Synthesis of bioactive heterocycles: One pot regioselective synthesis of pyrano[3,2-f]benzo[b]thiophene derivatives
作者:Krishna C Majumdar、Paritosh Biswas
DOI:10.1016/s0040-4020(98)01124-7
日期:1999.1
Regioselective synthesis of hitherto unreported pyrano[3,2-f]benzo[b]thiophene derivatives (8a-f) in 90–95% yields are reported by the application of a less studied rearrangement of 6-(4-aryloxybut-2-ynylthio)[1]benzopyran-2-ones (5a-f) via oxidation with m-chloroperoxybenzoic acid followed by thermal rearrangement and treatment with methanol. Substrates 5a-f are prepared by the reaction of 6-mercaptocoumarin
据报道,迄今未报道的吡喃并[3,2- f ]苯并[ b ]噻吩衍生物(8a-f)的区域选择性合成产率为90-95%,这是通过对6-(4-芳氧基丁-2- ynylthio)[1]苯并吡喃-2-酮(5A-F )通过与氧化米氯过氧苯甲酸,接着热重排并用甲醇处理。通过使6-巯基香豆素(不稳定的)与1-芳氧基-4-氯丁-2-炔(4)在回流的丙酮中,在无水碳酸钾和碘化钠的存在下反应来制备底物5a-f。6-巯基香豆素(3)依次通过重氮化的6-氨基香豆素(1)与乙基黄原酸钾反应然后分解而获得的二硫化物(2)的锌酸还原而制备。在丙酮中回流时,吡喃并[3,2- f ]-苯并[ b ]噻吩衍生物(8a-f)容易转化为1-乙酰基吡喃并[3,2- f ]苯并[ b ]噻吩-7-一(12)。在催化量浓溶液中存在酸。硫酸4小时。