596-29-2Relevant articles and documents
FORMATION OF CARBENIUM IONS AND NAKED ANIONS BY THE PROTONATION OF PHTHALOPHENONE WITH A SUPER ACID.
Brandner,Dickert,Lehmann
, p. 740 - 745 (1987)
Two molecules of a strong acid such as CF//3SO//3H are necessary to cleave the lactone ring of phthalophenone. NMR and conductivity measurements reveal that the carboxylate group has to be protonated for this purpose followed by its solvation with an additional molecule of acid. But CF//3SO//3** minus which is simultaneously formed behaves as a naked anion in the solvent dichloromethane. CNDO-calculations indicate a strong interaction between the charged central carbon atom and the COOH group in o-HOOH(C//6H//4)C** plus (C//6H//5)//2 which is accompanied by an unusually large twisting of the phenyl rings.
Phthalide synthesis through dehydrogenated lactonization of the C(sp3)-H bond by photoredox catalysis
Cai, Shunyou,Cai, Zhixiong,Chen, Shanyi,Huang, Mingqiang,Lai, Qihong,Lin, Yulin,Liu, Chao,Liu, Hui
, p. 8212 - 8216 (2021/10/29)
A practical and efficient method is established for the direct oxidative lactonization of the C(sp3)-H bonds relying on visible-light-induced photoredox catalysis. This protocol expediently allows the delivery of diverse phthalides using oxygen as the sole terminal oxidant under metal-free conditions at room temperature. Notably, the choice of an appropriate hydrogen atom transfer (HAT) cocatalyst is revealed to be critical for the success of this process.
Base-Directed Photoredox Activation of C-H Bonds by PCET
Ener, Maraia E.,Darcy, Julia W.,Menges, Fabian S.,Mayer, James M.
supporting information, p. 7175 - 7180 (2020/07/14)
Photoredox catalysis using proton-coupled electron transfer (PCET) has emerged as a powerful method for bond transformations. We previously employed traditional chemical oxidants to achieve multiple-site concerted proton-electron transfer (MS-CPET) activation of a C-H bond in a proof-of-concept fluorenyl-benzoate substrate. As described here, photoredox oxidation of the fluorenyl-benzoate follows the same rate constant vs driving force trend determined for thermal MS-CPET. Analogous photoredox catalysis enables C-H activation and H/D exchange in a number of additional substrates with favorably positioned bases. Mechanistic studies support our hypothesis that MS-CPET is a viable pathway for bond activation for substrates in which the C-H bond is weak, while stepwise carboxylate oxidation and hydrogen atom transfer likely predominate for stronger C-H bonds.
Visible responses under high pressure in crystals: phenolphthalein and its analogues with adjustable ring-opening threshold pressures
Deng, Xinyuan,Guo, Hongwei,Meng, Xiao,Wang, Kai,Zou, Bo,Ma, Yuguo
supporting information, p. 4663 - 4666 (2019/05/02)
The ring-opening reaction of phenolphthalein (PP) crystals under hydrostatic pressure provided by using a diamond anvil cell (DAC) is described in this paper for the first time. The color of the crystals changed into red from colorless visibly. The ring-opening threshold pressures could be adjusted by changing the substituent groups. Mechanochromic responses under hydrostatic pressure could also be achieved in polymer blends, which contributes to their practical applications.
Facile synthesis of phthalides from methyl ortho-iodobenzoates and ketones via an iodinemagnesium exchange reaction using a silylmethyl Grignard reagent
Nakamura, Yu,Yoshida, Suguru,Hosoya, Takamitsu
supporting information, p. 858 - 861 (2017/06/13)
Phthalides have been easily prepared by the treatment of methyl o-iodobenzoates with a silylmethyl Grignard reagent in the presence of ketones. The electron-withdrawing ester moiety of methyl o-iodobenzoates and the low nucleophilicity of the silylmethyl Grignard reagent prompted a smooth iodinemagnesium exchange reaction, at room temperature, without affecting the ester moiety or resulting in an undesired reaction with electrophilic ketones. This simple method, wherein special control of the reaction temperature was unnecessary, has allowed the synthesis of various phthalides, including a phenolphthalein derivative.
Domino [Pd]-Catalysis: One-Pot Synthesis of Isobenzofuran-1(3H)-ones
Mahendar, Lodi,Satyanarayana, Gedu
, p. 7685 - 7691 (2016/09/09)
An efficient domino [Pd]-catalysis for the synthesis of isobenzofuran-1(3H)-ones is presented. The strategy shows broad substrate scope and is amenable to o-bromobenzyl tertiary/secondary/primary alcohols. Significantly, the method was applied to the synthesis of antiplatelet drug n-butyl phthalide and cytotoxic agonist 3a-[4′-methoxylbenzyl]-5,7-dimethoxyphthalide.
Domino One-Pot Process for the Synthesis of Isobenzofuran-1(3 H)-ones via [Cu]-Catalysis Using Water as the Green Solvent
Mahendar, Lodi,Satyanarayana, Gedu
, p. 7089 - 7098 (2015/07/28)
An efficient domino one-pot strategy via [Cu]-catalyzed intermolecular "cyanation" of o-bromobenzyl alcohols → in situ intramolecular "nucleophilic attack" → "hydrolysis" is presented, for the synthesis of isobenzofuran-1(3H)-ones. Significantly, the reaction is successfully carried out under environmentally benign conditions, using water as sole green solvent.
Generation and reaction of cyano-substituted aryllithium compounds using microreactors
Nagaki, Aiichiro,Kim, Heejin,Usutani, Hirotsugu,Matsuo, Chika,Yoshida, Jun-Ichi
supporting information; experimental part, p. 1212 - 1217 (2010/06/13)
We developed a microflow method for the generation and reactions of aryllithiums bearing a cyano group, including o-lithiobenzonitrile, m-lithiobenzonitrile and p-lithiobenzonitrile. The method was effective at much higher temperatures than are required for conventional macrobatch reactions, by virtue of rapid mixing, short residence time, and efficient temperature control. In addition, reactions of o-lithiobenzonitrile with carbonyl compounds followed by trapping of the resulting lithium alkoxides with electrophiles were achieved in an integrated microflow system. The Royal Society of Chemistry.
A precipitator for the detection of thiophilic metals in aqua
Dickerson, Tobin J.,Reed, Neal N.,LaClair, James J.,Janda, Kim D.
, p. 16582 - 16586 (2007/10/03)
The detection of toxic metals including mercury and lead has become a vital analytical tool for environmental remediation and regulation of food stocks. A prevalent obstacle with the current assessment of metal ion contamination originates from the lack of adequate assay throughput. In this context, a critical concern with current analyses stems from the fact that the majority of these assays are solution-based, and thus the response is highly dependent upon the assay environment. Herein, we describe a fluorescent dye-doped crystalline assay that offers convincing metal selection and provides detection comparable to conventional solution-based ligands used for the spectrofluorometric analysis of thiophilic heavy metal ions. While comparable in analytical performance to known methodologies, the formation of crystalline analytes provides for signal amplification and, consequently, a powerful platform whose analysis is directly amenable to high-throughput video capture systems. This procedure has been tested in a variety of scenarios and shows good performance using readily available equipment, including a commercially available Universal Serial Bus (USB) CCD camera. Furthermore, when developed in a microcapillary format, this assay is capable of screening thousands of samples per day for the presence of subnanomolar concentrations of Hg2+ using a conventional fluorescence microscope.
Mesityllithium as a reagent for chemoselective halogen-lithium exchange reaction.
Kondo,Asai,Miura,Uchiyama,Sakamoto
, p. 13 - 15 (2007/10/03)
[figure: see text] Mesityllithium was found to be an excellent selective lithiating agent to prepare aryllithium compounds having alkoxycarbonyl groups. To extend our studies on chemoselective lithiation, an important precursor for the synthesis of camptothecin was prepared using a halogen-lithium exchange reaction followed by an intramolecular 1,2-addition.
