4438-01-1Relevant academic research and scientific papers
Br?nsted acid catalysed chemo- andortho-selective aminomethylation of phenol
Li, Dongdong,Liu, Lu,Peng, Dan,Tang, Zhiqiong,Yue, Yidi
supporting information, p. 5777 - 5781 (2021/07/12)
We have developed a Br?nsted acid catalysed highlyortho-selective functionalization of free phenols with readily availableN,O-acetals under mild conditions, furnishing various corresponding aminomethylated phenol products in moderate to excellent yields. The salient features of this transformation include mild conditions, good substrate scope, excellentortho-selectivity, high efficiency, and ease of further transformation.
Decarbonylative Synthesis of Aryl Nitriles from Aromatic Esters and Organocyanides by a Nickel Catalyst
Iizumi, Keiichiro,Kurosawa, Miki B.,Isshiki, Ryota,Muto, Kei,Yamaguchi, Junichiro
supporting information, p. 1555 - 1559 (2020/11/10)
A decarbonylative cyanation of aromatic esters with aminoacetonitriles in the presence of a nickel catalyst was developed. The key to this reaction was the use of a thiophene-based diphosphine ligand, dcypt, permitting the synthesis of aryl nitrile without the generation of stoichiometric metal- or halogen-containing chemical wastes. A wide range of aromatic esters, including hetarenes and pharmaceutical molecules, can be converted into aryl nitriles.
Acetyl Acetone Covalent Triazine Framework: An Efficient Carbon Capture and Storage Material and a Highly Stable Heterogeneous Catalyst
Jena, Himanshu Sekhar,Krishnaraj, Chidharth,Wang, Guangbo,Leus, Karen,Schmidt, Johannes,Chaoui, Nicolas,Van Der Voort, Pascal
, (2018/06/11)
We present, for the first time, Covalent Triazine Frameworks functionalized with acetyl acetonate group (acac-CTFs). They are obtained from the polymerization of 4,4'-malonyldibenzonitrile under ionothermal conditions and exhibit BET surface areas up to 1626 m2/g. The materials show excellent CO2 uptake (3.30 mmol/g at 273 K and 1 bar), H2 storage capacity (1.53 wt% at 77 K and 1 bar) and a good CO2/N2 selectivity (up to 46 at 298 K). The enhanced CO2 uptake value and good selectivity are due to the presence of dual polar sites (N and O) throughout the material. In addition, acac-CTF was used to anchor VO(acac)2 as a heterogeneous catalyst. The V@acacCTF showed outstanding reactivity and reusability for the modified Mannich-type reaction with a higher turnover number than the homogeneous catalyst. The higher reactivity and reusability of the catalyst comes from the coordination of the vanadyl ions to the acetyl acetonate groups present in the material. The strong metalation is confirmed from Fourier Transform Infrared analysis, 13C MAS NMR spectral analysis and X-ray photoelectron spectroscopy measurement. Detailed characterization of the V@acac-CTF reveals that electron donation from O^O of the acetyl acetonate group to VO(acac)2, combined with the very high surface area of acac-CTF, is responsible for the stabilization of the catalyst. Overall, this contribution highlights the necessity of stable catalytic binding sites on heterogeneous supports to fabricate greener catalysts for sustainable chemistry.
The modified-Mannich reaction: Conversion of arylboronic acids and subsequent coupling with paraformaldehyde and amines toward the one-pot synthesis of Mannich bases and benzoxazines
Liu, Juan,Yuan, Gaoqing
supporting information, p. 1470 - 1473 (2017/03/23)
A modified Mannich reaction has been developed for the synthesis of Mannich bases and benzoxazines via the oxidative hydroxylation of arylboronic acids and subsequent coupling with paraformaldehyde and amines in one pot. This modified Mannich reaction is easily carried out to afford the target products in good to excellent yields and tolerates a variety of functional groups.
Cu(II)-Catalyzed ortho-Selective Aminomethylation of Phenols
Dai, Jin-Ling,Shao, Nan-Qi,Zhang, Jin,Jia, Run-Ping,Wang, Dong-Hui
supporting information, p. 12390 - 12393 (2017/09/23)
A Cu(II)-catalyzed ortho-selective functionalization of free phenols with trifluoroborates to afford Csp2-Csp3 coupling products under mild conditions has been developed. A variety of functional groups on the phenol and the potassium aminomethyltrifluoroborate substrates were found compatible, furnishing the corresponding products in moderate to excellent yields. A single-electron transfer radical coupling mechanism involving a six-membered transition state is proposed to rationalize the high levels of ortho-selectivity in the reaction. This protocol provides straightforward access to ortho-aminomethyl-substituted phenols, unnatural amino acids and other bioactive small molecules.
Redox-neutral α-oxygenation of amines: Reaction development and elucidation of the mechanism
Richers, Matthew T.,Breugst, Martin,Platonova, Alena Yu.,Ullrich, Anja,Dieckmann, Arne,Houk,Seidel, Daniel
, p. 6123 - 6135 (2014/05/20)
Cyclic secondary amines and 2-hydroxybenzaldehydes or related ketones react to furnish benzo[e][1,3]oxazine structures in generally good yields. This overall redox-neutral amine α-C-H functionalization features a combined reductive N-alkylation/oxidative α-functionalization and is catalyzed by acetic acid. In contrast to previous reports, no external oxidants or metal catalysts are required. Reactions performed under modified conditions lead to an apparent reductive amination and the formation of o-hydroxybenzylamines in a process that involves the oxidation of a second equivalent of amine. A detailed computational study employing density functional theory compares different mechanistic pathways and is used to explain the observed experimental findings. Furthermore, these results also reveal the origin of the catalytic efficiency of acetic acid in these transformations.
Anionic ortho-fries rearrangement, a facile route to arenol-based mannich bases
Assimomytis, Nikos,Sariyannis, Yiannis,Stavropoulos, Georgios,Tsoungas, Petros G.,Varvounis, George,Cordopatis, Paul
experimental part, p. 2777 - 2782 (2010/03/03)
Phenol and 1-naphthol-based carbamates undergo the anionic ortho-Fries rearrangement to their corresponding amides. Bulky substitution at position 8 of 1-naphthol-based carbamates makes the rearrangement an exclusive reaction, even at -90 C, under a variety of conditions. The amides can be efficiently reduced to the corresponding Mannich bases. A novel route to 7-[(dialkylamino)methyl]-8- hydroxy-1-naphthaldehydes is presented.
Regioselective mannich reaction of phenols under high pressure using dichloromethane as C1 unit
Matsumoto, Kiyoshi,Joho, Kouta,Mimori, Seisuke,Iida, Hirokazu,Hamana, Hiroshi,Kakehi, Akikazu
scheme or table, p. 1061 - 1067 (2009/06/28)
Regioselectivity in Mannich reaction of 4-, 3-, and 2-substituted phenols with typical heterocyclic amines are investigated under reaction conditions developed by us. Phenol and 4-alkyl, and 4-chlorophenols in the title reaction predominantly gave the corresponding 2-(aminomethyl)phenols, while 4-methoxyphenol afforded, in addition to the mono(aminomethyl)phenols, a considerable amount of the bis adducts. Peculiarly enough, 3-methylphenol with amines afforded 3-methyl-4-(aminomethyl)phenols whereas 2-methylphenol produced 2-methyl-6-(aminomethyl)phenols.
Substituents on quinone methides strongly modulate formation and stability of their nucleophilic adducts
Weinert, Emily E.,Dondi, Ruggero,Colloredo-Melz, Stefano,Frankenfield, Kristen N.,Mitchell, Charles H.,Freccero, Mauro,Rokita, Steven E.
, p. 11940 - 11947 (2007/10/03)
Electronic perturbation of quinone methides (QM) greatly influences their stability and in turn alters the kinetics and product profile of QM reaction with deoxynucleosides. Consistent with the electron-deficient nature of this reactive intermediate, electron-donating substituents are stabilizing and electron-withdrawing substituents are destabilizing. For example, a dC N3-QM adduct is made stable over the course of observation (7 days) by the presence of an electron-withdrawing ester group that inhibits QM regeneration. Conversely, a related adduct with an electron-donating methyl group is very labile and regenerates its QM with a half-life of approximately 5 h. The generality of these effects is demonstrated with a series of alternative quinone methide precursors (QMP) containing a variety of substituents attached at different positions with respect to the exocyclic methylene. The rates of nucleophilic addition to substituted QMs measured by laser flash photolysis similarly span 5 orders of magnitude with electron-rich species reacting most slowly and electron-deficient species reacting most quickly. The reversibility of QM reaction can now be predictably adjusted for any desired application.
