How is 2-Methyl-2-propanyl 4-chloro-7,8-dihydropyrido[4,3-d]pyrimidine-6(5H)-carboxylate (CAS: 1056934-87-2) typically synthesized?

This compound can be synthesized via a multi-step process that starts with the protection of the primary amine, followed by a ring closure to form the pyridopyrimidine core, and then deprotection to yield the final carboxylate. Commonly used catalysts include benzotriazol-1-yloxy-tripyrrolidine-phosphonium hexafluorophosphate (BOP) and 1-hydroxybenzotriazole (HOBt). The reaction typically yields a mixture that requires purification.