Photoinduced and Thermal Denitrogenation of Bulky Triazoline Crystals: Insights into Solid-to-Solid Transformation

The photoinduced and thermal denitrogenation of crystalline triazolines with bulky substituents leads to the quantitative formation of aziridines in clean solid-to-solid reactions despite very large structural changes in the transition from reactant to product. Analysis of the reaction progress by powder X-ray diffraction, solid-state ¹³C CPMAS NMR, solid-state FTIR spectroscopy, and thermal analysis has revealed that solid-to-solid reactions proceed either through metastable phases susceptible to amorphization or by mechanisms that involve a reconstructive phase transition that culminates in the formation of the stable phase of the product. While the key for a solid-to-solid transformation is that the reaction occurs below the eutectic temperature of the reactant and product two-component system, experimental evidence suggests that those reactions will undergo a reconstructive phase transition when they take place above the glass transition temperature

Aziridine Nitrogen Inversion by Dynamic NMR: Activation Parameters in a Fused Bicyclic Structure

The nitrogen inversion of a <i>N</i>-phenyl aziridine fused to a succinimide ring is influenced by the presence of a phenyl ring in the succinimide moiety. The endo invertomer is favored, showing an unsymmetrical equilibrium in variable ¹H NMR studies

Facile synthesis of aminonaphthoquinone Mannich bases by noncatalytic multicomponent reaction

<p>Mannich bases are formed in a noncatalytic multicomponent reaction, which is promoted by ultrasound irradiation. The procedure avoids the use of toxic solvents, catalyst, and purification, generating the desired compounds in excellent yields and short reaction times.</p