Quinazolines. Part IX. Covalent hydration in the neutral species of substituted quinazolines

Abstract

The ratios of hydrated to anhydrous neutral species of twenty-eight quinazolines are found to be in the range 10^–2–10^–5. The effects of substituents on this ratio in the neutral species are shown to be comparable to those observed in the respective cations, and suggest that the factors influencing the amount of hydration in these two species are similar. The ionisation constants of the hydrated species of thirty-two quinazolines have been measured and the effects of substituents on these constants are discussed.