Cyclic diacyl thioureas enhance activity of corrector Lumacaftor on F508del‐CFTR

Cystic fibrosis is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. In the search of novel series of CFTR modulators, a library of mono and diacyl thioureas were prepared by sequential synthesis. When tested alone, the obtained compounds 5 and 6 poorly affected F508del‐CFTR conductance but, in combination with Lumacaftor, selected derivatives showed the ability to increase the activity of the approved modulator. Analogue 6i displayed the most marked enhancing effect and acylthioureas 6d and 6f were also able to improve efficacy of Lumacaftor. All compounds proved to be non‐cytotoxic against different cancer cell lines. Good pharmacokinetic properties were predicted for derivatives 5 and 6, thus supporting the value of these compounds for the development of novel modulators potentially useful for cystic fibrosis.