5661-00-7Relevant articles and documents
Reaction of Aldehydes/Ketones with Electron-Deficient 1,3,5-Triazines Leading to Functionalized Pyrimidines as Diels-Alder/Retro-Diels-Alder Reaction Products: Reaction Development and Mechanistic Studies
Yang, Kai,Dang, Qun,Cai, Pei-Jun,Gao, Yang,Yu, Zhi-Xiang,Bai, Xu
, p. 2336 - 2344 (2017/03/11)
Catalytic inverse electron demand Diels-Alder (IEDDA) reactions of heterocyclic aza-dienes are rarely reported since highly reactive and electron-rich dienophiles are often found not compatible with strong acids such as Lewis acids. Herein, we disclose that TFA-catalyzed reactions of electron-deficient 1,3,5-triazines and electron-deficient aldehydes/ketones can take place. These reactions led to highly functionalized pyrimidines as products in fair to good yields. The reaction mechanism was carefully studied by the combination of experimental and computational studies. The reactions involve a cascade of stepwise inverse electron demand hetero-Diels-Alder (ihDA) reactions, followed by retro-Diels-Alder (rDA) reactions and elimination of water. An acid was required for both ihDA and rDA reactions. This mechanism was further verified by comparing the relative reactivity of aldehydes/ketones and their corresponding vinyl ethers in the current reaction system.
Mechanistic aspect of ring transformations in the reaction of 5-nitro-4-pyrimidinone with acetophenone derivatives and cycloalkanones depending on the electron density/ring size of the ketone
Nishiwaki, Nagatoshi,Sugimoto, Ryuichi,Saigo, Kazuhiko,Kobiro, Kazuya
supporting information, p. 956 - 959 (2013/03/13)
3-Methyl-5-nitro-4-pyrimidinone undergoes two kinds of nucleophilic type ring transformations upon treatment with cycloalkanones in the presence of ammonium acetate, which affords 4,5-disubstituted pyrimidines and 5,6-disubstituted 3-nitro-2-pyridones. In order to improve the synthetic utility of this reaction, it is necessary to control the regioselectivity of these ring transformations. In the present work, we performed DFT calculation to realize the selectivity of two ring transformation products. In cases of adduct intermediates derived from cyclohexanone and cyclooctanone, the 2-attack proceeds preferably to give condensed pyrimidines. On the other hand, the adduct intermediate derived from cycloheptanone undergoes the 4-attack predominantly to afford condensed nitropyridone.
One-step synthesis of 4,5-disubstituted pyrimidines using commercially available and inexpensive reagents
Baran, Phil S.,Shenvi, Ryan A.,Nguyen, Steven A.
, p. 581 - 586 (2008/02/02)
4,5-Disubstituted pyrimidines are synthesized from the corresponding ketone in one-step using inexpensive reagents (formamidine acetate, n-propanol, heat). Contrasted to other methods, this process appears quite amenable to large-scale use in industrial settings.
