Multicomponent synthesis of novel functionalized spiroindenopyridotriazine-4H-pyrans

A very convenient one-pot method for the synthesis of new biologically active compounds, spiro-4H-pyran derivatives, has been developed. This approach, enables the incorporation of three pharmacophoric cores: pyran, pyridine and triazine scaffolds, within a single molecular skeleton using an efficient sequential multicomponent reaction. The starting materials include ninhydrin, cyanoacetohydrazide, ethyl cyanoacetate, aromatic aldehydes, pyrazolone and malononitrile. In this process, spiropyran derivatives were produced with high efficiency through three consecutive reactions. The first step involves the synthesis of 1,6-diaminopyridinone via a three-component approach using readily available starting materials. The second step, the synthesis of pyridotriazine, occurs in a domino way without the need to separate the intermediate product of the first step. Finally, the third step involves the synthesis of new spiro-4H-pyran derivatives through a one-pot three-component reaction. This method offers several advantages, including fast and simple purification of products, the use of safe solvents, no need for metallic and toxic catalysts, high atomic economy and excellent chemoselectivity of the reactions.