Ethyl 4,5-dihydro-4-oxothieno<3,2-c>pyridine-6-carboxylate
4-ethoxy-thieno[3,2-c]pyridine-6-carboxylic acid ethyl ester
2-azido-3-(3-formyl-thiophen-2-yl)-acrylic acid ethyl ester
2-azido-3-(3-diethoxymethyl-thiophen-2-yl)-acrylic acid ethyl ester