Thermal decomposition of 2H-[1, 2, 4] oxadiazolo [2, 3-a] pyridine-2-thione afforded 3-(2-pyridyl)-2H-pyrido [1, 2-a]-1, 3, 5-triazine-2, 4 (3H)-dione and 1, 3-di (2-pyridyl) urea, and similar decomposition of its pyridazine analog afforded 3-(3-pyridazinyl)-2H-pyridazino [1, 6-a]-1, 3, 5-triazine-2, 4 (3H)-dione and 1, 3-di (3-pyridazinyl) urea. Aza-heteroaromatic α-isocyanates, which are intermediates in the decomposition, were utilized for the synthesis of unsymmetrical 1, 3-disubstituted ureas.
2H-[1, 2, 4]噁二唑[2, 3-a]
吡啶-2-
硫酮的热分解生成了3-(2-
吡啶基)-2H-
吡啶[1, 2-a]-1, 3, 5-三嗪-2, 4(3H)-二酮和1, 3-二(2-
吡啶基)
脲,而其
吡唑类似物的类似分解则生成了3-(3-
吡唑基)-2H-
吡唑[1, 6-a]-1, 3, 5-三嗪-2, 4(3H)-二酮和1, 3-二(3-
吡唑基)
脲。在分解过程中产生的氮杂杂环α-
异氰酸酯被用于合成不对称的1, 3-二取代
脲。