A one‑pot synthetic strategy for the construction of chromenoimidazopyridines and chromenopyridopyrimidines containing intramolecular hydrogen bonds

Chromen-2-ones are embedded in a number of natural products and pharmaceuticals. Chromen-2-ones with a fused N-ring are frequently found in natural products as lamellarin and ningalin B. As one category of chromen-2-ones with a fused N-ring, chromenopyridines have gained increasing interest due to their broad spectrum of bioactivities. For example, they are known as antibacterial and nonsteroidal progesterone receptor modulators. Considering the importance of chromenopyridines, and based on our continued interest in the one-pot synthesis of heterocycles, herein we wish to report the efficient synthesis of chromenopyridines from the reaction of 1,1-bis(methylsulfanyl)-2- nitroethene, diamines 1, and 4-chloro-2-oxo-2H-chromene-3-carbaldehyde. We used a one-pot sequential three-component procedure for the synthesis of chromenopyridopyrimidines 2 in EtOH at room temperature which resulted in the products with excellent yields (67%) in short reaction times.