(一) Acid-Promoted Regioselective Synthesis of 2-Aminoquinazolin-4-ones(二) Synthetic Studies of 2-Aminoimidazoles

• Main Authors: Yeh, Wen-Hsiung, 葉文雄
• Other Authors: Chien, Tun-Cheng
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/65924138476205097712

碩士 === 國立臺灣師範大學 === 化學系 === 103 === In the first part of the thesis, we developed a simple and mild method to synthesize 3-aryl-2-amino- and 2-arylamino-quinazolin-4-ones from methyl 2-aminobenzoates with various aryl cyanamides under the catalysis of acids. We used 4-toluenesulfonic acid monohydrate as the promoting acid to give 3-substituted 2-aminoquinazolin-4-ones with good regioselectivity. Besides, the 2-arylamino-substituted quinazolin-4-ones can be obtained from 3-substituted 2-aminoquinazolin-4-ones by Dimroth rearrangement, which was proceeded under strong basic condition. If the aryl substitutents on 2-aminoquinazolin-4-ones possessed ortho-bromo substitutent, the intramolecular Copper(I)-catalyzed C-N bond formation can afford the tetracyclic benzimidazo[2,1-b]quinazolin-12-one derivatives. The tetracyclic heterocyclic skeleton has attracted much attention for its application as potential immunosuppressors and anti-tumor agents. The second part is the synthesis of 2-aminoimidazoles from cinnamonitriles. The cinnamonitriles were reacted with hydroxylamine to form the corresponding carboxamidoximes, which then underwent Tiemann rearrangement reaction to afford corresponding of N-phenylethylene-N-arylsulfonylcyanamides. The N-phenylethylene-N-arylsulfonylcyanamides were reacted with hydroxylamine again to form the corresponding N-phenylethylene-N-arylsulfonyl-N’-hydroxyguanidines. Sulfonylation of the above N’-hydroxyguanidines afforded 2-aminoimidazole derivatives via intramolecular electrophilic addition.