Janus kinase (JAK) inhibitors are low molecular weight small molecules that can be used orally or topically. JAK inhibitors exert their effects through competitive inhibition of ATP binding sites found in the JH-1 domain of JAK tyrosine kinase enzymes, of which four members are known, namely JAK1, JAK2, JAK3, and TYK2. They basically contain purine-like structures such as pyrimidine, pyrrole, and pyrazolopyridine in their chemical structure. Different JAK inhibitors with different selectivity and efficacy properties were synthesized by adding cyanide, cyclobutane, trifluoroethyl, and nitrogen groups to this central compound.