Agera-turn houstonianum Mill, with the synonym Ageratum mexicanum Sims belongs to the family Composite. From the essential oil of this plant a crystalline substance C13H1603 (i) with m.p. 47.5 was obtained. The name ageratochromene was proposed for it. The oxidations which were carried out to degrade (I) to a substance with a smaller number of C-atoms in order to determine its structure, are illustrated in the scheme on page 11. Catalytic hydrogenation of (I) gave a dihydrocompound (II). From the infra-red and ultraviolet spectra of (I) and (II) it could be concluded that the double bond was conjugated with a benzene nucleus. Based on the knowledge of the structure of (I) obtained during the experimental work, 6:7-dimethoxy-2:2-dimethyl-chroman (X) was synthesized, and (X) was identical with (II) according to melting point, mixed melting point and infra-red spectrum. Ageratochromene is therefore 6:7-dimethoxy-2:2-dimethylchromene.
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