pseudo acids

Potentially acidic compounds that require some structural reorganization, such as keto–enol tautomerization, having a non-negligible activation energy, in order to show normal acidic properties, e.g. nitroalkanes:
P04920
Source:
PAC, 1995, 67, 1307 (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1361