19072-58-3Relevant articles and documents
Iron-catalyzed arene C-H hydroxylation
Cheng, Lu,Wang, Huihui,Cai, Hengrui,Zhang, Jie,Gong, Xu,Han, Wei
, p. 77 - 81 (2021/10/05)
The sustainable, undirected, and selective catalytic hydroxylation of arenes remains an ongoing research challenge because of the relative inertness of aryl carbon-hydrogen bonds, the higher reactivity of the phenolic products leading to over-oxidized by-products, and the frequently insufficient regioselectivity. We report that iron coordinated by a bioinspired L-cystine-derived ligand can catalyze undirected arene carbon-hydrogen hydroxylation with hydrogen peroxide as the terminal oxidant. The reaction is distinguished by its broad substrate scope, excellent selectivity, and good yields, and it showcases compatibility with oxidation-sensitive functional groups, such as alcohols, polyphenols, aldehydes, and even a boronic acid. This method is well suited for the synthesis of polyphenols through multiple carbon-hydrogen hydroxylations, as well as the late-stage functionalization of natural products and drug molecules.
SUBSTITUTED CONDENSED THIOPHENES AS MODULATORS OF STING
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Page/Page column 104-105, (2019/12/04)
A compound of formula (I), wherein: R1 is selected from (i) H, (ii) C3-6cycloalkyl, (iii) C3-7heterocyclyl optionally substituted with a group selected from: methyl and ester, and (iv) linear or branched C1-4alkyl optionally substituted with a group selected from: alkoxy, amino, amido, acylamido, acyloxy, alkyl carboxyl ester, alkyl carbamoyl, alkyl carbamoyl ester, phenyl, phosphonate ester, C3-7heterocyclyl optionally substituted with a group selected from methyl and oxo, and a naturally occurring amino acid, optionally N-substituted with a group selected from methyl, acetyl and boc; A1 is CRA or N; A2 is CRB or N; A3 is CRC or N; A4 is CRD or N; where no more than two of A1, A2, A3, and A4 may be N; one or two of RA, RB, RC, and RD, (if present) are selected from H, F, Cl, Br, Me, CF3, cyclopropyl, cyano, OMe, OEt, CH2OH, CH2OMe and CH2NMe2; the remainder of RA, RB, RC, and RD, (if present) are H; Y is O, NH or CH2; RY is selected from: (RYA) and (RYB).
Highly efficient synthesis of primary amides: Via aldoximes rearrangement in water under air atmosphere catalyzed by an ionic ruthenium pincer complex
Yang, Fa-Liu,Zhu, Xinju,Rao, Dun-Kang,Cao, Xiao-Niu,Li, Ke,Xu, Yan,Hao, Xin-Qi,Song, Mao-Ping
, p. 37093 - 37098 (2016/05/24)
The transformation of aldoximes to primary amides has been evaluated using pincer ruthenium complexes a-c, among which the ionic Ru catalyst a proved to be the most efficient in water under air atmosphere. A variety of (hetero)arene aldoximes proceeded smoothly to afford amides in high yields with good functional group compatibilities. Furthermore, a direct synthetic route of amides from aldehydes, hydroxylamine hydrochloride and sodium carbonate was also described with broad substrates including conjugated and aliphatic aldehydes. This protocol is operationally simple and proceeds with a low catalyst loading (0.5 mol%).
Aminofluorene-Mediated Biomimetic Domino Amination-Oxygenation of Aldehydes to Amides
Ghosh, Santanu,Jana, Chandan K.
supporting information, p. 5788 - 5791 (2016/11/29)
A conceptually novel biomimetic strategy based on a domino amination-oxygenation reaction was developed for direct amidation of aldehydes under metal-free conditions employing molecular oxygen as the oxidant. 9-Aminofluorene derivatives acted as pyridoxamine-5′-phosphate equivalents for efficient, chemoselective, and operationally simple amine-transfer oxygenation reaction. Unprecedented RNH transfer involving secondary amine to produce secondary amides was achieved. In the presence of 18O2, 18O-amide was formed with excellent (95%) isotopic purity.
Stannous chloride dihydrate-mediated efficient access to secondary and primary amides from oximes
Ganguly, Nemai C.,Nayek, Subhasis,Chandra, Sumanta
, p. 1695 - 1702 (2014/01/17)
Highly selective, efficient and expeditious Beckmann rearrangement of a wide range of ketoximes to secondary amides (20 examples) has been accomplished using stoichiometric amount of stannous chloride dihydrate in the presence of nucleophilic additive, tetra-n-butylammonium iodide (TBAI) (10 moI%) and 4 ? MS in dry acetonitrile at reflux temperature. Aldoximes delivered primary amides through intermediacy of nitriles upon heating with an equimolar amount of SnCl2·2H2O and DBU in dry toluene at reflux in good to acceptable yields (12 examples). Utilization of mild Lewis acid, inexpensive rack reagents and procedural simplicity including easy isolation of products are key advantageous features of the protocol.
An efficient copper(II)-catalyzed direct access to primary amides from aldehydes under neat conditions
Ganguly, Nemai C.,Roy, Sushmita,Mondal, Pallab
experimental part, p. 1413 - 1416 (2012/03/27)
A simple expeditious one-pot conversion of a wide assortment of aldehydes to corresponding primary amides in good to excellent yields has been accomplished employing hydroxylamine hydrochloride (1 mol equiv), sodium acetate (1.1 mol equiv), and copper sulfate pentahydrate (5 mol %) under neat conditions at 110 °C. The protocol based upon ligand-free copper (II)-catalysis avoids the use of relatively expensive late transition metal-based catalysts, and is performed under operationally simple conditions without any demanding procedure of isolation and purification of products.
Studies of nitrile oxide cycloadditions, and the phenolic oxidative coupling of vanillin aldoxime by Geobacillus sp. DDS012 from Italian rye grass silage
Kelly, David R.,Baker, Simon C.,King, David S.,De Silva, Deepa S.,Lord, Gwyn,Taylor, Jason P.
, p. XX787-796 (2008/09/17)
During studies directed towards the discovery of nitrile hydrolysing enzymes from thermophiles, vanillin aldoxime was incubated with the thermophilic organism, Geobacillus sp. DDS012 isolated from Italian rye grass (Lolium multiflorum) silage. The predominant product was a dihydro-dimer, which could only be characterised by LC-MS. This was initially imagined to be the product of cycloaddition of vanillin aldoxime with the corresponding nitrile oxide, but preparation of the supposed adduct and model studies excluded this possibility. The rate constant for the second order dimerisation of 4-O-acetyl vanillin nitrile oxide was measured (1.21 × 10-4 M-1 s -1, 0.413 M, 25 °C) and the 13C-NMR signal for the nitrile oxide carbon was observed (δC 34.4, br. t 1J13C,14N circa 50 Hz). Treatment of vanillin aldoxime with potassium persulfate and iron sulfate gave material with the same LC-MS properties as the natural product, which is therefore identified as 5,5′-dehydro-di-(vanillin aldoxime) 1d formed by phenolic oxidative coupling. This journal is The Royal Society of Chemistry.
Enzymatic nitrile hydrolysis catalyzed by nitrilase ZmNIT2 from maize. An unprecedented β-hydroxy functionality enhanced amide formation
Mukherjee, Chandrani,Zhu, Dunming,Biehl, Edward R.,Parmar, Rajiv R.,Hua, Ling
, p. 6150 - 6154 (2007/10/03)
To explore the synthetic potential of nitrilase ZmNIT2 from maize, the substrate specificity of this nitrilase was studied with a diverse collection of nitriles. The nitrilase ZmNIT2 showed high activity for all the tested nitriles except benzonitrile, producing both acids and amides. For the hydrolysis of aliphatic, aromatic nitriles, phenylacetonitrile derivatives and dinitriles, carboxylic acids were the major products. Unexpectedly, amides were found to be the major products in nitrilase ZmNIT2-catalyzed hydrolysis of β-hydroxy nitriles. The hydrogen bonding between the hydroxyl group and nitrogen in the enzyme-substrate complex intermediates that disfavors the loss of ammonia and formation of acyl-enzyme intermediate, which was further hydrolyzed to acid, was proposed to be responsible for the unprecedented β-hydroxy functionality assisted high yield of amide formation.
