Triazolyl Derivatives for Acidic Release of Alcohols

New triazolyl-based carbonates and ethers have been investigated as potential alcohol-releasing systems under mild acidic conditions. Triazolyl carbonates could not be prepared because of their apparent instability, whereas ethers were successfully obtained. The rate of hydrolysis of these ethers ramged from a few hours to several days. A theoretical investigation demonstrated that the acidic release of alcohols from triazole derivatives proceeds first by protonation of the triazole ring followed by proton transfer from the triazole ring to the carbonyl group of the carbonates or to the oxygen atom of the ether derivatives. The rate of the decomposition reaction was shown to depend on the length of the N3–H···O hydrogen bond in the intermediate C-NH+/E-NH+ structures and on the stability of the triazole carbocation, which is closely related to the π-donating effect of its R2 and R3 substituents.