However, since PEtOx is insoluble in toluene, a different solvent had to be found. After a few unsuccessful trials with acetonitrile, which gives a side reaction with LR, we settled using DCM, in which all reagents are soluble under reflux (Figure ). The first goal was to control the degree of thionation. Initial reactions were performed to aim at thionation degrees between 15% and 50%, considering that one mole of LR can ideally thionate two mole of POx repeating units. For example, a molar ratio of 125/1 of LR/P(EtOx)500 should yield 250 (or 50%) thionated repeat units.