Huraian
This research revealed that the numbers of available heterocyclic compounds are mainly focused on nitrogen-containing compounds, such as quinazolines, indoles, benzimidazole, quinoxalines, coumarins, and pyrimidines, etc. A mixture of substituted aldehydes (0.01 mol) like acetylacetone (method 1) or ethyl acetoacetate (method 2), urea or thiourea (0.01 mol) and lemon juice (0.5 ml) were taken into a round bottom flask and reflux for 1 hour under continuous stirring.