RODRIGO SOUZA
Biocatalysis and Organic Synthesis Group, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazils

Following the idea to discuss the synthesis of recently approved APIs, in this issue we will present synthetic strategies towards the synthesis of abrocitinib, a Janus kinase inhibitor (JAK1) used for the treatment of adults living with refractory, moderate-to-severe atopic dermatitis (AD), developed by Pfizer. Abrocitinib sold under the brand name Cibinqo was approved on 14th of January 2022 (already approved in UK, Japan and Europe in 2021) with an oral, once-daily dose, after five large scale clinical trials (1, 2).

Protein kinases are families of enzymes that catalyze the phosphorylation of specific residues in proteins, where inappropriate tyrosine kinase activity (JAK1, JAK2, JAK3, and Tyk2) can lead to a variety of biological cellular responses related to already known autoimmune and hematological disorders (3).

Synthetic strategies towards abrocitinib are focused on the construction of the diaminecyclobutane ring 3, starting in most ... ...