The irradiation of water solution of 6-azauracil showed that one of the photoreactions is the phototautomerization of the oxo tautomer of the compound into the hydroxy tautomer. The photoreaction was identified by a thorough analysis of experimetally obtained UV-spectra and the theoretical spectra simulation of several hydroxy tautomers of the compound. Furthermore we performed DFT level (BLYP/aug-cc-pVDZ) investigations of the mechanism of phototautomerization of the oxo tautomer of 6-azauracil in water surroundings applying PCM. The complete excited-state reaction path of the mechanism was proposed. It was found that the phototautomerization occurs along the ¹πσ^∗ excited-state reaction path. This reaction path was found to connect the two conical intersections S₀/S₁ of the H-detachment processes in the oxo and hydroxy tautomers of 6-azauracil.

6-氮杂尿嘧啶水溶液的辐照表明，光反应之一是化合物的羰基互变异构体向羟基互变异构体的光互变异构。通过对实验获得的紫外光谱进行彻底分析，并对该化合物的几种羟基互变异构体进行理论光谱模拟，从而确定了光反应性。此外，我们进行了DFT级研究（BLYP / aug-cc-pVDZ），研究了使用PCM在水环境中6-氮杂尿嘧啶的羰基互变异构体的光互变异构机理。提出了该机理的完整激发态反应路径。据发现，所述phototautomerization沿发生¹ πσ ^*激发态反应路径。发现该反应路径连接了两个圆锥形交点S ₀/ S ₁在6-氮杂尿嘧啶的羰基和羟基互变异构体中的H-分离过程。