Sydnone
Chemical compound
From Wikipedia, the free encyclopedia
Sydnones are mesoionic heterocyclic chemical compounds possessing a C5-oxygenated 1,2,3-oxadiazole core,[1][2][3] named after the city of Sydney, Australia. Like other mesoionic compounds they are dipolar, possessing both positive and negative charges which are delocalized across the ring.
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| Names | |
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| IUPAC name
2H-Oxadiazol-5-one | |
| Other names
1,2,3-Oxadiazol-5(2H)-one | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
PubChem CID |
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| Properties | |
| C2H2N2O2 | |
| Molar mass | 86.050 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Discovery
N-phenylsydnone was first prepared in 1935 by John Campbell Earl and Alan W. Mackney by cyclodehydration of N-Nitroso-N-phenylglycine with acetic anhydride.[4] Later work showed that this could be applied fairly generally to the nitrosamines of N-substituted amino acids.[2]
The parent compound sydnone is not synthetically accessible and may not exist.[2]: 130 [3]: 554
Chemical structure
Sydnones have the following resonance structures.[citation needed] The exocyclic oxygen atom (O6) has a significant negative charge.[3]
Recent computational studies have indicated that sydnones and other similar mesoionic compounds are nonaromatic, "though well-stabilized in two separate regions by electron and charge delocalization."[5]
Examples
- Cefanone (Cephanone)
- Ipramidil
- 3-Thiomorpholino-sydnonimine U.S. patent 4,332,801
- The reaction between methyl 3-benzyl-sydnone-4-acetate and diphenylacetylene is described in Ex1 of GB 1387306 gives an analog of Bufezolac.
- Synthesis and Biological Evaluation of Coumarinyl Sydnone Derivatives.[6]
Related compounds
A sydnone imine in which the keto group of sydnone (=O) has been replaced with an imino (=NH) group can be found as a substructure in the stimulant drugs feprosidnine and mesocarb.