3-Hydroxythieno [3, 2-b] pyrrole-2-carboxaldehyde (111) reacts with n-butanethiol and N- methylaniline to give the methylene derivatives IVb and IVc, respectively. In the Mannioh reaction with formaldehyde and secondary amines, 2-benzylidene-2H, 3H-thieno [3, 2-b] pyrrol-3-one (IYa) and IVb are attacked in the 6-position. One of the Mannich bases, Va, reacts with acetic anhydride to form 4-acetyl-6-acetoxymethyl-2-benzylidene-2H,-3H- ...