57954-94-6Relevant articles and documents
Design of High-Performance Pyridine/Quinoline Hydrazone Photoswitches
Mravec, Bernard,Budzák, ?imon,Medved', Miroslav,Pa?teka, Luká? F.,Slavov, Chavdar,Sa?mannshausen, Torben,Wachtveitl, Josef,Ko?í?ek, Jozef,Hegedüsová, Lea,Filo, Juraj,Cigáň, Marek
, p. 11633 - 11646 (2021/08/20)
The design of P-type photoswitches with thermal stability of the metastable form of hundreds of years that would efficiently transform using excitation wavelengths above 350 nm remains a challenge in the field of photochromism. In this regard, we designed and synthesized an extended set of 13 pyridine/quinoline hydrazones and systematically investigated the structure-property relationships, defining their kinetic and photoswitching parameters. We show that the operational wavelengths of the pyridine hydrazone structural motif can be effectively shifted toward the visible region without simultaneous loss of their high thermal stability. Furthermore, we characterized the ground-state and excited-state potential energy surfaces with quantum-chemical calculations and ultrafast transient absorption spectroscopy, which allowed us to rationalize both the thermal and photochemical reaction mechanisms of the designed hydrazones. Whereas introducing an electron-withdrawing pyridyl moiety in benzoylpyridine hydrazones leads to thermal stabilities exceeding 200 years, extended π-conjugation in naphthoylquinoline hydrazones pushes the absorption maxima toward the visible spectral region. In either case, the compounds retain highly efficient photoswitching characteristics. Our findings open a route to the rational design of a new family of hydrazone-based P-type photoswitches with high application potential in photonics or photopharmacology.
Copper-Catalyzed Aerobic Oxygenation of Benzylpyridine N-Oxides and Subsequent Post-Functionalization
Sterckx, Hans,Sambiagio, Carlo,Médran-Navarrete, Vincent,Maes, Bert U. W.
supporting information, p. 3226 - 3236 (2017/09/13)
A copper-catalyzed aerobic oxidation of benzylpyridine N-oxides is reported. The N-oxide moiety acts as a built-in activator for the benzylic methylene oxidation, without requirement of additives. Reaction conditions were identified which suppress undesired benzoylpyridine formation via N-deoxygenation involving intermolecular oxygen transfer. The versatility of the N-oxide group of the benzoylpyridine N-oxide reaction products for post-functionalization of the pyridine ring is demonstrated through efficient C–C, C–N, C–O and C–Cl bond forming procedures, with both nucleophiles and electrophiles. Finally, the applicability of the new synthetic methodology is demonstrated in an alternative route towards the antihistaminic drug Acrivastine via three consecutive N-oxide activated C–H functionalization processes, starting from picoline N-oxide. (Figure presented.).
A Nitrogen-Assisted One-Pot Heteroaryl Ketone Synthesis from Carboxylic Acids and Heteroaryl Halides
Demkiw, Krystyna,Araki, Hirofumi,Elliott, Eric L.,Franklin, Christopher L.,Fukuzumi, Yoonjoo,Hicks, Frederick,Hosoi, Kazushi,Hukui, Tadashi,Ishimaru, Yoichiro,O'Brien, Erin,Omori, Yoshimasa,Mineno, Masahiro,Mizufune, Hideya,Sawada, Naotaka,Sawai, Yasuhiro,Zhu, Lei
, p. 3447 - 3456 (2016/05/19)
A practical and highly effective one-pot synthesis of versatile heteroaryl ketones directly from carboxylic acids and heteroaryl halides under mild conditions is reported. This method does not require derivatization of carboxylic acids (preparation of acid chlorides, Weinreb amides, etc.) or the use of any additives/catalysts. A wide substrate scope of carboxylic acids with high functional group tolerance has also been demonstrated. The results reveal that the presence of an α-nitrogen on the halide substrate greatly improves the desired ketone formation.
