Condensed thiophen ring systems. Part XVII. A new synthesis of 10H-indeno[1,2-b][1]benzothiophen

Abstract

2-Phenylbenzo[b]thiophen-3-carbaldehyde p-tolylsulphonylhydrazone (7) reacted with sodium methoxide in hot bis-(2-methoxyethyl) ether to give the title compound (2)(30%), together with NN′-bis-(2-phenylbenzo[b]thiophen-3-ylidene)hydrazine (15)(<5%), 2-phenyl-3-p-tolylsulphonylmethylbenzo[b]thiophen (8)(10·5%), and tar. By contrast, 3-phenylbenzo[b]thiophen-2-carbaldehyde p-tolylsulphonylhydrazone (13) gave a complex mixture of products which contained 2-hydroxymethyl-3-phenylbenzo[b]thiophen (14)(18%).