Design, synthesis and biological evaluation of novel benzoxaborole derivatives as potent PDE4 inhibitors for topical treatment of atopic dermatitis

In this work, a series of structurally novel benzoxaborole derivatives were designed, synthesized and biologically evaluated as PDE4 inhibitors for battling atopic dermatitis (AD). Among them, the majority exhibited superior PDE4B inhibitory activities to that of the lead compound Crisaborole, an approved PDE4 inhibitor. In particular, 72, the most potent PDE4B inhibitor throughout this series, displayed 136-fold improved enzymatic activity (IC50 = 0.42 nM) as compared to Crisaborole (IC50 = 57.20 nM), along with favorable isoform specificity. In the phorbol ester (PMA)-induced mouse ear oedema model, 72 exerted remarkably greater efficacy than Crisaborole at the same dosage (P < 0.05). Moreover, the ointment of 72 exerted dramatically enhanced therapeutic potency than the ointment of Crisaborole (P < 0.05) in the calcipotriol-induced mouse AD model. In addition to the potent in vitro and in vivo activity, 72 displayed favorable safety in the repeated oral dose toxicity study and did not exhibit phototoxicity. With the above attractive biological performance, 72 is worthy of further functional investigation as a novel anti-AD therapeutic agent. (C) 2021 Elsevier Masson SAS. All rights reserved.

Automated summary

A series of structurally novel benzoxaborole derivatives were designed, synthesized, and biologically evaluated as PDE4 inhibitors for treating atopic dermatitis. Compound 72 displayed superior PDE4B inhibitory activity, with enhanced therapeutic efficacy and safety in both in vitro and in vivo studies.