合成路线1

Condensation of methyl 3,5-dihydroxybenzoate (I) with 3-chloro-3-methyl-1-butyne (II) in the presence of CuI, followed by thermal cyclization at 75 C, gives rise to a mixture of two regioisomeric chromenes (III) and (IV). After chromatographic separation, the desired isomer (III) is reduced with LiAlH4 to provide alcohol (V). Copper-catalyzed coupling of the phenolic chromene (V) with sodium 2-iodobenzoate (VI) leads to the diaryl ether (VII), which is further cyclized to the pyranoxanthenone (VIII) in the presence of trifluoroacetic anhydride. After basic hydrolysis of the trifluoroacetate ester (VIII), the resultant alcohol (IX) is converted to mesylate (X) by treatment with methanesulfonyl chloride and triethylamine. Finally, displacement of the mesylate group of (X) with N,N-diethyl ethylenediamine (XI) furnishes the title compound.