Isopropanol was the next solvent attempted at 85 °C, which showed improved yields of 87% after 24 h with minimal impurity formation. To catalyse the reaction, with the aim of reducing the reaction time, the reaction was repeated in isopropanol in the presence of p-toluenesulfonic acid (p-TSA) as catalyst (Entry 6). However, TLC analysis showed formation of more impurities than was observed in the earlier attempt (Entry 4) and the Mannich base (14) was obtained in reduced yields of 61% (versus 87%). It was clear at this point that the use of any acid promoted the formation of more impurities. The next attempt saw the reaction performed in toluene at 85 °C which afforded 14 in an excellent yield of 95% within 15 h. Moreover, to the best of our knowledge, a C-C bond formation Mannich reaction in toluene has not been reported in the literature previously. Due to toluene's relative affordability and its ability to be recycled and reused, this contributes to cost cutting and ultimately renders our process competitively cheaper.