How is ethyl 4-(cyclopentylamino)-2-methylsulfanyl-pyrimidine-5-carboxylate (CAS: 211245-62-4) typically synthesized?

Ethyl 4-(cyclopentylamino)-2-methylsulfanyl-pyrimidine-5-carboxylate is typically synthesized through a multi-step process involving the reaction of an appropriate amino compound with a pyrimidine derivative, followed by the introduction of the ethyl group via an esterification step. Commonly used catalysts include acid catalysts, and the reaction is highly selective, resulting in good yields.