Reaction of Methyl Thioacetate with Nitrilimines: An Experimental, Local Ionization Energy and Electrostatic Potential Investigation

Abstract

The reaction of hydrazonoyl chloride [1] precursor of nitrilimines
[2] with methyl thioacetate [3] proceeds away from the expected
cycloaddition that aimed at obtaining 1,3,4-thiadiazine-5-one [4].
Unexpectedly, the final product was acyclic adduct. The reaction
was computationally verified and compared with the reaction of
nitrilimines [2] with  α-aminoester [5] to give 4,5-dihydro-1,2,4-ttiazine-
6-ones [6]. For both reactions, the reactants, transition states
and sought products were fully optimized using the HF/6-311G
(d,p). Transition structures were tested in the existence of one imaginary
vibrational frequency. Calculated minima of local ionization
energy ( I_{S, min}) and the extrema of electrostatic potential
(V_{S, min} , V _{S, max}) of the reactants predicted and verified similar
treuds in both reactions which indicate an analogous reactivity. and
thus cyclic products [4, 6] are equally expected.