Dear community,

I'm having a lot of trouble trying to obtain 2,4-diaminopyrimidines to my PhD project. The best way I could find so far to introduce the 2 amino groups is through double SNAr followed by double PMB deprotection. I first tried TFA, r.t. or heating at 100°C, but in the end I could get only one deprotection gone. Then, I chanced to hydrogenation, and I had to use PdOH2, acetic acid as solvent and heat it up to 80°C. It worked for a series of compounds, but this conditions is not working for other compounds.

What is your recommendation? Have you guys tried to perform a double PMB deprotection? What is the best reaction condition?