30780-19-9Relevant academic research and scientific papers
Cucurbiturils Monofunctionalized on the Methylene Bridge and Their Host-Guest Properties
Kandrnálová, Markéta,?indelá?, Vladimír
, p. 4733 - 4736 (2021)
Monofunctionalization of cucurbiturils is essential for transferring these potent supramolecular macrocyclic hosts into real-world application. Here, we present the synthesis of cucurbit[6]urils 1 and 2 in which one methylene bridge is modified by a single substituent containing a nitro or an ammonium group. We investigated host–guest properties in water and 0.2 M NaCl using 1H?NMR and isothermal titration calorimetry, particularly for 2. The macrocycle 2 self-associated into dimeric aggregates in pure water, but readily disassembled in the presence of NaCl or organic cations. Cucurbit[7]uril was able to encapsulate the ammonium substituent of 2 inside its cavity resulting in a complex of 1 : 1 stoichiometry with an association constant of 3.1×105 M?1. The presented host–guest properties together with further possible derivatization showcase the potential of cucurbiturils modified in the methylene position such as 1 and 2 for the development of advanced supramolecular systems.
Pd-Catalyzed Regio- and Stereoselective sp3 C?H Arylation of Primary Aliphatic Amines: Mechanistic Studies and Synthetic Applications
Ha, Hyeonbin,Choi, Ho Jeong,Park, Hahyoun,Gwon, Yunyeong,Lee, Jiin,Kwak, Jaesung,Kim, Min,Jung, Byunghyuck
supporting information, p. 1136 - 1145 (2021/02/12)
The Pd-catalyzed γ-position sp3?C?H arylation of primary amines bearing an aliphatic chain or cycloalkyl substituent and related mechanistic studies are disclosed. 3-Bromo-2-hydroxybenzaldehyde plays a key role in γ-position sp3?C?H arylation as a transient directing group (TDG) to assist the regio- and stereoselective C?H activation of a Pd catalyst, and the development of a tandem reaction to transform 1°-amines into γ-aryl-substituted ketones demonstrates synthetic utility. Density functional theory (DFT)-based calculations revealed the detailed reaction mechanism and the origins of the high selectivity (γ-position and cis-only). The X-ray crystal structure of the isolated endo-palladacycle intermediate supported the DFT results, and a kinetic isotope experiment confirmed the results of DFT calculations indicating that the C?H activation step via simultaneous palladation and deprotonation is rate-determining.
Iron powder and tin/tin chloride as new reducing agents of Meerwein arylation reaction with unexpected recycling to anilines
Abdelwahab, Ahmed B.,El-Sawy, Eslam R.,Kirsch, Gilbert
supporting information, p. 526 - 538 (2020/01/08)
Simple and rapid route for Meerwein arylation reaction using iron powder or a mixture of tin/tin chloride has been developed. In the presence of iron powder, different aryl diazonium salts reacted with methyl vinyl ketone, acrylates, and isopropenyl acetate. Production of oximes was detected as the main product with acrylates or in a mixture with β-aryl methyl ketones in the case of methyl vinyl ketone. The in situ produced HNO2 from an excess of NaNO2/HCl was trapped by alkyl aryl radical to form oximes in the E configuration form. The presence of tin/tin chloride mixture in the reaction of the aryl diazonium salts with methyl vinyl ketone produced Michael products along with β-aryl methyl ketones. The predicted α-aryl methyl ketones from the reaction of isopropenyl acetate with the diazotized anilines were obtained using iron or tin/tin chloride mixture.
Synthetic preparation method of stable isotope labeled phenylethanolamine A
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Paragraph 0037; 0039; 0040; 0044; 0045; 0049; 0050, (2021/03/05)
The invention discloses a synthetic preparation method of stable isotope labeled phenylethanolamine A. The synthetic preparation method comprises the following steps of: S1) firstly reacting p-nitrobenzaldehyde with acetyltriphenylphosphine, and then conducting reducing by trichlorosilane to obtain a compound shown as formula 1; S2) carrying out reductive amination reaction on the compound shown as formula 1 to obtain a compound shown as formula 2; S3) subjecting bromo-p-hydroxyacetophenone and deuterated methanol to Mmitsunobu reaction so as to obtain deuterium-labeled bromo-p-methoxyacetophenone shown as formula 3; and S4) carrying out nucleophilic reaction on the compounds shown as formula 2 and formula 3 in methanol, and directly performing reduction by using a hydroboration reagent toobtain the target compound stable isotope labeled phenylethanolamine A. According to the method, cheap p-nitrobenzaldehyde and p-hydroxyacetophenone are used as the raw materials, phenylethanolamineA with purity and abundance both up to 98% or above can be prepared through simple synthesis of four steps, the experiment steps are few, the operation is simple, and the detection cost is greatly reduced.
Synthetic method of phenylethanolamine A
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, (2019/05/28)
The invention discloses a method for preparing phenylethanolamine A. The method includes the following steps: 1) reacting p-methoxyacetophenone in an HBr/DMSO system to obtain acetophenone aldehyde monohydrate and acetophenone aldehyde; 2) subjecting the acetophenone aldehyde and 4(4-nitrophenyl)butane-2-amine to bimolecular substitution reaction, and subjecting an intermediate product obtained bythe reaction to reduction reaction by potassium borohydride to obtain the phenylethanolamine A. The method has the advantages that the reactions are simple, the reaction steps are reduced, and the high-yield phenylethanolamine A is obtained.
Mild Chemoenzymatic Oxidation of Allylic sec-Alcohols. Application to Biocatalytic Stereoselective Redox Isomerizations
Martínez-Montero, Lía,Gotor, Vicente,Gotor-Fernández, Vicente,Lavandera, Iván
, p. 2413 - 2419 (2018/03/13)
The design of catalytic oxidative methodologies in aqueous medium under mild reaction conditions and using molecular oxygen as final electron acceptor represents a suitable alternative to the traditional oxidative transformations. These methods are especially relevant if other functionalities that can be oxidized are present within the same molecule, as in the case of allylic alcohols. Herein we apply a simple chemoenzymatic system composed of the laccase from Trametes versicolor and 2,2,6,6-tetramethylpiperidinyloxy radical (TEMPO) to oxidize a series of racemic allylic sec-alcohols into the corresponding α,β-unsaturated ketones. Afterward, these compounds react with different commercially available ene-reductases to afford the corresponding saturated ketones. Remarkably, in the case of trisubstituted alkenes, the bioreduction reaction occurred with high stereoselectivity. Overall, a bienzymatic one-pot two-step sequential strategy has been described with respect to the synthesis of saturated ketones starting from racemic allylic alcohols, thus resembling the metal-catalyzed redox isomerizations of these derivatives that have been previously reported in the literature.
Preparation method of phenylethanolamine A
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, (2018/03/24)
The invention discloses a preparation method of phenylethanolamine A. The preparation method comprises the following steps that firstly, a nucleophilic substitution reaction is conducted on nitrobenzyl bromide and ethyl acetoacetate to obtain a compound shown in a formula 1; secondly, under an acidic condition, the compound shown in the formula 1 is subjected to an acidic hydrolysis reaction to obtain a compound shown in a formula 2; thirdly, the compound shown in the formula 2 and formamide are subjected to a Leuckart reaction to obtain a compound shown in a formula 3; fourthly, a nucleophilic substitution reaction is conducted on the compound shown in the formula 3 and bromo-p-methoxyacetophenone; potassium borohydride or sodium borohydride is added into a nucleophilic substitution reaction system, and a reduction reaction is conducted to obtain the phenylethanolamine A. The preparation method is short in reaction route, the synthesis efficiency is high, the separation and purification steps are reduced, and mass production can be achieved.
Method for preparing phenylethanolamine compound intermediate
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Paragraph 0105; 0108, (2018/05/07)
The invention discloses a method for preparing a phenylethanolamine compound intermediate. The method comprises the following steps: (1) carrying out a nitrifying reaction on 1-methyl-3-phenylpropylamine and a nitrifying reagent to obtain a 4-(4-nitrophenyl)-butan-2-amine and 4-(2-nitrophenyl)-butan-2-amine mixture; and (2) reacting the mixture obtained in step (1) with a compound of formula III,and separating the obtained reaction product to obtain the phenylethanolamine compound intermediate of formula I. The method for preparing the phenylethanolamine compound intermediate has the advantages of simplicity in operation, short route and few steps; and an o-nitro impurities generated in the nitrifying reaction can be easily removed after being reacted without separation and becoming corresponding amides, so the reaction yield and the product purity are high, and the industrial production of the product is facilitated.
Novel 4-(4-substituted amidobenzyl)furan-2(5H)-one derivatives as topoisomerase I inhibitors
Peng, Cheng-Kang,Zeng, Ting,Xu, Xing-Jun,Chang, Yi-Qun,Hou, Wen,Lu, Kuo,Lin, Hui,Sun, Ping-Hua,Lin, Jing,Chen, Wei-Min
, p. 187 - 199 (2017/01/06)
In this study, two series of novel 4-(4-substituted amidobenzyl)furan-2(5H)-one derivatives containing an α,β-unsaturated lactone fragment were synthesized and screened for Topo I inhibition and antitumor activity. The topoisomerase I inhibitory activities and cytotoxicities against three human cancer cell lines (MCF-7,Hela,A549) were evaluated. The results revealed that series 2, compounds bearing an exocyclic double bond on the furanone ring, generally showed more potent activity than series 1, compounds lacking an exocyclic double bond. Several compounds of series 2 possess significant Topo I inhibitory activity and potent antiproliferative activity against cancer cell lines. Further mechanism studies of the most active compound of series 2 (B-15) indicated that synthetic compounds can not only stabilize the drug-enzyme-DNA covalent ternary complex as well as camptothecin, but also interfere with the binding between Topo I and DNA. The binding patterns of these compounds with Topo I and structure-activity relationships are discussed.
A Hantzsch Amido Dihydropyridine as a Transfer Hydrogenation Reagent for α,β-Unsaturated Ketones
Van Arman, Scott A.,Zimmet, Austin J.,Murray, Ian E.
, p. 3528 - 3532 (2016/05/24)
An improved synthesis of the bis-methylamido Hantzsch dihydropyridine is described. The Hantzsch amide is demonstrated to be an effective transfer hydrogenation reagent using α,β-unsaturated ketones as the test case. Unreacted Hantzsch amide and the bis-methylamidopyridine byproduct are effectively removed by extraction in contrast to the commonly used Hantzsch diethyl ester. Several examples are given with the reaction being more effective for conjugated aromatic substrates than for aliphatics.
