Luecke, Ana-Luiza published the artcilePalladium complexes of anionic N-heterocyclic carbenes derived from sydnones in catalysis, Quality Control of 52431-30-8, the publication is Zeitschrift fuer Naturforschung, B: A Journal of Chemical Sciences (2016), 71(6), 643-650, database is CAplus.
The anion of N-phenylsydnone, which can be generated on treatment of N-phenylsydnone with cyanomethyllithium without decomposition, can be represented as tripolar zwitterionic and as anionic N-heterocyclic carbene resonance forms. Its Pd complex was prepared from 4-bromo-3-phenylsydnone and tetrakis(triphenylphosphine)palladium and is active as catalyst in Suzuki-Miyaura reactions. Thus, 2,5-dibromo-3,4-dinitrothiophene was effectively converted into 2,5-diaryl-3,4-dinitrothiophenes with 1-naphthyl-, (4-trifluoromethoxy)phenyl-, [4-(methylsulfanyl)phenyl]- and (biphenyl-4-yl)boronic acid. 3-(Phenanthren-9-yl)quinoline was prepared by Suzuki-Miyaura reaction starting from 3-bromoquinoline. 1-Chloro-2,4-dinitrobenzene cross-coupled with Ph boronic acid, 1-naphthylboronic acid and 9-phenanthrylboronic acid. 4-Bromobenzylic alc. gave (4-isopropylphenyl)methanol on sydnone-Pd complex-catalyzed reaction with iso-Pr boronic acid.
Zeitschrift fuer Naturforschung, B: A Journal of Chemical Sciences published new progress about 52431-30-8. 52431-30-8 belongs to bromides-buliding-blocks, auxiliary class Liquid Crystal &OLED Materials, name is 2,5-Dibromo-3,4-dinitrothiophene, and the molecular formula is C4Br2N2O4S, Quality Control of 52431-30-8.
Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary