2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 8-Methoxypsoralen

Participants

Reaction Steps

A reaction mixture of 218 g of 2,3-dihydroxanthotoxin of Part E, 281 g of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, and 3 liters of toluene was stirred and heated at reflux for 20 hours. The mixture was cooled and poured into 10 liters of 10 percent sodium hydroxide solution containing 5 percent sodium dithionite. The solution was then extracted twice with about 2 liters of chloroform. The combined chloroform extracts were washed with water and dried over sodium sulphate and concentrated to dryness. There was obtained 150 g (70 percent yield), of crude 8-methoxypsoralen which on crystallization from benzene was obtained as white crystals melting at 138°-140° C.

Provenance & Evidence