Pechmann reaction of 4-hydroxycoumarins and thiocoumarins with cyclohexanone and ethyl cyclopentanone-2-carboxylates
作者:J. R. Merchant、N. M. Koshti、K. M. Bakre
DOI:10.1002/jhet.5570180837
日期:1981.12
The Pechmann reaction of 4-hydroxycoumarins with cyclohexanone and ethyl cyclopentanone-2-carboxylates affords 1,2,3,4-tetrahydro[2]benzopyrano[4,3-c][1]benzopyran-5,12-diones and cyclopenta[3′,4′]pyrano-[3,2-c][1]benzopyran-4,11-diones. Dehydrogenation of the former yields [2]benzopyrano[4,3-c][1]benzopyran-5,12-diones. Alkaline hydrolysis of a typical compound Va affords 2-hydroxy-2′-carboxydeoxybenzoin
4-羟基香豆素与环己酮和乙基环戊酮-2-羧酸酯的Pechmann反应得到1,2,3,4-四氢[2]苯并吡喃并[4,3- c ] [1]苯并吡喃-5,12-二酮和环戊并[ 3′,4′ ]吡喃基- [3,2- c ] [1]苯并吡喃-4,11-二酮。前者的脱氢产生[2]苯并吡喃并[4,3-c] [1]苯并吡喃-5,12-二酮。典型化合物Va的碱性水解得到2-羟基-2'-羧基脱氧安息香,其在与乙酸酐一起沸腾后得到异香豆素衍生物。