Phenanthrene 3:4-diacetoxy

Sinomeninone [xxv] (see Chap. XXVI) on heating with acetic anhydride and sodium acetate is converted to 3-methoxy-4 6-diacetoxy-phenanthrene (20 per cent.) and triacetyk sothebenine (10 per cent.) 1-bromosinomeninone under the same conditions gives 20 per cent. 1-bromotriacetyKsotbebenine. Catalytic reduction of these two bases yields triacetyl-9 10-dihydroisothebenine [15], identical with the triacetyl wot hebeni no prepared by Schopf, Pfeiffer, and Hirsch [27] from (—) 1-bromosinomeninone (see Chap. XXVI). 

Diacetoxy-3-methoxyphenanthrene and triacetylisothebenine are obtained by the acetolysis of sinomenine hydrate and the 1-bromo-derivatives of these can be prepared in the same way from 1-bromosinomeninone. Catalytic reduction of both triacetylisothebenine and its 1-bromo-derivative affords triacetyl-9 10-dihydroisothebenine [55], believed by Schopf, Pfeiffer, and Hirsch [64] to be triacetylisothebenine when the same sequence of reactions was carried out on (—)-l-bromo-sinomeninone. /sothebenine is probably 4 6-dihydroxy-3-methoxy-5-(/3-methylaminoethyl)-phenanthrene [lxxxh], or the 4 7-dihydroxy-isomer [64], On heating with sodium hydroxide and methyl alcohol at 80° C., 1-bromotriacetyKsothebenine yields a compound C2oH2004NBr in 7 per cent, yield this is probably 1 -bromo-N-acetylisothebenine [55] (see also Chap. XXV). 

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