Not sure how flexible this one is, but it looks cheap enough for a small department to make their own sildenafil: https://science.sciencemag.org/content/363/642

Not sure how flexible this one is, but it looks cheap enough for a small department to make their own sildenafil: https://science.sciencemag.org/content/363/6423/eaav2211.full https://science.sciencemag.org/content/363/6423/eaav2211.ful... The yields are quite bad though AFAICT.