Method of preparing a benzofuran or benzothiophene compound
AssigneeRhodia Chimie
InventorThierry Schlama
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Abstract
The invention concerns a novel method for preparing a benzofuran or benzothiophene compound by cyclizing an aromatic compound bearing a side-chain comprising at least two carbon atoms, one of the carbon atoms being bound to the benzene cycle by an oxygen or sulphur atom, the other carbon atom is in carboxylic form and a formyl radical in ortho position relative to said chain. The inventive method is characterised in that it consists in cyclizing the latter in the presence of an efficient amount of a carbonate base in a medium comprising a carboxylic acid anhydride and optionally an organic solvent.
Claims30
A process for preparing a benzofuran or benzothiophene compound from a starting aromatic compound comprising a benzene ring, carrying firstly, a side chain comprising at least two carbon atoms, one of the carbon atoms being connected to the benzene ring via an oxygen or sulfur atom, the other carbon atom being in a carboxylic form, and secondly, a formyl group in the position ortho to said side chain, said process comprising the step of cyclising the starting aromatic compound in a medium comprising a carboxylic acid anhydride, in the presence of a base being a metallic carbonate, a metallic bicarbonate, an ammonium carbonate, or an ammonium bicarbonate.
Dependencies are inferred from the claim text.