157170-51-9Relevant academic research and scientific papers
Synthesis of 4-substituted phthalic anhydrides
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, (2008/06/13)
Disclosed is a method of making a 4-substituted phthalic anhydride. A halomaleic (including halofumaric anhydride (or the acid or ester thereof) is made by the reaction of-maleic anhydride with chlorine or bromine. The halomaleic anhydride is reacted with a conjugated diene to form a first cycloadduct having the formula STR1 The first cycloadduct is heated to eliminate HX and produce a second cycloadduct having the formula STR2 The second cyclo adduct is dehydrogenated to produce a 4substituted phthalic anhydride which has the formula STR3 where R1, R2, and R4 are preferably H and R3 is preferably Cl or F.
