Sydnone Explained

Sydnones are mesoionic heterocyclic chemical compounds possessing a 1,2,3-oxadiazole core with a keto group in the 5 position.^[1] ^[2] Like other mesoionic compounds they are di-polar, possessing both positive and negative charges which are delocalized across the ring. 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."^[3] Sydnones are heterocyclic compounds named after the city of Sydney, Australia.

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.

Discovery

Sydnone was first prepared in 1935 by Earl & 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.

Examples

Cefanone (Cephanone)
Ipramidil
3-Thiomorpholino-sydnonimine
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.^[5]

References

Sydnone anions and abnormal N-heterocyclic carbenes of O-ethylsydnones. Characterizations, calculations and catalyses. . S. Wiechmann . T. Freese . M. H. H. Drafz . E. G. Hübner . J. C. Namyslo . M. Nieger . A. Schmidt . Chem. Commun. . 50 . 11822–11824 . 2014 . 80 . 10.1039/C4CC05461J . 25156208 . free.
Synthesis of Sydnones and Sydnone Imines . Claude V. Greco . Wayne H. Nyberg . C. C. Cheng . Journal of Medicinal Chemistry . 5 . 4 . 861–865 . 1962 . 10.1021/jm01239a022 . 14056419 .
Meso-ionic compounds . Wilson Baker . W. D. Ollis . Quarterly Reviews, Chemical Society . 11 . 15–30 . 1957 . 10.1039/QR9571100015 . 96888271 .
The Preparation of Substituted Hydrazines. I. Alkylhydrazines via Alkylsydnones . Joseph Fugger . Jack M. Tien . I. Moyer Hunsberger . . 77 . 7 . 1843–1848 . 1955 . 10.1021/ja01612a039 .
The Preparation of Substituted Hydrazines. II.1 3-Pyridylhydrazine via the Phototropic N-(3-Pyridyl)-sydnone . Jack M. Tien . I. Moyer Hunsberger . . 77 . 24 . 6604–6607 . 1955 . 10.1021/ja01629a052 . 88, 178 (1961);
Sydnones. III. Preparation and Interconversion of Mercurated Derivatives of N-(3-Pyridyl)-sydnone1-3a . Jack M. Tien . I. Moyer Hunsberger . . 83 . 1 . 178–182 . 1961 . 10.1021/ja01462a035 .
. Chem. Ind. . 521 . 1955 ., ;
Some new mesoionic compounds . Alexander Lawson . D. H. Miles . J. Chem. Soc. . 2865–2871 . 1959 . 10.1039/JR9590002865 .
A Kinetic Study of the Reaction of a "Meso-ionic" Compound (Dehydrodithizone) with Haloacetates . J. Ogilvie . V. K. Miyamoto . Thomas C. Bruice . . 83 . 11 . 2493–2495 . 1961 . 10.1021/ja01472a017 .
A New Class of Central Nervous System Stimulants . LEMONT B. KIER, LAURETTA E. FOX, D. DHAWAN & I. W. WATERS . Nature . 195 . 4843 . 817–818 . 1962 . 10.1038/195817a0 . 14455827 . 1962Natur.195..817K . 1683698 .

External links

Notes and References

Stewart. F. H. C.. The Chemistry of the Sydnones. Chemical Reviews. 1 April 1964. 64. 2. 129–147. 10.1021/cr60228a004.
Browne. Duncan L.. Harrity. Joseph P.A.. Recent developments in the chemistry of sydnones. Tetrahedron. January 2010. 66. 3. 553–568. 10.1016/j.tet.2009.10.085.
Simas. Alfredo. Are mesoionic compounds aromatic?. Canadian Journal of Chemistry. 1998. 76. 6 . 869–872. 10.1139/v98-065.
Earl. J. Campbell. Mackney. Alan W.. 204. The action of acetic anhydride on N-nitrosophenylglycine and some of its derivatives. Journal of the Chemical Society (Resumed). 1935. 899. 10.1039/jr9350000899.
Patel. Keshav C.. Patel. Himanshu D.. Synthesis and Biological Evaluation of Coumarinyl Sydnone Derivatives. e-Journal of Chemistry. 8. 1. 2011. 113–118. 0973-4945. 10.1155/2011/705856. free.