How is 5,6,7,8-Tetrahydropyrido[4,3-d]pyrimidine (CAS: 192869-50-4) typically synthesized?

5,6,7,8-Tetrahydropyrido[4,3-d]pyrimidine can be synthesized via a multi-step process including condensation reactions and ring formation. Common synthetic routes involve the reaction of 2,4,6-triiodopyrimidine with a secondary amine in the presence of a base like potassium carbonate. The yield is typically around 70-80%, and the reaction usually requires heating and use of anhydrous conditions to achieve high purity.