The synthesis of N,N-disubstituted 3-aminomethylene-5-hydroxy-2,2-dimethyl-7-pentyl-4-chromanones (III) and their reaction with dichloroketene are described. The resulting cycloadducts (IV) gave, by dehydrochlorination, the N,N-disubstituted 4-amino-3-chloro-10-hydroxy-5,5-dimethyl-8-pentyl-2H,5H-pyrano[3,2-c] [1]benzopyran-2-ones (V), which are structurally related to tetrahydrocannabinols. Only the compound (V a) displayed a very weak stimulant activity on the CNS.
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