Synthesis and HPLC/MS Investigation of 2-Alkyl-5-Phenyl-4,5,6,7-Tetrahydro-[1,2,4]triazolo[1,5-a]pyrimidinol Derivatives from Vegetable Oils

Abstract

This work presents the synthesis and analysis of 2-alkyl-5-phenyl-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-a]pyrimidin-7-ol derivatives obtained from sunflower, palm, and coconut oils. The synthetic approach included the preparation of aminotriazoles followed by their condensation with cinnamaldehyde in the presence of an amphoteric surfactant. The composition and structure of the reaction mixtures were established using high-resolution HPLC/ESI-MS. It was shown that the distribution of the target products correlates with the fatty acid profile of the starting oil: linoleic acid derivatives dominated in sunflower oil (59.41%), palmitic acid

 derivatives in palm oil (52.67%), and lauric acid derivatives in coconut oil (43.51%). The presence of side products (3-8%) was observed, attributed to incomplete cyclization, aldehyde self-condensation, and the specifics of obtaining 2-alkyl-5-phenyl-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-a]pyrimidin-7-ols without isolation (motivated by the intended use of these products as acid corrosion inhibitors for steel). The results confirm the potential of using renewable plant-based raw materials for the targeted synthesis of heterocyclic compounds with potential inhibitory activity against metal acid corrosion.