Method for preparing aromatic compounds
AssigneeRohm and Haas Company
InventorsHeather Lynnette Rayle, Randall Wayne Stephens
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Abstract
A method for synthesizing aromatic compounds by selectively dehalogenating aromatic starting materials is provided. Compounds may be prepared which are substituted with fluoro, chloro or bromo. The method may be used to remove halogen atoms from sites at which halogenation is not desired, and to form substantially pure halogenated compounds from mixtures of starting materials. The method uses a copper containing dehalogenation agent and an acid with the dehalogenation being controlled by a substituent such as a carboxylic acid, amide, ester, aldehyde, ketone or cyano on the aromatic ring.
Claims23
A method for preparing an aryl or a heteroaryl compound by selectively removing halogen atoms from a halogenated aryl or heteroaryl compound through heating a reaction mixture comprising
- (i) at least one aryl or heteroaryl compound possessing a Z directing group and one or two halo groups independently selected from chloro, bromo and iodo which are ortho to said Z group, or a further substituted aryl or heteroaryl compound possessing a Z directing group and one or two halo groups independently selected from chloro, bromo and iodo which are ortho to said Z group,
- (ii) from about 0.01 to about 5.0 molar equivalents, per equivalent of halo group to be removed, of a copper containing dehalogenation agent, and
- (iii) at least about 1.0 molar equivalent, per equivalent of halo group to be removed, of one or more acids selected from the group consisting of aliphatic (C.sub.1 -C.sub.10)carboxylic acids, aliphatic (C.sub.2 -C.sub.10)dicarboxylic acids, aryl carboxylic acids, aryl dicarboxylic acids, aqueous inorganic acids, sulfonic acids and mixtures thereof;
- wherein
- the Z directing group is CO.sub.2 R.sup.10, CONR.sup.11 R.sup.12, COR.sup.13 or cyano,
- R.sup.10, R.sup.11 and R.sup.12 are each independently a hydrogen atom, (C.sub.1 -C.sub.6)alkyl, aryl or substituted aryl, and
- R.sup.13 is a hydrogen atom, (C.sub.1 -C.sub.6)alkyl, substituted (C.sub.1 -C.sub.6)alkyl, aryl or substituted aryl.
Dependencies are inferred from the claim text.