Not only “from scratch”, he even did it from widely available household products.
I think he said in the last video that it would have been cheaper and faster if he had bought some of the precursor chemicals directly instead of having to make them first.
Well, from my limited 100-level-chemistry-plus-youtube education, he could have just bought the immediate precursors directly for pyrimethamine itself, i.e. possibly even 2-(p-chlorophenyl)-3-oxopentanenitrile, guanadinium chloride, and Trimethyl Orthoformate, which would make it a 3-step synthesis instead of a 17-step synthesis, so yeah, pretty easy. At the very least he could cut out ~2/3rds of those steps for a 7-step or 6-step synthesis.
So cheaper by easily an order of magnitude, possibly ~$100 a batch or less. Of course, if you want FDA grade instead of technical grade your prices for everything skyrocket and your workup has to improve a bunch.
I think he said in the last video that it would have been cheaper and faster if he had bought some of the precursor chemicals directly instead of having to make them first.