Synthesis and Analgesic Activity of Some 1-Benzofurans, 1-Benzothiophenes and Indoles

Abstract

3-Unsubstituted 1-benzofurans 1e and 1f, 3-methyl-1-benzofurans 1a-1d, and 3-amino-1-benzofurans 2a-2l, as well as 3-amino-1-benzothiophenes 3a, 3b and 3-aminoindoles 4a-4f, 11a, and 11b were prepared and tested as analgesics. The 3-amino-1-benzofurans 2 were prepared from the corresponding 2-hydroxybenzonitriles 5 and phenacyl bromides 6 via intermediates 7. Similar treatment of 2-sulfanylbenzonitrile (8) provided 3-amino-1-benzothiophenes 3. Appropriately substituted 2-aminobenzonitriles 9 then provided N-substituted 3-aminoindoles 4. 1-(Ethoxycarbonyl)indoles 4e and 4f were successfully deprotected giving indoles 11a and 11b, respectively.