Process for preparing 3-(4-aminoethoxy-benzoyl) benzo B!-thiophenes
AssigneeEli Lilly and Company
InventorCharles A. Alt
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Abstract
The invention provides a process for preparing 6-alkoxy-3-(4-alkoxyphenyl)benzo B!thiophenes in good yield on a manufacturing scale without generating a thick, potentially yield-reducing, paste. The invention also provides methods for converting a-(-alkoxyphenylthio)-4-alkoxyacetophenones into 6-hydroxy-2-(4-hydroxyphenyl)-3- 4-(2-aminoethoxy)benzoyl!benzo B!thiophen es via acylation of a dialkoxy benzo B!thiophene. Each of these preparations relies on an intramolecular cyclization of a dialkoxy acetophenone derivative to yield a benzo B!thiophene without generating a thick paste that lowers overall yields on a manufacturing scale.
Claims5
A process for preparing a benzo B!thiophene of the formula ##STR8## wherein the R groups are the same or different and represent C.sub.1 -C.sub.6 alkyl, the process comprising cyclizing a dialkoxy compound of the formula ##STR9## in the presence of polyphosphoric acid and phosphoric acid.
Dependencies are inferred from the claim text.