Synthesis, spectral characteristics and molecular structure of 2H‐1,3,5‐oxadiazine‐2,4(3H)‐diimine derivatives

Abstract

In this work, we report the synthesis of 2H‐1,3,5‐oxadiazine‐2,4(3H)‐diimine derivatives based on acylated thioureas. The method for the preparation of 1,3,5‐oxadiazine derivatives is based on the reaction of dehydrosulfurization of the starting acylated thioureas under the action of dicyclohexylcarbodiimide (DCC) followed by the [4 + 2] cycloaddition reaction of another DCC molecule to the resulting intermediate carbodiimide. The structure of the obtained derivatives of 1,3,5‐oxadiazine was confirmed by 1H, 13C NMR, IR spectroscopy, mass spectrometry, and x‐ray diffraction analysis.

Exploring the latest trends in chemistry, structure, coordination, and diverse applications of 1-acyl-3-substituted thioureas: a comprehensive review

“…The resulting acyl carbodiimide undergoes [4 + 2] Diels-Alder cycloaddition reaction with another molecule of DCC afford 2H-1,3,5-oxadiazine-2,4(3H)diimine derivatives (30a-g). 52 afford desired 2-aminothiazole derivatives (34F1-30) (Scheme 9). 53 Cyclization of pivaloyl thiourea (35) to 5-(tert-butyl)-N-(2,4dichlorophenyl)-1H-1,2,4-triazol-3-amine (36) was carried out by reacting pivaloyl thiourea (35) with hydrazine hydrate in ethanol at room temperature (Scheme 10).…”

“…It was found that the oxadiazine ring in the molecule was at with an accuracy of 0.03 Å (Scheme 8). 52 5-(Tert-butyl)-N-(2,4-dichlorophenyl)-1H-1,2,4-triazol-3amine (36) crystallized in orthorhombic crystal system with Pbca space group. Crystal structure stability of the molecule was due to the presence of intermolecular N-H/N hydrogen bonds and p/p stacking interaction between B rings (Scheme 10).…”

“…It was found that the oxadiazine ring in the molecule was flat with an accuracy of 0.03 Å ( Scheme 8 ). 52 …”

“…The resulting acyl carbodiimide undergoes [4 + 2] Diels–Alder cycloaddition reaction with another molecule of DCC afford 2 H -1,3,5-oxadiazine-2,4(3 H )-diimine derivatives ( 30a–g ). 52…”