The first synthesis of 4,10-dihydro-3-hydroxy-3-methyl-1H,3H-pyrano[4,3-b][1]benzopyran-10-one, the basicskeleton in fulvicacid, was achieved by sequential cyclization, which involved hydrogenation of the boron complex of the dione (5) obtained by regioselective cyclization of the acetal (4) with HCl in tetrahydrofuran.
首次合成了黄腐酸的基本骨架4,10-二氢-3-羟基-3-甲基-1 H,3 H-吡喃并[4,3- b ] [1]苯并吡喃-10-酮通过顺序环化,其中涉及通过在四氢呋喃中用HCl对乙缩醛(4)进行区域选择性环化而获得的二酮(5)的硼配合物的氢化。
YAMAUCHI, MASASHIGE;KATAYAMA, SADAMU;NAKASHITA, YOSHIHIKO;WATANABE, TOSHI+, J. CHEM. SOC. PERKIN TRANS., 1985, N 1, 183-186