Everywhere on the internet I see that the two $\mathrm pK_\mathrm a$'s of ketoconazole are 6.4 and 2.3, but I don't think that is correct.
The $\mathrm pK_\mathrm a$ of imidazole is around 6.4 . But ketoconazole also has a piperazine ring and normally this $\mathrm pK_\mathrm a$ is around 9.8. There are electron acceptors but I still find 2.3 to be very low. Is this correct and which of the two nitrogens will be protonated?