isoureas

https://doi.org/10.1351/goldbook.I03356
The imidic acid tautomer of urea,
H2NC(=NH)OH
, and its @[email protected] 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 [Terms] [Paper]