Serendipitous Access to Aryl Keto-Imidazo[1,5-a]pyrazines
Тип публікації :
Препринт
Дата випуску :
6 липня 2026 р.
Автор(и) :
Sergey V. Ryabukhin
Svitlana V. Stetsenko
Andriy I. Frolov
Galyna P. Grabchuk
Olexandr Ye. Pashenko
Dmytro M. Volochnyuk
eKNUTSHIR URL :
Журнал :
ChemRxiv
Цитування :
[APA 7] Sergey, V. R., Svitlana, V. S., Andriy, I. F., Galyna, P. G., Olexandr, Y. P., & Dmytro, M. V. (2026). Serendipitous Access to Aryl Keto-Imidazo[1,5-a]pyrazines. ChemRxiv,. https://doi.org/10.26434/chemrxiv.15005744/v1
[ДСТУ] Serendipitous Access to Aryl Keto-Imidazo[1,5-a]pyrazines / V. R. Sergey та ін. ChemRxiv. 2026. DOI: 10.26434/chemrxiv.15005744/v1 (дата звернення: 11.09.2026).
In the course of the geminal bisamides production using chlorotrimethylsilane (TMSCl)/DMF-promoted condensations of α-azine carboxamides with aldehydes, pyrazine-2carboxamide exhibited unexpected reactivity, undergoing cyclocondensation with aldehydes to afford 3-substituted imidazo[1,5-a]pyrazin-1(7H)-ones rather than the anticipated bisamide products. This new reaction provides direct synthetic access to previously unreported ketoimidazo[1,5-a]pyrazines from readily available pyrazine carboxamides and aldehydes. Under the optimized conditions, aryl, heteroaryl, and aliphatic aldehydes underwent the transformation, while preliminary tests with substituted pyrazine carboxamides indicated that modification of the azine component is also possible. Even under the parallel chemistry protocol, isolated yields reached 72% after preparative HPLC purification. Unexpectedly, the products were assigned as keto tautomers, a finding confirmed by single-crystal X-ray diffraction. These results establish a new cyclocondensation pathway and suggest a promising route to related annulated azine heterocycles.
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