6,9-dihydroxy-2-methyl-2-(4-methyl-3-pentenyl)-2H-naphtho<2,3-b>pyran-5,10-dione 、
柠檬醛 在
盐酸甲胺 作用下,
以
乙醇 为溶剂,
生成 5,12-dihydroxy-2,8-dimethyl-7-(3-methyl-2-butenyl)-2-(4-methyl-3-pentenyl)-2H-anthra<2,3-b>pyran-6,11-dione 、 5,12-dihydroxy-2-methyl-2,8-bis(4-methyl-3-pentenyl)-2H-anthra<2,3-b>pyran-6,11-dione