345911-45-7Relevant academic research and scientific papers
The redox chemistry of 4-benzoyi-N′-methyipyridinium cations in acetonitrile with and without proton donors: The role of hydrogen bonding
Leventis, Nicholas,Elder, Ian A.,Gao, Xuerong,Bohannan, Eric W.,Sotiriou-Leventis, Chariklia,Rawashdeh, Abdel Monem M.,Overschmidt, Travis J.,Gaston, Kimberly R.
, p. 3663 - 3674 (2001)
In anhydrous CH3CN, 4-benzoyl-W-methyIpyridinium cations undergo two reversible, well-separated (ΔE1/2 ～ 0.6 V) one-electron reductions in analogy to quinones and viologens. If the solvent contains weak protic acids, such as water or alcohols, the first cyclic voltammetric wave remains unaffected while the second wave is shifted closer to the first. Both voltammetric and spectroelectrochemical evidence suggest that the positive shift of the second wave is due to hydrogen bonding between the two-electron reduced form of the ketone and the proton donors. While the one-electron reduction product is stable both in the presence and in the absence of the weak-acid proton donors, the two-electron reduction wave is reversible only in the time scale of cyclic voltammetry. Interestingly, at longer times, the hydrogen bonded adduct reacts further giving nonquaternized 4-benzoylpyridine and 4-(a-hydroxybenzyl)pyridine as the two main terminal products. In the presence of stronger acids, such as acetic acid, the second wave merges quickly with the first, producing an irreversible two-electron reduction wave. The only terminal product in this case is the quatemized 4-(α-hydroxybenzyl)-N-methyIpyridinium cation. Experimental evidence points toward a common mechanism for the formation of the nonquaternized products in the presence of weaker acids and the quaternized product in the presence of CH3CO2H.
Metal-free oxidative: Para -acylation of unprotected anilines with N-heteroarylmethanes
Liu, Min,Chen, Xue,Chen, Tieqiao,Xu, Qing,Yin, Shuang-Feng
, p. 9845 - 9854 (2017/12/08)
A selective oxidative para-acylation of unprotected anilines with methyl groups in N-heteroarylmethanes was achieved. This transformation proceeds under mild metal-free reaction conditions to produce the corresponding valuable diarylmethanones in good to high yields, featuring high site-selectivity, high functional-group-tolerance, gram-scale synthesis and easy product-derivation. Preliminary mechanistic studies revealed that the present oxidative para-acylation would take place via a Friedel-Crafts-type process of in situ imines and the steric hindrance might be the key issue for the high regio-selectivity.
