39148-55-5Relevant academic research and scientific papers
Time-resolved EPR and laser photolysis investigations of photoinduced ω-bond dissociation in an aromatic carbonyl compound having triplet π,π* character
Yamaji, Minoru,Inomata, Susumu,Nakajima, Satoru,Akiyama, Kimio,Tero-Kubota, Shozo,Tobita, Seiji,Marciniak, Bronislaw
, p. 211 - 216 (2006)
Photochemical properties of photoinduced ω-bond dissociation in p-phenylbenzoylbenzyl phenyl sulfide (PPS) having the lowest triplet state (T1) of π,π* character in solution were investigated by time-resolved EPR and laser flash photolysis techniques. PPS was found to undergo photoinduced ω-bond cleavage in the excited lowest singlet state (S1(n,π*)) with a quantum yield (Φrad) of 0.15 for the radical formation, which was independent of excitation wavelengths. Based on the facts of the observation of the absorption spectrum of triplet PPS upon triplet sensitization of xanthone, and absence of CIDEP signal, ω-cleavage was shown to be absent in the T1(π,π*) state of PPS. Considering the electronic character of the excited and dissociative states of PPS, a schematic energy diagram for the ω-bond dissociation of PPS was shown.
Evaluation of Cyclic Amides as Activating Groups in N-C Bond Cross-Coupling: Discovery of N-Acyl-δ-valerolactams as Effective Twisted Amide Precursors for Cross-Coupling Reactions
Bisz, Elwira,Chen, Hao,Dziuk, B?a?ej,Ejsmont, Krzysztof,Lalancette, Roger,Pyle, Daniel J.,Rahman, Md. Mahbubur,Szostak, Michal,Szostak, Roman,Wang, Qi
, p. 10455 - 10466 (2021/07/31)
The development of efficient methods for facilitating N-C(O) bond activation in amides is an important objective in organic synthesis that permits the manipulation of the traditionally unreactive amide bonds. Herein, we report a comparative evaluation of a series of cyclic amides as activating groups in amide N-C(O) bond cross-coupling. Evaluation of N-acyl-imides, N-acyl-lactams, and N-acyl-oxazolidinones bearing five- and six-membered rings using Pd(II)-NHC and Pd-phosphine systems reveals the relative reactivity order of N-activating groups in Suzuki-Miyaura cross-coupling. The reactivity of activated phenolic esters and thioesters is evaluated for comparison in O-C(O) and S-C(O) cross-coupling under the same reaction conditions. Most notably, the study reveals N-acyl-δ-valerolactams as a highly effective class of mono-N-acyl-activated amide precursors in cross-coupling. The X-ray structure of the model N-acyl-δ-valerolactam is characterized by an additive Winkler-Dunitz distortion parameter ?(τ+χN) of 54.0°, placing this amide in a medium distortion range of twisted amides. Computational studies provide insight into the structural and energetic parameters of the amide bond, including amidic resonance, N/O-protonation aptitude, and the rotational barrier around the N-C(O) axis. This class of N-acyl-lactams will be a valuable addition to the growing portfolio of amide electrophiles for cross-coupling reactions by acyl-metal intermediates.
Carbonylative Suzuki-Miyaura Coupling Reactions of Aryl Iodides with Readily Available Polymer-Immobilized Palladium Nanoparticles
Yasukawa, Tomohiro,Zhu, Zhiyuan,Yamashita, Yasuhiro,Kobayashi, Shu
, p. 502 - 504 (2020/09/21)
Polysilane/alumina-supported palladium nanoparticle catalyzed carbonylative Suzuki-Miyaura coupling reactions under ligand-free conditions have been developed to synthesize diaryl ketones. High yields and selectivities were achieved even with low catalyst loading under atmospheric pressure of CO gas. A variety of aryl iodides and arylboronic acids could be utilized to afford the diaryl ketones in excellent yields. Moreover, the ligand-free immobilized palladium nanoparticles could be recovered by simple filtration and the catalytic activity could be maintained for several runs.
Silylcarboxylic Acids as Bifunctional Reagents: Application in Palladium-Catalyzed External-CO-Free Carbonylative Cross-Coupling Reactions
Li, Xiong,Xu, Jie,Li, Yue,Kramer, S?ren,Skrydstrup, Troels,Lian, Zhong
, p. 4078 - 4083 (2020/07/30)
A palladium-catalyzed external-CO-free carbonylative Hiyama-Denmark cross-coupling reaction is presented. The introduction of silylcarboxylic acids as bifunctional reagents (CO and nucleophile source) avoids the need for external gaseous CO and a silylarene coupling partner. The transformation features high functional group tolerance and it is successful with electron-rich, -neutral, and -poor aryl iodides. Stoichiometric studies and control experiments provide insight into the reaction mechanism and support the hypothesized dual role of silylcarboxylic acids. (Figure presented.).
Benzophenones as xanthone-open model CYP11B1 inhibitors potentially useful for promoting wound healing
Gobbi, Silvia,Hu, Qingzhong,Foschi, Giacomo,Catanzaro, Elena,Belluti, Federica,Rampa, Angela,Fimognari, Carmela,Hartmann, Rolf W.,Bisi, Alessandra
, p. 401 - 409 (2019/02/15)
The inhibition of steroidogenic cytochrome P450 enzymes has been shown to play a central role in the management of life-threatening diseases such as cancer, and indeed potent inhibitors of CYP19 (aromatase) and CYP17 (17α hydroxylase/17,20 lyase) are curr
Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols
Verheyen, Thomas,Van Turnhout, Lars,Vandavasi, Jaya Kishore,Isbrandt, Eric S.,De Borggraeve, Wim M.,Newman, Stephen G.
supporting information, (2019/05/08)
An intermolecular coupling of primary alcohols and organotriflates has been developed to provide ketones by the action of a Ni(0) catalyst. This oxidative transformation is proposed to occur by the union of three distinct catalytic cycles. Two competitive oxidation processes generate aldehyde in situ via hydrogen transfer oxidation or (pseudo)dehalogenation pathways. As aldehyde forms, a Ni-catalyzed carbonyl-Heck process enables formation of the key carbon-carbon bond. The utility of this rare alcohol to ketone transformation is demonstrated through the synthesis of diverse complex and bioactive molecules.
Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols
Verheyen, Thomas,Van Turnhout, Lars,Vandavasi, Jaya Kishore,Isbrandt, Eric S.,De Borggraeve, Wim M.,Newman, Stephen G.
supporting information, p. 6869 - 6874 (2019/05/10)
An intermolecular coupling of primary alcohols and organotriflates has been developed to provide ketones by the action of a Ni(0) catalyst. This oxidative transformation is proposed to occur by the union of three distinct catalytic cycles. Two competitive oxidation processes generate aldehyde in situ via hydrogen transfer oxidation or (pseudo)dehalogenation pathways. As aldehyde forms, a Ni-catalyzed carbonyl-Heck process enables formation of the key carbon-carbon bond. The utility of this rare alcohol to ketone transformation is demonstrated through the synthesis of diverse complex and bioactive molecules.
Synthesis of arylketones using Envirocat EPZG catalyst
Ghatpande, Sonali,Mahajan, Supriya
, p. 188 - 192 (2007/10/03)
The Friedel-Crafts acylation reactions of substituted benzene derivatives with substituted acid chlorides proceed smoothly in the presence of a catalytic amount of Envirocat EPZG, a novel supported reagent catalyst, based on montmorillonite K10 clay. This catalyst is eco-friendly, selective and reusable and hence provides a safer and a cost effective approach for large-scale production in industries. The present work involves synthesis of fifteen ketones by using fresh and reused Envirocat EPZG catalyst and a conventional catalyst for Friedel-Crafts reaction, anhyd. AlCl3. The yields of ketones with fresh Envirocat EPZG are always more than that obtained with anhyd. AlCl3. Envirocat EPZG has been reused for the number of reactions in a series, without much loss in its efficiency. Ketones having activating as well as deactivating groups on benzene ring have been synthesized in satisfactory yields.
Triplet energy distribution in photoinitiators containing two dissociable groups
Shah, Bipin K.,Neckers, Douglas C.
, p. 6117 - 6123 (2007/10/03)
Suitable probe molecules containing the benzophenone chromophore and one dissociable bond [perester 1 or C-X (4, 5)] or two such bonds (2, 3) have been synthesized and studied to examine intramolecular triplet energy dispersion. Triplet energies and phosphorescence quantum yields as well as quantum efficiencies of bond scissions have been studied, and the flow of triplet energy in such molecules is discussed. Upon irradiation at 350 nm in either benzene or methanol, the target peresters undergo dissociation of both cleavable groups, producing a pair of radicals. The presence of a benzylic chloride function has little influence on the efficiency of perester dissociation. However, the presence of a benzylic bromide function was found to decrease the quantum yield of decomposition of the perester function of 3. This can be explained by taking into account the effect of the heavy atom and the rate of cage geminate radical pair recombination. The nature of the heavy atom perturbation, however, was found to be different in 5 as compared with 3.
Syntheses of Asymmetrical Diaryl and Aryl Alkyl Ketones as Possible Non-steroidal Antiprogestational Agents
Kumar, Shiv,Seth, M.,Bhaduri, A. P.,Agnihotri, Anila,Srivastava, A. K.
, p. 154 - 157 (2007/10/02)
A number of asymmetrical diaryl and aryl alkyl ketones have been synthesised as possible non-steroidal antiprogestational agents.Evaluation of these compounds as competitive inhibitors of progesterone binding to uterine cytosol progesterone receptors of rabbit and human indicates that 3-methyl-4'-phenylbenzophenone (2) exhibits marginal activity in both the cases.However, this compound has been found to be inferior to R 5020 and d-norgestrel.
