An efficient ionic liquid mediated synthesis of substituted 5H[1,3]-thiazolo[2,3-b]quinazoline-3,5-(2H)-dione and 5H-thiazolo[2,3-b]quinazolin-5-one
作者:Ashok K. Yadav、Pankaj Dhakad、Gopi Ram Sharma
DOI:10.1016/j.tetlet.2013.08.090
日期:2013.11
A new, environmentally benign two-step synthesis of 5H[1,3]-thiazolo[2,3-b]quinazoline-3,5-(2H)-dione and 5H-thiazolo[2,3-b]quinazolin-5-one derivatives has been accomplished stepwise. The substituted 2-aminobenzoic acid upon condensation with thiourea in 1-butyl-3-methylimidazolium bromide at moderate temperature under nitrogen atmosphere yielded 2-thioxo-1H-4-quinazolinones. The resulting intermediate
5 H [1,3]-噻唑并[2,3- b ]喹唑啉-3,5-(2 H)-二酮和5 H-噻唑并[2,3- b ]的新的环境友好的两步合成方法喹唑啉-5-酮衍生物已逐步完成。在氮气氛下,于中等温度下,在1-丁基-3-甲基咪唑鎓溴化物中,与硫脲缩合后,取代的2-氨基苯甲酸产生2-硫代-1 H -4-喹唑啉酮。当与2-氯乙酸/ 2-氯丙醛反应时,所得的中间体2-thioxo-1 H -4-喹唑啉酮进行环化,以优异的收率得到所需产物。