A theoretical study of the gas phase (proton affinity) and aqueous (pKa) basicity of a series of 150 pyrazoles

摘要: This study deals with the basicity, both in gas phase and an aqueous solution, of a set 150 pyrazoles covering range about 200 kJ mol−1 proton affinity 10–15 pKa units. There are 63 NH-pyrazoles, many cases, two different tautomers 87 N-substituted pyrazoles. The results well reproduced by DFT theoretical calculations when less stable removed. For values to be adequately calculations, some need removed, use dummy variables accounting for protonation on exocyclic amine groups is required conformation 5-phenyl considered. Using these restrictions large number unknown pKas can predicted few errors corrected.