Acylation of 3‐phenylsydnone with carboxylic acids and phosphorus pentoxide

Fluorine bearing sydnones with styryl ketone group: synthesis and their possible analgesic and anti-inflammatory activities

“…The starting material, 4-acetyl-3-(3-chloro-4-fluorophenyl)sydnone 1, was prepared by the action of glacial acetic acid on 3-(3-chloro-4-fluorophenyl)sydnone in presence of phosphorous pentoxide 18 ; the 3-(3-chloro-4-fluorophenyl)sydnone itself was synthesized by literature protocol from 3-chloro-4-fluoroaniline 19 . The IR spectrum of compound 1 showed sydnone C=O and acetyl C=O stretching at 1772 and 1671 cm −1 , respectively, and in 1 H-NMR spectrum, it showed a singlet at δ 2.54 corresponding to three hydrogens of COCH 3 and a multiplet at 7.61-7.89 accounting three aromatic protons (data not shown).…”

Novel One‐Pot Synthesis of Aziridines Containing Sydnone Moiety

“…[14] 3-Substituted-4-acetylsydnone was prepared according to the procedures reported in literature. [15] A probable mechanistic pathway for the formation of aziridine quinoxaline 3 is shown in Scheme 2.…”

Mesoionic Sydnone: A Review in Their Chemical and Biological Properties

“…Another characteristic component of the sydnone NMR spectra is the peak of the carbon C5 which appears in the lowest field of 13 Greco and his co-workers reported unsuccessful attempts to acylate the sydnone ring in the conventional Friedel-Crafts reaction using many catalysts such as aluminum chloride, stannic chloride, and phosphoric acid. However, they successfully prepared a variety of 4-acylsydnone derivatives when phosphorous pentoxide (3 equiv) was refluxed with one molar equivalent of carboxylic acid and sydnone [29]. Later, other chemists speculated that the failure of FriedelCrafts acylation was due to the coordination between Lewis acid and the exocyclic oxygen of the sydnone which eventually yielded a sydnone-containing fused ring compounds rather than the desired acylated product as shown in Scheme 3 [30].…”