Synthesis of asymmetric tetracarboxylic acids and...

Details Synthesis of asymmetric tetracarboxylic acids and... Synthesis of asymmetric tetracarboxylic acids and...

2008-09-16

2008-09-16

Puttlitz, Karl J (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Carboxylic acids and salts thereof

C562S491000, C562S480000, C562S887000

Reexamination Certificate

active

11378553

ABSTRACT:
This invention relates to processes for preparing asymmetrical biphenyl tetracarboxylic acids and the corresponding asymmetrical dianhydrides, namely 2,3,3′,4′-biphenyl dianhydride (a-BPDA), 2,3,3′,4′-benzophenone dianhydride (a-BTDA) and 3,4′-methylenediphthalic anhydride (-MDPA). By cross-coupling reactions of reactive metal substituted o-xylenes or by cross-coupling o-xylene derivatives in the presence of catalysts, this invention specifically produces asymmetrical biphenyl intermediates that are subsequently oxidized or hydrolyzed and oxidized to provide asymmetric biphenyl tetracarboxylic acids in comparatively high yields. These asymmetrical biphenyl tetracarboxylic acids are subsequently converted to the corresponding asymmetrical dianhydrides without contamination by symmetrical biphenyl dianhydrides.

REFERENCES:
patent: 3940426 (1976-02-01), Itatani
patent: 4294976 (1981-10-01), Itatani
patent: 4958002 (1990-09-01), Imatani
patent: 5258530 (1993-11-01), Katsuro
patent: 2003/0088120 (2003-05-01), Yamamoto
patent: 343560 (1989-11-01), None
Polyhedron, 10(17), 2037-44; 1991.

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