Lime juice as an efficient and green catalyst for the synthesis of 6-amino-4- aryl-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile derivatives

A new and green method for the one-pot four-component synthesis of highly functionalized 6-amino-4-aryl-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles was developed using hydrazine monohydrate or phenylhydrazine , ethylacetoacetate, malononitrile and arylaldehydes under thermal solvent-free conditions in the presence of lime juice as catalyst. The reaction proceeds smoothly to generate corresponding product. The use of non-toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are the advantages of this method.