Attempted synthesis of esters of tricarballylic acid and 3,5-dibromosalicylic acid. Structure and properties of tricarballylic acid, its anhydrides and some of their derivatives, and an investigation of the reaction pathways of anhydride formation by 1H NMR spectroscopy, MNDO and molecular mechanics methods

Abstract

Reactions ordinarily leading to the formation of esters of carboxy acids afford, in the case of tricarballylic acid, the cyclic anhydride. A comparison of the experimental and simulated ¹H NMR spectra reveals that the product contains a five-membered ring structure. To explain the experimental findings, theoretical calculations were performed at the level of molecular mechanics and MNDO methods, in order to obtain information on the structure and thermodynamic stability of various substrate conformations and reaction products, as well as on the reaction pathways of anhydride formation. Theoretical predictions reveal that the formation of the five-membered ring structure is preferred in the case of tricarballylic acid anhydride.