A novel ionic liquid mediated synthesis of 4(1H)-quinolones, 5H-thiazolo[3,2-a]pyrimidin-5-one and 4H-pyrimido[2,1-b]benzothiazol-4-ones

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• 作者：Ashok K. Yadav ; ^{drakyada@yahoo.co.in} ; Gopi Ram Sharma ; Pankaj Dhakad ; Tripti Yadav
• 关键词：Thiazoles ; Cyclization ; Ionic liquid
• 刊名：Tetrahedron Letters
• 出版年：2012
• 出版时间：15 February, 2012
• 年：2012
• 卷：53
• 期：7
• 页码：859-862
• 全文大小：215 K

文摘

A new, convenient, environmentally benign two-step synthesis of 4(1H)-quinolones, 5H-thiazolo[3,2-a]pyrimidin-5-one and 4H-pyrimido[2,1-b]benzothiazol-4-ones have been developed by first condensing substituted arylamine/2-aminothiazole/2-aminobenzenethiazole with Meldrum¡¯s acid and trimethylorthoformate in 1-butyl-3-methylimidazolium bromide at a moderate temperature to afford 5-{(substituted aryl/4-methylthiazolyl/substituted benzothiazolyl)methylene}-2,2-dimethyl-1,3-dioxane-4,6-dione. The resulting compounds upon cyclization in 1-butyl-3-methyl tetrafluoroborate/triflate at a moderate temperature gave the title compounds in excellent yields.