand to develop active and practical catalysts/catalytic systems for this attractive transformation. Herein, we designed and fabricated a series of cyclometallated N-heterocyclic carbene-Ru (NHC-Ru) complexes via ligand tuning of [Ru-1], the superior complex in our previous work. Gratifyingly, gram-scale synthesis of carboxylic acids was efficiently enabled at an ultralow Ru loading (62.5 ppm) in open air. Moreover, effects of distinct ancillary NHC ligands and other parameters on this catalytic process were thoroughly studied, while further systematic studies were carried out to provide rationales for the activity trend of [Ru-1]-[Ru-7]. Finally, determination of quantitative green metrics illustrated that the present work exhibited superiority over representative literature reports. Hopefully, this study could provide valuable input for researchers who are engaging in metal-catalyzed ADC reactions.
Transformation of Thioacids into Carboxylic Acids via a Visible-Light-Promoted Atomic Substitution Process
Fu, Qiang,Liang, Fu-Shun,Lou, Da-Wei,Pan, Gao-Feng,Wang, Rui,Wu, Min,Xie, Kai-Jun
supporting information, p. 2020 - 2024 (2022/03/31)
A visible-light-promoted atomic substitution reaction for transforming thiocacids into carboxylic acids with dimethyl sulfoxide (DMSO) as the oxygen source has been developed, affording various alkyl and aryl carboxylic acids in over 90% yields. The atomic substitution process proceeds smoothly through the photochemical reactivity of the formed hydrogen-bonding adduct between thioacids and DMSO. A DMSO-involved proton-coupled electron transfer (PCET) and the simultaneous generation of thiyl and hydroxyl radicals are proposed to be key steps for realizing the transformation.
Fabrication, characterization and structure activity relationship of Co and Mn encapsulated on magnetic nanocomposite and its application in one-pot tandem synthesis of various tetrazoles and vitamin K3
Ashouri, Fatemeh,Farahanipour, Alireza,Faraji, Ali Reza,Hekmatian, Zahra
, (2022/02/21)
Considering the importance of vitamin K3 in commercial pet foods, veterinary medicines, poultry, and some swine feed and also tetrazole derivatives in pharmacy, medicine, chemistry, petroleum, and military industry, design efficient catalytic systems are desirable. Herein, four magnetic nanocomposites (MNCs) of cobalt and manganese using metformin, 3-aminopropyltrimethoxysilane (L1) and 2-aminoethyl-3-aminopropyltrimethoxysilane (L2) were designed and constructed as an efficient and controllable catalytic system. The synthesized nanocomposites fully characterized by FT-IR, AAS, ICP-OES, BET, CHN elemental analysis, SEM, TEM, DLS, EDX, TGA, VSM, and XPS spectroscopy. The well-prepared magnetically recoverable nanocomposites were used in the synthesis of a wide derivatives of α-hydrazino tetrazoles (α-HyT), ferrocenyltetrazoles (FcT), arylaminotetrazoles (ArAT) and also vitamin K3. Besides, the effect of operating parameters, such as the amount of catalyst, nature of solvent, temperature and reaction time, metal nature, chain length and hydrophobicity properties of linkers, was studied in the catalytic efficiency of synthesized nanocatalysts. The best catalytic results were obtained in the following order: FS-L2-Met@Co(II) > FS-L2-Met@Mn(II) > FS-L1-Met@Co(II) > FS-L1-Met@Mn(II) due to their structural characteristics. In addition to high TOF, these magnetic nanocomposites are superior in easy, inexpensive, and commercially preparation, keeping the structural and magnetic characteristics, easy magnetically separation from the reaction medium, short reaction time, mild reaction condition, easy work-up, and reusability without any metal leaching in six runs. Graphical abstract: [Figure not available: see fulltext.]
Comparative chemical and biological hydrolytic stability of homologous esters and isosteres
Barreiro, Eliezer J.,Fokoue, Harold H.,Freitas, Rosana H. C. N.,Gelves, Luis G. V.,Lima, Lidia M.,de Souza, Hygor M. R.,Guedes, Jéssica S.,Sant’Anna, Carlos Mauricio R.
, p. 718 - 727 (2022/03/14)
Esters are one of the major functional groups present in the structures of prodrugs and bioactive compounds. Their presence is often associated with hydrolytic lability. In this paper, we describe a comparative chemical and biological stability of homologous esters and isosteres in base media as well as in rat plasma and rat liver microsomes. Our results provided evidence for the hydrolytic structure lability relationship and demonstrated that the hydrolytic stability in plasma and liver microsome might depend on carboxylesterase activity. Molecular modelling studies were performed in order to understand the experimental data. Taken together, the data could be useful to design bioactive compounds or prodrugs based on the correct choice of the ester subunit, addressing compounds with higher or lower metabolic lability.
Aerobic oxidation of aldehydes to carboxylic acids catalyzed by recyclable ag/c3 n4 catalyst
Wu, Chaolong,Yao, Xiaoquan,Yu, Min,Zhou, Li,Zhu, Li
, p. 167 - 175 (2021/03/19)
The oxidation of aldehydes is an efficient methodology for the synthesis of carboxylic acids. Herein we hope to report a simple, efficient and recyclable protocol for aerobic oxidation of aldehydes to carboxylic acid by using C3N4 supported silver nanoparticles (Ag/C3N4) as a catalyst in aqueous solution under mild conditions. Under standard conditions, the corresponding carboxylic acids can be obtained in good to excellent yields. In addition, Ag/C3N4 is convenient for recovery and could be reused three times with satisfactory yields.
Fluorometric analysis of chlorite via oxidation of 9-anthracenecarboxaldehyde
Lee, Kang Min,Choi, Myung Gil,Yoo, Jae Hoon,Ahn, Sangdoo,Chang, Suk-Kyu
, (2021/05/03)
We investigated a simple fluorescence signaling method for the convenient analysis of a practical oxidant—chlorite—via the oxidation of 9-anthracenecarboxaldehyde to the corresponding carboxylic acid. 9-Anthracenecarboxaldehyde exhibited a marked ratiometric fluorescence signaling toward chlorite through manipulating its aggregation-induced emission property. The probe showed high chlorite-selectivity over other oxychlorine species as well as common metal ions, anions, and oxidants. Interference from a closely related oxidant, hypochlorite, was efficiently removed using DMSO as a scavenger. The proposed probe also exhibited a prominent ratiometric response through changes in UV–vis absorption behavior. Among the tested aromatic aldehydes (naphthaldehydes, anthracenecarboxaldehyde, and pyrenecarboxaldehyde), anthracene-based carboxaldehyde exhibited the most pronounced signaling contrast and the fastest signaling speed. The detection limit of chlorite determination was found to be 1.1 × 10–7 M. Exploitation of the probe for the convenient analysis of chlorite in tap water via a recovery test was conducted.
An Anionic, Chelating C(sp3)/NHC ligand from the Combination of an N-heterobicyclic Carbene and Barbituric Heterocycle
Benaissa, Idir,Gajda, Katarzyna,Vendier, Laure,Lugan, No?l,Kajetanowicz, Anna,Grela, Karol,Michelet, Véronique,César, Vincent,Bastin, Stéphanie
, p. 3223 - 3234 (2021/09/30)
The coordination chemistry of the anionic NHC1-based on an imidazo[1,5-a]pyridin-3-ylidene (IPy) platform substituted at the C5 position by an anionic barbituric heterocycle was studied with d6(Ru(II), Mn(I)) and d8(Pd(II), Rh(I), Ir(I), Au(III)) transition-metal centers. While the anionic barbituric heterocycle is planar in the zwitterionic NHC precursor 1·H, NMR spectroscopic analyses supplemented by X-ray diffraction studies evidenced the chelating behavior of ligand 1-through the carbenic and the malonic carbon atoms in all of the complexes, resulting from a deformation of the lateral barbituric heterocycle. The complexes were obtained by reaction of the free carbene with the appropriate metal precursor, except for the Au(III) complex 10, which was obtained by oxidation of the antecedent gold(I) complex [AuCl(1)]?with PhICl2as an external oxidant. During the course of the process, the kinetic gold(I) intermediate 9 resulting from the oxidation of the malonic carbon of the barbituric moiety was isolated upon crystallization from the reaction mixture. The νCOstretching frequencies recorded for complex [Rh(1)(CO)2] (5) demonstrated the strong donating character of the malonate-C(sp3)/NHC ligand 1-. The ruthenium complex [Ru(1)Cl(p-cymene)] (11) was implemented as a precatalyst in the dehydrogenative synthesis of carboxylic acid derivatives from primary alcohols and exhibited high activities at low catalyst loadings (25-250 ppm) and a large tolerance toward functional groups.
An efficient chromium(iii)-catalyzed aerobic oxidation of methylarenes in water for the green preparation of corresponding acids
Jiang, Feng,Liu, Shanshan,Wei, Yongge,Yan, Likai,Yu, Han,Zhao, Wenshu
supporting information, p. 12413 - 12418 (2021/09/28)
A highly efficient method to oxidize methylarenes to their corresponding acids with a reusable Cr catalyst was developed. The reaction can be carried out in water with 1 atm oxygen and K2S2O8as cooxidants, proceeds under green and mild conditions, and is suitable for the oxidation of both electron-deficient and electron-rich methylarenes, including heteroaryl methylarenes, even at the gram level. The excellent result, together with its simplicity of operation and the ability to continuously reuse the catalyst, makes this new methodology environmentally benign and cost-effective. The generality of this methodology gives it the potential for use on an industrial scale. Differing from the accepted oxidation mechanism of toluene, GC-MS studies and DFT calculations have revealed that the key benzyl alcohol intermediate is formed under the synergetic effect of the chromium and molybdenum in the Cr catalyst, which can be further oxidized to afford benzaldehyde and finally benzoic acid.
Cobalt-Catalyzed Deprotection of Allyl Carboxylic Esters Induced by Hydrogen Atom Transfer
Li, Nan,Gui, Yizhen,Chu, Mengqi,You, Mengdi,Qiu, Xiaohan,Liu, Hejia,Wang, Shiang,Deng, Meng,Ji, Baoming
supporting information, p. 8460 - 8464 (2021/11/13)
A brief, efficient method has been developed for the removal of the allyl protecting group from allyl carboxylic esters using a Co(II)/TBHP/(Me2SiH)2O catalytic system. This facile strategy displays excellent chemoselectivity, functional group tolerance, and high yields. This transformation probably occurs through the hydrogen atom transfer process, and a Co(III)-six-membered cyclic intermediate is recommended.
