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Communication | Regular issue | Vol 96, No. 11, 2018, pp.1889-1895
Published online, 19th November, 2018
DOI: 10.3987/COM-18-13988
New Facile Synthesis of 3-Substituted 7,8-Dihydroquinolin-5(6H)-ones and [1]Benzopyrano[4,3-b]pyridin-5-ones Using 2-(Hetero)arylvinamidinium Salts

Yiyi Weng, Chen Sun, Qingwei Cao, Hantao Chen, Nanhui Li, Zhuo Chen, and Weike Su*

*Collaborative Innovation Center of Yangtze River Delta Region Green of Pharmaceuticals, Zhejiang University of Technology, Hangzhou 310014, China

Abstract

The method of cyclocondensation of 3-amino-2-cyclohexen-1-ones 2 or 4-aminocoumarin 3 with symmetrical 2-(hetero)aryl-vinamidinium salts 1 has been developed, providing an efficient synthetic pathway to access novel functionalized 3-substituted 7,8-dihydroquinolin-5(6H)-ones 4 or [1]benzopyrano[4,3-b]pyridin-5-ones 5 in good to excellent yields. All the aryl-substituted and heterocyclic-substituted vinamidinium salts undergo a facile electrocyclic ring closure to form pyridine ring with α,β-unsaturated ketones. A possible mechanism for the formation of pyridine ring is proposed.