Efficient [WO4]2鈥?/sup>-Catalyzed Chemical Fixation of Carbon Dioxide with 2-Aminobenzonitriles to Quinazoline-2,4(1H,3H)-diones

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• 作者：Toshihiro Kimura ; Hanako Sunaba ; Keigo Kamata ; Noritaka Mizuno
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：December 3, 2012
• 年：2012
• 卷：51
• 期：23
• 页码：13001-13008
• 全文大小：428K
• 年卷期：v.51,no.23(December 3, 2012)
• ISSN：1520-510X

文摘

A simple monomeric tungstate, TBA₂[WO₄] (I, TBA = tetra-n-butylammonium), could act as an efficient homogeneous catalyst for chemical fixation of CO₂ with 2-aminobenzonitriles to quinazoline-2,4(1H,3H)-diones. Various kinds of structurally diverse 2-aminobenzonitriles could be converted into the corresponding quinazoline-2,4(1H,3H)-diones in high yields at atmospheric pressure of CO₂. Reactions of inactive 2-amino-4-chlorobenzonitrile and 2-amino-5-nitrobenzonitrile at 2 MPa of CO₂ also selectively proceeded. The present system was applicable to a g-scale reaction of 2-amino-5-fluorobenzonitrile (10 mmol scale) with CO₂ and 1.69 g of analytically pure quinazoline-2,4(1H,3H)-dione could be isolated. In this case, the turnover number reached up to 938 and the value was the highest among those reported for base-mediated systems so far. NMR spectroscopies showed formation of the corresponding carbamic acid through the simultaneous activation of both 2-aminobenzonitirile and CO₂ by I. Kinetic and computational studies revealed that I plays an important role in conversion of the carbamic acid into the product.