4-{7H-pyrrolo[2,3-d]pyrimidin-4-yl}-1H-pyrazole is used in the preparation of deazapurines such as Ruxolitinib(R702000) which is a selective Janus tyrosine kinase (JAK1 and JAK2) inhibitor used in the treatment of myeloproliferative neoplasms and psoriasis. Potent JAK2 inhibitor.