Tetrazoloquinolines: Synthesis, Reactions, and Applications

This review summarizes the synthesis, reactions, and biological activities of tetrazolo[1,5-a]quinoline derivatives. These derivatives were synthesized by several methods such as i) from the reaction of 2-chloroquinoline with sodium azide ii) from diazotization 2-hydrazinylquinoline derivatives, and iii) from intramolecular cyclocondensation of 2-azidoarylidenes. Also, the chemical reactions and pharmacological activities of some tetrazoloquinolines such as tetrazolo[1,5-a]quinoline-4-carbaldehyde, 5-chlorotetrazolo[ 1,5-a]quinoline, 4-(chloromethyl)tetrazolo[1,5-a]quinoline, tetrazolo[1,5- a]quinoline-4-carboxylic acid, and 5-azidotetrazolo[1,5-a]quinoline were discussed.

Thermolytic Synthesis of Naphthalenes via Intramolecular Cyclocondensation of o-Phenylallylbenzaldehydes

The development of intramolecular carbonyl-ene type cyclocondensation of oxygenated o-phenylallylbenzaldehydes in refluxing decalin is reported. The facile and easy-to-operate thermolytic rearrangement procedure generates substituted naphthalenes in good to excellent yields.

Synthesis of N,N’-Linked Isothiazolium Salts via Intramolecular Cyclocondensation of Hydrazonium Salts

Interaction of β -thiocyanatovinyl aldehydes with N-amino heterocycles leads to formation of α, β - unsaturated hydrazonium salts dependent on the functional surroundings. The latter can undergo further intramolecular cyclocondensation giving rise to N,N′-linked isothiazolium salts as the final product. The isolated hydrazonium salts, not undergoing ring formation, have s-trans conformation of the azadiene system