The Development Of Practical Synthetic Routes To A Cb2 Agonist: Efficient Construction Of A Densely Substituted Purine Core

An efficient and scalable process for the preparation of a purine-based CB2 agonist was developed. The production route to the requisite purine core relies on N-acylation and sequential substitution of a 5-amino-4,6-dichloropyrimidine with two amine building blocks followed by a cyclocondensation reaction. The chemistry was successfully employed to rapidly prepare over S kg of the active pharmaceutical ingredient. To further improve efficiencies, postproduction development resulted in a rearranged synthesis which reduced the need for pressure reactors and introduced the most costly reagent in the final step.