One-Pot Three-Component Heterocyclizations of 5,6-Dihydro-1H-pyrrolo[3,2,1-ij]quinolone-1,2(4H)-dione, 6-Aminouracil Derivatives and Dimedones in Water

Multicomponent reactions (MCRs) became increasingly useful tools for the synthesis of biologically active compounds. These reactions enable multi-step syntheses to be conducted in a One-Pot fashion to obtain a variety of invaluable products. Moreover, MCRs can dramatically reduce the generation of chemical waste and reduce the cost of the starting materials [1]. Uracil and its annelated analogs occupy a unique place in the field of medicinal chemistry as useful anticancer and antiviral drugs [2]. The versatility of uracil derivatives for the synthesis of nitrogen-containing heterocycles of biological importance has been well documented in the literature [3]. As a part of our continued interest to the synthesis of novel spirocyclic compounds [4-6] we decided to examine One-Pot , p-TSA catalyzed reaction of 5,6-dihydro-1H-pyrrolo[3,2,1-ij]quinolone-1,2(4H)-dione 1, 6-amino uracil 2a and 1,3- dicarbonyl compound 3a in refluxing H2O.Evidence for the compound 4a came from a study of the H-nmr spectra of the product. Encouraged by this success, we extended this reaction to various dimedones 3b-c and 6-aminthiouracil 2b under similar conditions, furnishing the compounds 4b–e in good yields.