626-55-1Relevant articles and documents
Catalyst-Free N-Deoxygenation by Photoexcitation of Hantzsch Ester
Cardinale, Luana,Jacobi Von Wangelin, Axel,Konev, Mikhail O.
supporting information, (2020/02/15)
A mild and operationally simple protocol for the deoxygenation of a variety of heteroaryl N-oxides and nitroarenes has been developed. A mixture of substrate and Hantzsch ester is proposed to result in an electron donor-acceptor complex, which upon blue-light irradiation undergoes photoinduced electron transfer between the two reactants to afford the products. N-oxide deoxygenation is demonstrated with 22 examples of functionally diverse substrates, and the chemoselective reduction of nitroarenes to the corresponding hydroxylamines is also shown.
Base-catalyzed aryl halide isomerization enables the 4-selective substitution of 3-bromopyridines
Bandar, Jeffrey S.,Puleo, Thomas R.
, p. 10517 - 10522 (2020/10/18)
The base-catalyzed isomerization of simple aryl halides is presented and utilized to achieve the 4-selective etherification, hydroxylation and amination of 3-bromopyridines. Mechanistic studies support isomerization of 3-bromopyridines to 4-bromopyridines proceedsviapyridyne intermediates and that 4-substitution selectivity is driven by a facile aromatic substitution reaction. Useful features of a tandem aryl halide isomerization/selective interception approach to aromatic functionalization are demonstrated. Example benefits include the use of readily available and stable 3-bromopyridines in place of less available and stable 4-halogenated congeners and the ability to converge mixtures of 3- and 5-bromopyridines to a single 4-substituted product.
A Practical and Robust Multistep Continuous Process for Manufacturing 5-Bromo-N-(tert-butyl)pyridine-3-sulfonamide
Yu, Miao,Strotman, Neil A.,Savage, Scott A.,Leung, Simon,Ramirez, Antonio
, p. 2088 - 2095 (2019/10/08)
A multistep continuous flow process involving (1) magnesium-halogen exchange, (2) sulfonylation with sulfuryl chloride, and (3) reaction with tert-butylamine was developed for the synthesis of an arylsulfonamide pharmaceutical intermediate in the synthesis of BMS-919373. The process was successfully implemented, including a robust control strategy to manage the levels of several process impurities, to produce 76 kg of 5-bromo-N-(tert-butyl)pyridine-3-sulfonamide (2). As the instability of the reactive intermediates and existence of strong exotherms made a batch process unsuitable for production beyond a 1 kg scale, the alternative continuous process led to a practical and robust manufacturing route to the active pharmaceutical ingredient.