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1st November 2017 @ 21:53

This reaction is the first attempt at preparing an analogue of pyrimethamine, following the method SGS 16.

Synthesis of SGS17-6-1

Crude 3-isobutoxy-2-(3-(trifluoromethyl)phenyl)pent-2-enenitrile (SGS17-2-1, ~1.5 g, 0.0050 mol, mixture of E and Z isomers) was dissolved in 40 mL DMSO.  Guanidine carbonate (1.16 g, 0.13 mol) was added to the solution and then the mixure was heated to 80 oC for 20 h.

TLC at 13 h

TLC at 13 h in DCM 

The reaction mix was poured into 20 mL of water and extracted with dichloromethane (3 x 25 mL).  The combined organic layers were left to evaporate over three days, and a small amount of red precipitate was formed, along with a red oil.

TLC of SGS17-6-1 in isobutanol against starting material (SGS17-2-1)

TLC of the (unwashed) precipitate in isobutanol showed a number of spots, including two more polar spots (R= 0.5 and 0.33 respectively) which corresponds with those seen in the synthesis of pyrimethamine here. A sample was sent to the University of Sydney for analysis. 

Reaction performed by: James Arnall, Kieran Connor, Alex Crawford, Duncan Currie, Oliver Hervir, Hugo McCahon-Boersma, Harry Thawley, Erin Sheridan