Friday ½/2018

Reduction of 2 to form 3 (AS05)

After allowing the precipitate to settle, I wasn’t confident that the precipitate wasn’t just some residual \(\ce{MgSO4}\), So I reduced down the mixture with the rotary evaporator and redissolved the residue in minimal DCM, to ensure that the desired product 3 was in solution. I then filtered the solution (which was turbid at this point) through a pipette with some cotton wool and celite in it (fig:AS05filterpipette), which gave me a crystal clear, yellow solution

After drying this again and taking an NMR, the results showed very little, because the solvent peaks were just too great ([fig:AS05NMRsolventpeaks] Bottom).

Filtering the turbid solution through celite

NMR spectra of dried residue with too high solvent peaks (Bottom) and of the whole sample fully dried (Top) I wasn’t happy with the first filtering anyway, so I set up a new pipette, re-filtered the solution and decided to dry the solution over a longer period of time (while I went to lunch) to try and get the residue as dry as possible. The second NMR didn’t show much change, despite the solution being significantly more concentrated (

fig:AS05NMRsolventpeaks Top), so I have passed the information to my supervisor for some more guidance.