Phenylhydrazones as Correctors of a Mutant Cystic Fibrosis Transmembrane Conductance Regulator.

The phenylhydrazone RDR-1 is endowed with moderate activity as F508del-CFTR corrector; nevertheless, its simple structure enables stimulating developments in this class of correctors. Therefore, we synthesized a number of phenylhydrazones 3 by reacting phenylhydrazine derivatives 1 with furfural derivatives 2. By the same reaction, also the pyridine derivatives 4, the thiophene derivatives 5, and the hydrazides 6 and 7 were prepared. All compounds were tested as F508del-CFTR correctors in the cystic fibrosis (CF) bronchial epithelial cell line CFBE41o-, using corr-4a and VX-809 as controls. Some of the tested compounds emerged as interesting F508del-CFTR correctors at 20 μM (3c) and 2 μM (5d). 3c and 5d administered together with VX-809 produced a satisfactory additivity of action. When the structure of 5d was overlapped with RDR-1 and five other established correctors, a shared central design was clearly visible. This fact may be of interest in the search for new F508del-CFTR correctors.