The synthesis of precursor of FP- (+) DTBZ

Total Synthesis of the Racemate of Laurolitsine

“…The protection of 1 with a benzyl (Bn) group furnished 2. Then, 3 was prepared via the Henry reaction and elimination reaction by adding 2, ammonium acetate, and nitromethane to an acetic acid solvent at 118 • C [19][20][21]. First, we wanted to complete the reaction by increasing the amount of nitromethane and ammonium acetate, but despite our efforts to perform many experiments, the effect was not good, the product was sticky and difficult to separate and filter, and the yield and purity were poor.…”

“…A much lower yield was obtained when LiAlH 4 was added at ambient temperature due to the generation of impurities including two compounds that only reduced the nitro group but not the double bond and only reduced the double bond but not the nitro group. Purifying the product was difficult because reduction of the double bond and nitro group was incomplete, and the polarity difference between the two impurities was very small [19][20][21]. In terms of the feeding temperature, reaction temperature, and reductant ratio, we performed a large number of experiments and ultimately determined the most suitable reaction conditions (LiAlH 4 (4 equiv.…”