The synthesis of two carbonyl 4, 7-dihydrothieno (2, 3) pyridines 1a and 1b is described. These derivatives are potential new NADH models. A NHR study of the complexation of magnesium ions by these compounds has been performed. The behaviour of the thieno [2, 3- b) derivative is different of that of the thieno [3, 2-b] derivative: in the former the sulfur atom plays an important role in the complexation. The biomimetic reduction of p. ...