Silver‐Catalyzed Direct Regioselective C3 Phosphonation of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones With H‐phosphites

Abstract

An efficient and simple protocol for silvercatalyzed direct C3 phosphonation of 4H-pyrido[1,2-a] pyrimidin-4-ones with dialkyl phosphites has been developed. The reaction shows high regioselectivity, broad scope of substrates, and good functional group compatibility. Importantly, the phosphorylated 4H-pyrido[1,2-a]pyrimidin-4-one product 3 u can be employed as efficient probes for Fe 3 + .

4H‐Pyrido[1,2‐a]pyrimidin‐4‐one, biologically important fused heterocyclic scaffold: Synthesis and functionalization

“…In 2021 , The Wang group developed an efficient silver‐catalyzed C3 phosphonation method for 4H‐pyrido[1,2‐ a ]‐pyrimidin‐4‐ones (Scheme 31) [47]. To produce the corresponding products, 4 H ‐pyrido[1,2‐ a ]pyrimidin‐4‐one and its derivatives, such as 2‐ alkyl/aryl‐4 H ‐pyrido[1,2‐ a ]pyrimidin‐4‐one 89 , were allowed to react with dialkyl phosphites 90 in the presence of silver nitrate as a catalyst in acetonitrile at 80°C in open air.…”

“…In 2021, The Wang group developed an efficient silvercatalyzed C3 phosphonation method for 4H-pyrido[1,2-a]pyrimidin-4-ones (Scheme 31) [47]. To produce the corresponding products, 4H-pyrido[1,2-a]pyrimidin-4-one and its derivatives, such as 2-alkyl/aryl-4H-pyrido [ 4H-pyrido[1,2-a]pyrimidin-4-one scaffolds are medicinally very important heterocyclic motifs.…”

Regioselective C(sp2)3−H thiocyanation of substituted 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones and its derivatizations

“…[21] Very recently, Wang and coworkers revealed a unified methodology for direct C-3 phosphonation of 4H-pyrido[1,2a]pyrimidin-4-ones with dialkylphosphites under Ag catalysis. [22] Despite these significant advancements, the direct and regioselective thiocyanation of 4H-pyrido[1,2-a]pyrimidin-4-ones at the C-3 position has never been reported. In continuation of our research interest on CÀ H functionalization, [23] herein, we disclose an elegant approach for synthesizing 3-thiocyanato derivatives of 4H-pyrido[1,2-a]pyrimidin-4-ones under mild conditions.…”

“…Very recently, Wang and coworkers revealed a unified methodology for direct C‐3 phosphonation of 4 H ‐pyrido[1,2‐a]pyrimidin‐4‐ones with dialkylphosphites under Ag catalysis [22] . Despite these significant advancements, the direct and regio‐selective thiocyanation of 4 H ‐pyrido[1,2‐ a ]pyrimidin‐4‐ones at the C‐3 position has never been reported.…”