Susumu Mihashi

Phenolic compounds from the rhizomes of Alpinia speciosa

From the rhizomes of Alpinia speciosa, a new dihydrochalcone, dihydroflavokawin B, has been isolated together with six known phenolic compounds. The chemotaxonomic significance of these findings is discussed briefly.

Furoquinolines. XXI. Synthesis and Alkoxyl Interchange of 4-Ethoxy furo [2, 3-b] quinoline and its 2, 3-Dihydro Analogs.

The ethoxyl analogs of 2, 3-dihydrodictamnine (III) and 2, 3-dihydroevolitrine (IV) were prepared from the corresponding 4-chloro-3-(2-chloroethyl) carbostyrils (I and II) by heating with ethanolic alkali. Dehydrogenation of (III) gave the ethoxyl analog of dictamnine (V), whose alkoxyl interchange with methanolic potassium hydroxide furnished dictamnine (VI). 2, 3-Dihydrodictamnine (VII), 2, 3-dihydroevolitrine (VIII), and 2, 3-dihydroskimmianine (IX) did not undergo conversion, except (VII), to the corresponding ethoxyl analogs with ethanolic alkali. An attempted conversion of (III) and (IV) to the respective (VII) and (VIII) failed.