18103-78-1Relevant academic research and scientific papers
Precious metal complexes of bis(pyridyl)allenes: Synthesis and catalytic and medicinal applications
Arnau Del Valle, Carla,Maliszewska, Hanna K.,Marín, María J.,Mu?oz, María Paz,Waller, Zo? A. E.,Xia, Ying
, p. 16739 - 16750 (2021/12/08)
The incorporation of donor-type substituents on the allene core opens up the possibility of coordination complexes in which the metal is bonded to the donor groups, with or without interaction with the double bond system. Despite the challenges in the syn
Visible-light-initiated catalyst-free oxidative cleavage of (Z)-triaryl-substituted alkenes containing pyridyl motif under ambient conditions
Chen, Hua,Fu, Haiyan,Ge, Yicen,Li, Ruixiang,Li, Shun,Li, Wenjing,Luo, Lihua,Xu, Jiaqi,Yuan, Maolin,Zheng, Xueli
supporting information, p. 3649 - 3655 (2021/06/06)
The catalyst-free oxidative cleavage of (Z)-triaryl-substituted alkenes bearing a pyridyl motif in ambient air under the irradiation of blue LEDs at room temperature has been developed. The reaction was facile and scalable, and proceeded with good functional group tolerance, affording pharmaceutically useful 2-acyl pyridines. The electron paramagnetic resonance (EPR) studies together with control experiments showed that the singlet oxygen (1O2) and superoxide anion (O2˙?) are the reactive oxidants. The1O2generation mechanism correlated well with the photophysical properties of the substrate (Z)-triaryl-substituted alkenes, the excited state of which was proved to serve as the triplet sensitizer for the generation of1O2
Rhodium-Catalyzed Pyridine N-Oxide Assisted Suzuki-Miyaura Coupling Reaction via C(O)-C Bond Activation
Zhong, Jing,Long, Yang,Yan, Xufei,He, Shiyu,Ye, Runyou,Xiang, Haifeng,Zhou, Xiangge
supporting information, p. 9790 - 9794 (2019/12/24)
A rhodium-catalyzed Suzuki-Miyaura coupling reaction via C(O)-C bond activation to form 2-benzoylpyridine N-oxide derivatives is reported. Both the C(O)-C(sp2) and C(O)-C(sp3) bond could be activated during the reaction with yields up to 92%. The N-oxide moiety could be employed as a traceless directing group, leading to free pyridine ketones.
Photoinduced Divergent Alkylation/Acylation of Pyridine N-Oxides with Alkynes under Anaerobic and Aerobic Conditions
Xu, Jin-Hui,Wu, Wen-Bin,Wu, Jie
supporting information, p. 5321 - 5325 (2019/07/08)
Ortho-alkylated and ortho-acylated pyridines have been conveniently synthesized from pyridine N-oxides and alkynes under visible-light-mediation in a metal-free manner. The alkynes served as both alkylating and acylating agents via switching between anaerobic and aerobic conditions. The overall strategy accommodates a broad scope of substituted pyridine N-oxides and alkynes, with excellent regioselectivity in a number of cases.
Room Temperature Metal-Catalyzed Oxidative Acylation of Electron-Deficient Heteroarenes with Alkynes, Its Mechanism, and Application Studies
Sharma, Shweta,Kumar, Mukesh,Vishwakarma, Ram A.,Verma, Mahendra K.,Singh, Parvinder Pal
, p. 12420 - 12431 (2018/10/20)
Herein, we report an original one-step, simple, room-temperature, regioselective Minisci reaction for the acylation of electron-deficient heteroarenes with alkynes. The method has broad functional group compatibility and gives exclusively monoacylated products in good to excellent yields. The mechanistic pathway was analyzed based on a series of experiments confirming the involvement of a radical pathway. The 18O-labeling experiment suggested that water is a source of oxygen in the acylated product, and head space GC-MS experiment shows the C-C cleavage occurs via release as CO2.
Transformation of Carbonyl Compounds into Homologous Alkynes under Neutral Conditions: Fragmentation of Tetrazoles Derived from Cyanophosphates
Yoneyama, Hiroki,Numata, Masahiro,Uemura, Kenji,Usami, Yoshihide,Harusawa, Shinya
, p. 5538 - 5556 (2017/06/07)
Cyanophosphates (CPs) can be easily prepared from either ketones or aldehydes, and their reaction with NaN3-Et3N·HCl results in the formation of azidotetrazoles. Under microwave irradiation, successive fragmentation of the azidotetrazoles generates alkylidene carbenes that undergo [1,2]-rearrangement and are transformed into homologous alkynes. Treatment of ketone-derived CPs with TMSN3 and Bu2SnO as catalyst in toluene at reflux directly yields the corresponding internal alkynes, whereas the reaction of aldehyde-derived CPs with NaN3-Et3N·HCl in THF at reflux or TMSN3-Bu2SnO (cat.) in toluene at reflux provides homologous terminal alkynes in good yields. These reactions take place under neutral conditions and can be successfully extended to obtain alkynes that are not usually accessible from the corresponding carbonyl compounds by the Ohira-Bestmann or Shioiri procedures, which require basic conditions.
Efficient Selenium-Catalyzed Selective C(sp3)?H Oxidation of Benzylpyridines with Molecular Oxygen
Jin, Weiwei,Zheng, Poonnapa,Wong, Wing-Tak,Law, Ga-Lai
, p. 1588 - 1593 (2017/05/05)
An efficient selenium-catalyzed direct oxidation of benzylpyridines in aqueous DMSO has been successfully developed by using molecular oxygen as the oxidant. A variety of benzoylpyridines with broad functional group tolerance were obtained in modest to excellent yields and with exclusive chemoselectivity. (Figure presented.).
Generation and reactions of pyridyllithiums via Br/li exchange reactions using continuous flow microreactor systems
Nagaki, Aiichiro,Yamada, Daisuke,Yamada, Shigeyuki,Doi, Masatomo,Ichinari, Daisuke,Tomida, Yutaka,Takabayashi, Naofumi,Yoshida, Jun-Ichi
, p. 199 - 207 (2013/03/28)
A continuous flow microreactor method for generating and carrying out reactions on pyridyllithiums has been developed based on Br/Li exchange reactions of bromopyridines and dibromopyridines. The reactions can be carried out without using cryogenic conditions by virtue of short residence times and efficient heat transfer, while very low temperatures such as-78 or-110°C are required for conventional batch macro methods. Moreover, sequential introduction of two different electrophiles has been successfully achieved using dibromopyridines in an integrated flow microreactor system composed of four micromixers and four microtube reactors.
Flow microreactor synthesis of disubstituted pyridines from dibromopyridines via Br/Li exchange without using cryogenic conditions
Nagaki, Aiichiro,Yamada, Shigeyuki,Doi, Masatomo,Tomida, Yutaka,Takabayashi, Naofumi,Yoshida, Jun-Ichi
, p. 1110 - 1113 (2011/06/26)
A flow microreactor method for the synthesis of disubstituted pyridines by generation of pyridyllithiums followed by reactions with electrophiles has been developed. By using a short residence time and efficient temperature control, the cryogenic conditions required for conventional batch macro processes can be avoided. Sequential introduction of two different electrophiles into dibromopyridines has been achieved using an integrated flow microreactor system composed of four micromixers and four microtube reactors, to obtain disubstituted pyridine compounds.
Synthesis of optically active imidazopyridinium salts and the corresponding NHCs
Schmidt, Michael A.,Movassaghi, Mohammad
, p. 101 - 104 (2007/10/03)
A convergent synthesis of chiral imidazo-[1,5-a]-pyridinium salts is described by facile introduction of a stereogenic center via the N2 substituent. Conversion of these optically active salts to the corresponding N-heterocyclic carbenes (NHCs) and their trapping with sulfur followed by optical activity measurements are discussed.
