Sydnone

Sydnone

File:Sydnone circle structure.png
Names
IUPAC name 2H-Oxadiazol-5-one
Other names 1,2,3-Oxadiazol-5(2H)-one
Identifiers
CAS Number	534-24-7
3D model (JSmol)	Interactive image
ChemSpider	65792731
ECHA InfoCard
E number
PubChem CID	12443168
CompTox Dashboard (EPA)	{{#property:P3117}}
InChI InChI=1S/C2H2N2O2/c5-2-1-3-4-6-2/h1,4H Key: BIGWXAGEQONZGD-UHFFFAOYSA-N
SMILES C1=NNOC1=O
Properties
Chemical formula	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). Infobox references

Sydnones are mesoionic heterocyclic chemical compounds possessing a C5-oxygenated 1,2,3-oxadiazole core, 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.

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. Later work showed that this could be applied fairly generally to the nitrosamines of N-substituted amino acids.

The parent compound sydnone is not synthetically accessible and may not exist.

Chemical structure

Sydnones have the following resonance structures. The exocyclic oxygen atom (O6) has a significant negative charge. File:Sydnone Resonance Structures.svg

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."

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.

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.

See also

• Chemical compounds with unusual names
• Montréalone
• Münchnone
• Sydnone imine

References

• 88, 178 (1961);
• , ();

External links

• IUPAC Goldbook entry
• Dictionary of Organic Compounds