title: Efficient [WO4](2-)-catalyzed chemical fixation of carbon dioxide with 2-aminobenzonitriles to quinazoline-2,4(1H,3H)-diones.
abstract: A simple monomeric tungstate, TBA(2)[WO(4)] (I, TBA = tetra-n-butylammonium), could act as an efficient homogeneous catalyst for chemical fixation of CO(2) 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 CO(2). Reactions of inactive 2-amino-4-chlorobenzonitrile and 2-amino-5-nitrobenzonitrile at 2 MPa of CO(2) also selectively proceeded. The present system was applicable to a g-scale reaction of 2-amino-5-fluorobenzonitrile (10 mmol scale) with CO(2) 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 CO(2) by I. Kinetic and computational studies revealed that I plays an important role in conversion of the carbamic acid into the product.
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kimura
authors.forename: Hanako
authors.initials: H
authors.lastname: Sunaba
authors.forename: Keigo
authors.initials: K
authors.lastname: Kamata
authors.forename: Noritaka
authors.initials: N
authors.lastname: Mizuno
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D002384:Catalysis; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D052999:Quinazolinones / Q000138:chemical synthesis* / Q000737:chemistry; D017973:Tungsten Compounds / Q000737:chemistry*
chemical_list: D009570:Nitriles; D009942:Organometallic Compounds; D000644:Quaternary Ammonium Compounds; D052999:Quinazolinones; D017973:Tungsten Compounds; D002245:Carbon Dioxide; C014356:benzonitrile; C009405:tetrabutylammonium