The imidic acid tautomer of urea,
H2NC(=NH)OH
, and its hydrocarbyl derivatives.
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1345 (https://doi.org/10.1351/pac199567081307)