The synthesis of 6,7'-dimethoxychromeno(3', 4'-3,2) coumarone (3,4-dehydrohomopterocarpin) (11; R' = H, R = R" = OMe) and of (f)-dihydrohomopterocarpin (VI) are recorded. Dehydrogenation of homopterocarpin yields either 2,3-dehydrohomopterocarpin (IX) or 3-fi-anisoyl-7-methoxycoumarin (VIII) , according to conditions. Pterocarpin similarly gives 7-methoxy-3-(3 , 4-methylenedioxyphenyl) coumarin.DURING investigations directed towards a synthesis of homopterocarpin (I) the chromeno-(3',4'-3,2)coumarone system (11) has been synthesised.Reduction of di-0-methylcoumestrol (111; R' = H, R = R" = OMe) 2 9 3 with lithium aluminium hydride gave 2-(2-hydroxy-4-methoxyphenyl)-3-hydroxymethyl-6-methoxy-heated. This structure is in agreement with the light absorption (see Experimental section) and the nuclear magnetic resonance spectrum, which shows six aromatic protons, two methoxyl groups (singlets at T 6.33 and 6.34) and a doublet at T 5.02 ( J 1 c./sec.

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Aus o‐Hydroxyacetophenon wird mit Piperonal das Chalcon (I) erhalten, das in Gegenwart von H2O2 und Alkali zu (IIa) cyclisiert und oxidiert wird.

Acylierung des Piperidinenamins (I) mit 2,4‐Diacetoxybenzoylchlorid (II) und nachfolgende Cyclisierung in wäßrigem Pyridin/Piperidin liefert III‐Baptigenin (III).

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