Department of 4.6-Dibromoresorcinol dimethyl ether has been converted into 4.6-dihydroxyisophthalaldehyde (1 1 ) by lithiumbromine interchange, formylation, and demethylation. Similarly the 5-methyl and 5-methoxy-derivatives were prepared, all in good overall yields. Three dioxa-anthracenediones have been prepared from the isophthalaldehydes. Low-temperature lithium-bromine interchange, formylation, and selective demethylation provided a route to 5-brorno-3,4-dimethoxysalicylaldehyde (1 4), which has potential as an intermediate for the synthesis of oxygen heterocycles. Chemistry, Kalamazoo College, Kalamazoo, Michigan 49001, U.S.A. WE have prepared 4,6-dihydroxyisophthalaldehyde (1 1)and its 5-methyl and 5-methoxy-derivatives, compounds which have potential as synthetic intermediates.* Treatment of 1,5-dibrom0-2,4-dimethoxybenzene (1) with an excess of butyl-lithium and then N-methylformanilide gave 4,6-dimethoxyisophthalaldehyde (4) (72%) and 2,4-dimethoxybenzaldehyde (1 1 yo). Demethylation of (4) with aluminium bromide in nitrobenzene was accompanied by nuclear bromination to give (9) (76%). Aluminium chloride in 1,2-dichloroethane gave partial demethylation to afford (10) (5y0), but in nitrobenzene dihydroxyisophthalaldehyde (1 1) (87%) was formed.To examine the scope of this reaction the &methyl and 5-methoxy-derivatives of (1 1) were prepared.* The use of (11) in a study of cobalt(II1) chelates has been reported,l but its source could not be ascertained (M. Colvin, personal communication).Bromination of 2,6-dimethoxytoluene gave (2) (78%) which was treated with an excess of butyl-lithium followed by NN-dimethylformamide to give (5) (74%). Demethylation of this with aluminium chloride in nitrobenzene proceeded smoothly to give (12) (89%).The trimethoxyisophthalaldehyde (6) was prepared similarly (55%) from 4,6-dibromopyrogallol trimethyl ether 3 (3) ; on demethylation it gave 4,6-dihydroxy-5-methoxyisophthalaldehyde (13) (67%).The use of these intermediates in the synthesis of symmetrical oxygen heterocycles was exemplified by condensing 4,6-dihydroxyisophthalaldehyde (1 1) with acetic Lanhydride under Perkin conditions to give the

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The first parent benzodifuran (XVI) and three di‐ and trimethylated derivatives have been synthesized and screened for erythemal activity (negative response). Two benzodifurans were prepared from resorcinol and 2‐methylresorcinol by acetylation, Fries rearrangement, alkylation of the resulting 4,6‐diacetylresorcinols with ethyl bromoacetate, saponification, and then cyclization of the (4,6‐diacetyl‐1,3‐phenylenedioxy)diacetic acids. Another was prepared from the Claisen rearrangement product of 1,3‐bis(allyloxy)‐2‐methylbenzene by acetylation, bromina‐tion, and cyclization. Ozonolysis of the Claisen rearrangement product gave additional support to the formulation of o‐hydroxyphenylaeetaldehydes as cyclic hemiacetals. The parent benzodifuran was synthesized from 5‐formyI‐6‐hydroxybenzofuran, which was prepared in two steps from 5‐bromo‐6‐methoxybenzofuran. Alkylation of the former with ethyl bromoacetate, saponification, and cyclization furnished benzo[1,2‐b.5,4‐b ]difuran. The ultraviolet and nuclear magnetic resonance spectra of the four benzodifurans are compared.

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Coumarone intermediate: o‐Formylphenoxyacetic acid . product: benzofuran byproduct: coumarilic acid