The Synthesis and Thermolysis of Triazolines, Triazolinones and Triazolinethiones

Abstract

<p>The purpose of this work was to synthesize new triazolines utilizing the lead tetraacetate oxidation method, to establish the mechanism of cyclization and to explore thermal and photochemical decompositions of some triazolines.</p> <p>The first part of this thesis describes the preparation of two new triazolines (3,3-dimethyl-5-imino-Δ¹-1,2,4-triazoline and 3,3-dimethyl-4-phenyl-5-phenylimino-Δ¹,1,2,4-triazoline) achieved by lead tetraacetate oxidation. The mechanism of LTA cyclization is discussed in the relation to the mechanisms of lead tetraacetate oxidations of semi-carbazones. The second part deals with thermal decomposition studies of 3,3-dimethyl-4-phenyl-5-phenylimino-Δ¹-1,2,4-triazoline, 3,3-dimethyl-4-phenyl-Δ¹-1,2,4-triazoline-5-thione and 3,3-dimethyl-4-phenyl-Δ¹,2,4-triazolin-5-one. Possible mechanisms of the decomposition are discussed in the light of a correlation between the rate constants, activation parameters, substituent constants and solvent effects. Exploratory work in the photochemical decomposition of 3,3-dimethy-4-phenyl-Δ¹-1,2,4-triazolin-5-one is presented in the third part.</p>