75833-50-0Relevant academic research and scientific papers
Benzocyclobutenes. Part 5. Synthesis of 4-Hydroxy-, 4,5-Dihydroxy-, and 3,6-Dihydroxy-benzocyclobutene-1,2-dione (Benzologues of Semisquaric and Squaric Acid)
Abou-Teim, Omar,Jansen, Robert B.,McOmie, John F. W.,Perry, David H.
, p. 1841 - 1846 (2007/10/02)
4-Methoxy- and 4,5-dimethoxy-benzocyclobutene-1,2-dione have been made by flash vacuum pyrolysis of the anthracene adducts of the corresponding phthalazine-1,4-diones which were prepared from the appropriate methoxyphthalic anhydrides. 3,6-Dimethoxybenzocyclobutene-1,2-dione has been prepared from 2-amino-3,6-dimethoxybenzoic acid via the addition of 3,6-dimethoxybenzyne to vinylidene chloride followed by hydrolysis of the resulting 1,1-dichloro-3,6-dimethoxybenzocyclobutene, bromination, and further hydrolysis.The three methoxy-diones and 4,5-dimethoxyphthalaldehyde have been demethylated by heating them with hydrobromic acid and the pKa values of the four hydroxy-compounds have been measured.Preliminary experiments on the synthesis of 4,5-dimethoxybenzocyclobutene are recorded.
