2005-08-5Relevant articles and documents
Structural studies of a novel bioactive benzophenone derivative: (4-Chloro-2-hydroxy-phenyl)-phenyl-methanone
Zabiulla,Naveen,Begum, A. Bushra,Khanum, Shaukath Ara,Lokanath
, p. 233 - 237 (2016)
The title compound (4-Chloro-2-hydroxy-phenyl)-phenyl-methanone was synthesized and the product obtained was characterized by spectroscopic techniques, and finally the structure was confirmed by X-ray diffraction studies. The compound crystallizes in the orthorhombic crystal system with the space group Pbca with unit cell parameters, a = 14.0359(5) ?, b = 6.8084(3) ?, c = 23.1097(8) ?, and Z = 4. The structure exhibits an intramolecular hydrogen bond which closes an S(6) ring. No directional interactions beyond the van der Waals packing contacts were identified in the crystal structure.
Hydrogen-bond-assisted transition-metal-free catalytic transformation of amides to esters
Huang, Changyu,Li, Jinpeng,Wang, Jiaquan,Zheng, Qingshu,Li, Zhenhua,Tu, Tao
, p. 66 - 71 (2020/11/18)
The amide C-N cleavage has drawn a broad interest in synthetic chemistry, biological process and pharmaceutical industry. Transition-metal, luxury ligand or excess base were always vital to the transformation. Here, we developed a transition-metal-free hydrogen-bond-assisted esterification of amides with only catalytic amount of base. The proposed crucial role of hydrogen bonding for assisting esterification was supported by control experiments, density functional theory (DFT) calculations and kinetic studies. Besides broad substrate scopes and excellent functional groups tolerance, this base-catalyzed protocol complements the conventional transition-metal-catalyzed esterification of amides and provides a new pathway to catalytic cleavage of amide C-N bonds for organic synthesis and pharmaceutical industry. [Figure not available: see fulltext.]
Mechanically induced solvent-free esterification method at room temperature
Zheng, Lei,Sun, Chen,Xu, Wenhao,Dushkin, Alexandr V.,Polyakov, Nikolay,Su, Weike,Yu, Jingbo
, p. 5080 - 5085 (2021/02/05)
Herein, we describe two novel strategies for the synthesis of esters, as achieved under high-speed ball-milling (HSBM) conditions at room temperature. In the presence of I2 and KH2PO2, the reactions afford the desired esterification derivatives in 45% to 91% yields within 20 min of grinding. Meanwhile, using KI and P(OEt)3, esterification products can be obtained in 24% to 85% yields after 60 min of grinding. In addition, the I2/KH2PO2 protocol was successfully extended to the late-stage diversification of natural products showing the robustness of this useful approach. Further application of this method in the synthesis of inositol nicotinate was also discussed. This journal is
Substituent and Surfactant Effects on the Photochemical Reaction of Some Aryl Benzoates in Micellar Green Environment?
Siano, Gastón,Crespi, Stefano,Bonesi, Sergio M.
, p. 1298 - 1309 (2021/05/07)
In this study, we carried out preparative and mechanistic studies on the photochemical reaction of a series of p-substituted phenyl benzoates in confined and sustainable micellar environment. The aim of this work is mainly focused to show whether the nature of the surfactant (ionic or nonionic) leads to noticeable selectivity in the photoproduct formation and whether the electronic effects of the substituents affect the chemical yields and the rate of formation of the 5-substituted-2-hydroxybenzophenone derivatives. Application of the Hammett linear free energy relationship (LFER) on the rate of formation of benzophenone derivatives, on the lower energy band of the UV-visible absorption spectra of the aryl benzoates and 5-substituted-2-hydroxybenzophenone derivatives allows a satisfactory quantification of the substituent effects. Furthermore, UV-visible and 2D-NMR (NOESY) spectroscopies have been employed to measure the binding constant Kb and the location of the aryl benzoates within the hydrophobic core of the micelle. Finally, TD-DFT calculations have been carried out to estimate the energies of the absorption bands of p-substituted phenyl benzoates and 5-substituted-2-hydroxybenzophenone derivatives providing good linear correlation with those values measured experimentally.
Dual aminoquinolate diarylboron and nickel catalysed metallaphotoredox platform for carbon-oxygen bond construction
Day, Craig,Jia, Xin,Wei, Lanfeng,Xu, Liang,Zu, Weisai
supporting information, p. 8273 - 8276 (2020/08/17)
Herein, aminoquinolate diarylboron complexes are utilized as photocatalysts in dual Ni/photoredox catalyzed carbon-oxygen construction reactions. Via this unified metallaphotoredox platform, diverse (hetero)aryl halides can be conveniently coupled with acids, alcohols and water. This method features operational simplicity, broad substrate scope and good compatibility with functional groups. This journal is
Synthesis of cycloalkyl/steroidal heteroaryl sulfides using rhodium-catalyzed heteroaryl exchange reaction
Arisawa, Mieko,Nakai, Katsuya,Suzuki, Ren,Yamada, Tomoki,Yamaguchi, Masahiko
, p. 104 - 118 (2020/01/28)
Cycloalkyl heteroaryl sulfides are efficiently synthesized by the single-bond cleavage and exchange reaction of S-cycloalkyl thioesters and heteroaryl ethers without using a base. The method is applicable to steroids at the A- and D-rings, and provides diverse heteroarylthiolated steroids with five- and six-membered heteroarenes.
Nickel-Catalyzed Cross-Coupling of Aryl Redoxactive Esters with Aryl Zinc Reagents
Shih, Bo-Hao,Basha, R. Sidick,Lee, Chin Fa
, p. 8862 - 8866 (2019/09/30)
A nickel-catalyzed aryl-aroyloxyl C(sp2)-O radical cross-coupling reaction conducted using a redox active ester with aryl zinc reagent was developed. This method demonstrates a new disconnection approach for formation of aryl aryl esters. In the one-pot sequential process, the readily available aryl carboxylic acids can be converted into functionalized aryl aryl esters and heteroaryl esters. This protocol is amenable to the gram-scale synthesis. The present method has a wide substrate scope and high functional group tolerance.
Base-Promoted Amidation and Esterification of Imidazolium Salts via Acyl C-C bond Cleavage: Access to Aromatic Amides and Esters
Karthik, Shanmugam,Muthuvel, Karthick,Gandhi, Thirumanavelan
, p. 738 - 751 (2019/01/24)
Imidazolium salts have been effectively employed as suitable acyl transfer agents in amidation and esterification in organic synthesis. The weak acyl C(O)-C imidazolium bond was exploited to generate acyl electrophiles, which further react with amines and alcohols to afford amides and esters. The broad substrate scope of anilines and benzylic amines and base-promoted conditions are the benefits of this route. Interestingly, phenol, benzylic alcohols, and a biologically active alcohol can also be subjected to esterification under the optimized conditions.
Oxime palladacycle in PEG as a highly efficient and recyclable catalytic system for phenoxycarbonylation of aryl iodides with phenols
Gaikwad, Vinayak V.,Bhanage, Bhalchandra M.
, (2019/02/19)
In this report, we have developed a sustainable protocol for the synthesis of aromatic esters by a carbonylative method using di-μ-chlorobis [5-hydroxy-2-[1-(hydroxyimino-?N) ethyl] phenyl-?C] palladium (II) dimer (1) catalyst in PEG-400 as a greener and recyclable solvent. The reaction is carried out at room temperature using CO in a balloon. Good to excellent yield of various esters can be synthesize using this protocol. Direct insertion of CO moiety leads to the high atom and step economy. Compared to previous protocol this phosphine free approach for the synthesis of aromatic esters provides high Turnover Number (TON) and Turnover Frequency (TOF). Developed approach has an alternative route for use of conventional palladium precursor with high conversion and selectivity. The catalyst system and product can easily be separated using diethyl ether as a solvent. The Pd/PEG-400 system could be reused up to a fifth consecutive cycle without any loss of its activity and selectivity.
Transesterification of (hetero)aryl esters with phenols by an Earth-abundant metal catalyst
Chen, Jianxia,Namila,Bai, Chaolumen,Baiyin, Menghe,Agula, Bao,Bao, Yong-Sheng
, p. 25168 - 25176 (2018/07/29)
Readily available and inexpensive Earth-abundant alkali metal species are used as efficient catalysts for the transesterification of aryl or heteroaryl esters with phenols which is a challenging and underdeveloped transformation. The simple conditions and the use of heterogeneous alkali metal catalyst make this protocol very environmentally friendly and practical. This reaction fills in the missing part in transesterification reaction of phenols and provides an efficient approach to aryl esters, which are widely used in the synthetic and pharmaceutical industry.
