An Efficient Synthesis of Chromeno[2,3-d]pyrimidine-2,4-diones with a Nitroketene-Aminal Moiety at C(5) by a One-Pot Four-Component Reaction

An efficient and novel synthesis of chromeno[2,3‐d]pyrimidine‐2,4‐dione derivatives with a nitroketene‐aminal moiety at C(5) via four‐component reaction of salicylaldehydes, barbituric acid, diamines, and 1,1‐bis(methylsulfanyl)‐2‐nitroethene in EtOH and in the presence of AcOH is reported. Easy performance, good yields, and easy purification are the main advantages of this method. All structures were confirmed by IR, MS, and 1H‐ and 13C‐NMR, and by X‐ray crystal‐structure analyses. A plausible mechanism for this type of reaction is proposed (Scheme).