@M03842@ having the 1,2,3-oxadiazole skeleton bearing an oxygen atom attached to the 5 position.
(These structures represent only two canonical forms).
Source: PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1370 [Terms] [Paper]
Citation: 'sydnones' in IUPAC Compendium of Chemical Terminology, 3rd ed. International Union of Pure and Applied Chemistry; 2006. Online version 3.0.1, 2019. https://doi.org/10.1351/goldbook.S06207 RISBibTexEndNote