How is 4-Amino-7H-pyrrolo[2,3-d]pyrimidine-2-thiol (CAS: 98198-24-4) typically synthesized?

4-Amino-7H-pyrrolo[2,3-d]pyrimidine-2-thiol is typically synthesized via the condensation of 2-thiouracil and an amino derivative. The reaction usually involves the use of a mild base such as sodium bicarbonate as a catalyst. The yield is generally around 70-80%, and the product can be purified by recrystallization or column chromatography.