Derivate des Benzo[1.3]dioxols, 47 . Darstellung und Reaktionen des 4.8-Dimethoxy-bis[1.3]dioxolo[4.5]benzo- [1.2-d; 1′ .2′ -f] [1.3]dioxepins / Derivatives of 1,3-Benzodioxoles, 47 . Preparation and Reactions of 4,8-Dimethoxy-bis[1,3]dioxolo[4,5]benzo- [1,2-d; 1',2'-f][1,3]dioxepine
Zeitschrift für Naturforschung. B, A journal of chemical sciences
In 1957 some dibenzo[d,f][1,3]dioxepines were isolated from Cercospora kikuchii. We describe the preparation of 4,8-dimethoxy-bis[1,3]dioxolo[4,5]benzo[1,2-d; 1',2'-f][1,3]-dioxepine (3). It shows a high SE-reactivity. Bromination yields the monobromo-and dibromocompounds 3 a and 3 b. Treatment of 3 with copper(II) nitrate leads to the dinitrocompound 3c. With the same reagent 3a gives 3d. Reduction of 3d with hydrogen and Palladium as catalyst yields the mono-amine 3e under bromine loss. Under
... bromine loss. Under the same reduction conditions in acetic anhydride 3d and 3c yields 3f respectively 3g. The carboxylic acid 3i and the aldehyd 3h are prepared by bromine-lithium exchange from 3 a. In the same manner the dibromocompound 3 b is a suitable starting material to obtain the dicarboxylic acid 3k and the dialdehyd 3j. 3j undergoes easily a thiazolium catalysed oin-condensation, yielding the phenanthrenequinone 3l. The cyclic anhydride 3 m can be prepared by heating 3 k in acetic anhydride.