Recent advances in the synthesis of (hetero)aryl-substituted heteroarenes via transition metal-catalysed direct (hetero)arylation of heteroarene C–H bonds with aryl halides or pseudohalides, diaryliodonium salts, and potassium aryltrifluoroborates

Meso-ionic heterocycles (1976–1980)

Syntheses and evaluation of antioxidant activity of sydnonyl substituted thiazolidinone and thiazoline derivatives

Transition-Metal-Catalyzed Direct C–H Alkenylation, Alkynylation, Benzylation, and Alkylation of (Hetero)arenes

Isatin derivatives and their anti-bacterial activities.

3-Arylsydnones ( Ia – u ) have been converted into the corresponding 3-aryl-5-methyl-1,3,4-oxadiazolin-2-ones ( IIIa – u ) by a single-step reaction with bromine in acetic anhydride. In the preliminary screening of all these compounds, the halogen-substituted derivatives have shown antimicrobial activities equal to those of the standard drugs used.

Transformation of the sydnone ring into oxadiazolinones. A convenient one-pot synthesis of 3-aryl-5-methyl-1,3,4-oxadiazolin-2-ones from 3-arylsydnones and their antimicrobial activity

The α-β-unsaturated ketones of 3-arylsydnones (Ia–y) were treated with 1,2-phenylenediamine to obtain the 3-aryl-4-[2′-aryl-2′,4′,6′,7′-tetrahydro-(1′H)-1′,5′-benzodiazepine-4′-yl]sydnones (IIa–y) in high yield. All the new compounds synthesised were screened for antibacterial and antifungal activities.

1,5-Benzodiazepine derivatives of 3-arylsydnones: synthesis and antimicrobial activity of 3-aryl-4-[2′-aryl-2′,4′,6′,7′-tetrahydro-(1′H)-1′,5′-benzodiazepine-4′-yl]sydnones

Green chemistry is the utilization of a set of principles that will help reduce the use and generation of hazardous substances during the manufacture and application of chemical products. Green chemistry aims to protect the environment not by cleaning up, but by inventing new chemical processes that do not pollute. It is a rapidly developing and an important area in the chemical sciences. Principles of green chemistry, developments in this field and some industrial applications are discussed.

Concept of green chemistry

Mesoionic compounds are distinct types of heterocycles which belong to the class of nonbenzenoid aromatics. Sydnone, the representative mesoionic compound has been extensively studied because of its unusual structure, chemical properties and synthetic utility. Sydnone is used as a versatile synthon in heterocyclic synthesis. This article gives a brief account of the comparative studies of the structural features of mesoionic compounds and other heteroaromatic systems. Some synthetically useful tandem reactions of sydnones are also discussed.

http://link.springer.com/content/pdf/10.1007/BF02835674.pdf

Mesoionic compounds: An Unconventional Class of Aromatic Heterocycles

Some hitherto unknown novel bismesoionic compounds, 3-[4/3 (5H/substituted- 2-sulphido-1,3,4-thiadiazolium-4 carbonyl)phenyl]sydnones 5a–d and 6a-d and 4-[4 (5H/substituted-2-sulphido-1,3,4-thiadiazolium)benzoyl] (5H/substituted-1,3,4-thiadiazolium- 2-thiolates 9a–d have been synthesized from 3-[(hydrazinocarbonyl)phenyl] sydnones 1 and 2. A few of these compounds exhibited in vitro antitubercular activity and also antimicrobial activity higher than the employed reference drugs.

http://www.doiserbia.nb.rs/ft.aspx?id=0352-51390609851J

Sydnone derivatives as synthons for novel bismesoionic compounds. Synthesis of 3-(2-sulphido-1,3,4-thiadiazolium-4-carbonylphenyl) sydnones and 4-[4-(2-sulphido-1,3,4-thiadiazolium)benzoyl]- 1,3,4-thi

Bharati V. Badami

Papers

Transformation of the sydnone ring into oxadiazolinones. A convenient one-pot synthesis of 3-aryl-5-methyl-1,3,4-oxadiazolin-2-ones from 3-arylsydnones and their antimicrobial activity

1,5-Benzodiazepine derivatives of 3-arylsydnones: synthesis and antimicrobial activity of 3-aryl-4-[2′-aryl-2′,4′,6′,7′-tetrahydro-(1′H)-1′,5′-benzodiazepine-4′-yl]sydnones

Concept of green chemistry

Mesoionic compounds: An Unconventional Class of Aromatic Heterocycles

Sydnone derivatives as synthons for novel bismesoionic compounds. Synthesis of 3-(2-sulphido-1,3,4-thiadiazolium-4-carbonylphenyl) sydnones and 4-[4-(2-sulphido-1,3,4-thiadiazolium)benzoyl]- 1,3,4-thi