37941-24-5Relevant academic research and scientific papers
The Stronger the Better: Donor Substituents Push Catalytic Activity of Molecular Chromium Olefin Polymerization Catalysts
Enders, Markus,Hansen, Helge-Boj,Wadepohl, Hubert
supporting information, p. 11084 - 11093 (2021/06/27)
The donor strength of bifunctional pyridine-cyclopentadienyl ligands was altered systematically by the introduction of donating groups in the para-position of the pyridine. In the resulting chromium complexes an almost linear correlation between donor str
Amination of Aromatic Halides and Exploration of the Reactivity Sequence of Aromatic Halides
Yang, Chu,Zhang, Feng,Deng, Guo-Jun,Gong, Hang
, p. 181 - 190 (2019/01/10)
A base-promoted amination of aromatic halides has been developed using a limited amount of dimethylformamide (DMF) or amine as an amino source. Various aryl halides, including F, Cl, Br, and I, have been successfully aminated in good to excellent yields. Although the amination of aromatic halides with amines or DMF is usually considered as an aromatic nucleophilic substitution (SNAr) process, and the reactivity of an aromatic halide is F > Cl > Br > I, the reactivity of aromatic halides in this system was found to be I > Br a‰ F > Cl. This protocol also showed a good regioselectivity for multihalogenated aromatics. This protocol is valuable for industrial application due to the simplicity of operation, the unrestricted availability of amino sources and aromatic halides, transition metal-free conditions, no requirement for solvent, and scalability.
Flow synthesis of 2-methylpyridines via α-methylation
Manansala, Camille,Tranmer, Geoffrey K.
, p. 15797 - 15806 (2015/12/01)
A series of simple 2-methylpyridines were synthesized in an expedited and convenient manner using a simplified bench-top continuous flow setup. The reactions proceeded with a high degree of selectivity, producing α-methylated pyridines in a much greener fashion than is possible using conventional batch reaction protocols. Eight 2-methylated pyridines were produced by progressing starting material through a column packed with Raney nickel using a low boiling point alcohol (1-propanol) at high temperature. Simple collection and removal of the solvent gave products in very good yields that were suitable for further use without additional work-up or purification. Overall, this continuous flow method represents a synthetically useful protocol that is superior to batch processes in terms of shorter reaction times, increased safety, avoidance of work-up procedures, and reduced waste. A brief discussion of the possible mechanism(s) of the reaction is also presented which involves heterogeneous catalysis and/or a Ladenberg rearrangement, with the proposed methyl source as C1 of the primary alcohol.
Convenient procedure for the α-methylation of simple pyridines
Broering, Martin,Kleeberg, Christian
scheme or table, p. 3672 - 3682 (2009/04/03)
A convenient and straightforward laboratory procedure is presented for a highly selective mono-α-methylation of pyridines without reactive functional groups. The methylating agent is probably carbon monoxide/dihydrogen generated in situ from a high-boiling alcohol on a metal surface. The reaction is catalyzed by a Raney nickel catalyst at ambient pressure, which renders the protocol practicable in standard organic laboratories. The intrinsically high reaction temperature and long reaction times restrict the application to pyridine derivatives with less reactive substituents. The outcome of the reaction can be rationalized by the assumption of a simple heterogeneous mechanism. Copyright Taylor & Francis Group, LLC.
Pyridine compounds and their pharmaceutical use
-
, (2008/06/13)
A compound of formula (I) wherein each symbol is as defined in the specification, and pharmaceutically acceptable salts thereof. The compound (I) of the present invention and pharmaceutically acceptable salts thereof possess a strong inhibitory activity on the production of nitric oxide (NO), and are useful for prevention and/or treatment of NOS(nitric oxide synthasey)-mediated diseases such as adult respiratory distress syndrome, myocarditis, synovitis, septic shock, insulin-ependent diabetes mellitus, ulcerative colitis, cerebral infarction, rheumatoid arthritis, osteoarthritis, osteoporosis, systemic lupus erythematosus, rejection by organ transplantation, asthma, pain, ulcer, and the like in human being and animals.
Atropisomeric α-methyl substituted analogues of 4-(dimethylamino)pyridine: Synthesis and evaluation as acyl transfer catalysts
Spivey,Maddaford,Leese,Redgrave
, p. 1785 - 1794 (2007/10/03)
The regioselectivity of α-metalation-methylation of N-BF3 adducts of 4-(dimethylamino)pyridines as a function of β-substitution is examined in attempts to prepare configurationally stable atropisomeric derivatives (I and II) having an α-methyl substituent and a β-biaryl stereogenic axis. The activity of some of these derivatives as catalysts for acyl transfer is examined and the kinetic resolution of 1-(1-naphthyl)ethanol catalysed by α-methyl chiral DMAP (-)-24 is reported. A rationale for the reduced stereoselectivity of this catalyst relative to its non-α-substituted analogue (-)-1 is also proposed.
