One-pot synthesis and structure of isomeric aryl-substituted triazolohexahydroquinazolines

Abstract

Aryl-substituted triazolohexahydroquinazolines have been synthesized by means of three-component condensation of pnitro(pbromo) benzaldehydes, cyclohexanone, 1,2,4-triazol-3-amine. A scheme of the reaction mechanism is proposed, which makes it possible to explain the features of the behavior of p-nitro(bromo) benzaldehydes in condensation reactions in comparison with their ortho-substituted analogs. It has been found that the movement of the substituent from the ortho- tо -para-position of the benzene ring while maintaining the general direction of the reaction has a decisive effect on the number and ratio of the formed isomers and leads to the absence of hydroxylated forms of triazolohexahydroquinazolines. The composition and structure of the products have been confirmed by the data of elemental analysis, IR and one-dimensional, two-dimensional NMR spectroscopy. One-pot synthesis of aryl-substituted triazohexahydroquinazolines is a non-selective process that leads to a mixture of isomers, the structure and ratio of which is determined by the nature and position of the substituent groups in the aldehyde component.