In an oven dried flask, under nitrogen atmosphere, was charged sodium azide (1.4 eq, 84 mg). Et2AlCl (1.4 eq, 1.08 ml of 1.8 M solution in toluene) was added through syringe. The mixture was stirred at room temperature for 4 hours. 4-phenoxythieno[3,2-c]quinoline-7-carbonitrile (1.0 eq, 20 mg) was charged in a vial. Et2AlN3 solution (0.15 ml) was added and the resulting mixture stirred at 80° C. for 5 days. The mixture was treated by a solution of NaOH and some sodium nitrite was added (pH=13-14). The pH was adjusted to 1.5 with HCl 6N. The material was extracted with ethyl acetate. The material was extracted from the organic phase using a saturated aqueous solution of K2CO3. The pH was adjusted to 2.5 with HCl 6N and the material was extracted with ethyl acetate. The solvent were evaporated to afford 4-phenoxy-7-(1H-tetrazol-5-yl)thieno[3,2-c]quinoline. LCMS (ES)>95% pure, m/z 303 [M+1]+.
