Síntese de N-heterociclos: 5-carboxialdeído-oxazóis e tetrazolo[1,5- a]quinolinas

Abstract

Heterocycle compounds are a class of organic compounds that have several biological and technological applications. In the present work, a method was developed for the synthesis of 5-carboxyaldehyde-oxazoles from the intramolecular cyclization of Npropargilamides in the

presence of selenium dioxide. This cyclization was promoted using acetonitrile as a solvent at 80 °C. Thus, through the developed method, it was possible to synthesize nine examples of 5-carboxyaldehyde-oxazoles with good to excellent yields (38-91%) and with a reaction time of 4 h. In addition, a method was developed for the synthesis of 4-(arylchalcogenyl)tetrazolo[1,5-a]quinolines from a Knoevenagel condensation between the substituted 2-azidobenzaldehyde and arylchalcogenyl-acetonitriles, followed by an intramolecular cycloaddition [3+2]. The reactions were developed in the presence of potassium carbonate as a base, using a mixture of dimethyl sulfoxide and water as a solvent at a temperature of 80 °C. In this study, eight examples of 4-(arylselanyl)tetrazolo[1,5-a]quinolines with yields of 45-98% and four examples of 4-(arilthio)tetrazolo[1,5-a]quinolines with yields of 55-62% were selectively obtained after 4 h of reaction.