Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1993-05-28
1994-06-21
Dentz, Bernard
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
560 80, 560 83, 560 86, 560 96, 562480, 562488, C07D30789
Patent
active
053229541
ABSTRACT:
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 R.sub.1, R.sub.2, and R.sub.4 are preferably H and R.sub.3 is preferably Cl or F.
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Bergmann, J. Appl. Chem., 3, pp., 145-146 (1953).
Olsen Gary H.
Seper Karl W.
Stults Jeffrey S.
Dentz Bernard
Fuerle Richard D.
Jones Wayne A.
Occidental Chemical Corporation
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