Synthesis Of 4a Lab Report

Thus a solution α-naphthol 1a, 4-methylbenzaldehyde 2a and tert-butyl isocyanide 3a in EtOH was magnetically stirred at 45 C for 12 hours under an oxygen atmosphere with an equimolar ratio of the three reactants. TLC monitoring of the reaction mixture exhibited formation of a new product, which was purified (Table 1, entry 1). Identification of its structure by NMR spectroscopy revealed that it was 2-(4-methylbenzoyl)-1-naphthyl N-(tert-butyl)carbamate (4a). Next, in order to improve the yield of 4a, the effects of different solvents, reaction temperatures and times together with the molar ratio of the reactants were examined in this model reaction, for which the reaction conditions would be optimized. When this reaction was performed in refluxing EtOH, 7a was obtained
Subsequently, the reaction was carried out under solvent-free conditions at different temperatures and times. Thus 4a obtained in 65% yield at 150 °C after 8 h. It could be seen that the best result was attained at 150 C after 3 hours which led to an optimized yield of 62% of 3a (Entry 8). Next the reaction was performed by different ratios of the three reactants. The best result was obtained when the reaction was performed with a 1:1.1:1.1 molar ratios of 1a, 2a and 3a NH4OAc, respectively. It could be seen that the best result was again attained with a 1:2:3 molar ratio of the three reactants, a reaction temperature of 150 °C and a reaction time of 8 h, in which 3a was obtained in 97% yield (Entry 19, with 1a as the limiting reagent). We explored the effect of reaction’s atmosphere and we changed it from oxygen to air and nitrogen, which showed that under air atmosphere, the yield decreased to 6%, and no producd was detected under nitrogen atmosphere (Entries 9 and 20). Increasing the temperature beyond 150 °C led to a decrease in yield due to the formation of some side products (Entry