An easy, highly efficient, and simple one-pot approach for the synthesis of dihyroindeno[1,2-b]pyrroles and indeno[2¢,1¢:4,5]pyrrolo[1,2-a]-fused 1,3-diazaheterocycles under mild conditions is reported. The reaction of a primary amine or 1,n-diamine with 1,1-bis(methylthio)-2-nitroethene in the presence of ninhydrin in aqueous media afforded the title compounds in good yields.

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A novel and tandem synthesis of highly functionalized tetrahydroindeno[1,2-d]imidazole is described. A one-pot reaction between a primary amine, an aryl isothiocyanate, and ninhydrin leads to highly substituted indeno[1,2-d]imidazoles under solvent-free conditions in excellent yields (Scheme). Their structures were corroborated spectroscopically (IR, 1 H-and 13 C-NMR, and EI-MS) and by elemental analyses.Introduction. -2-Substituted dihydroimidazoles are of increasing interest because of their applications [1] as disinfectants, pharmaceuticals, and also because of their applications in supramolecular-chemistry preparation of molecular tectonics [2]. Especially, imidazole-2-thiones and their derivatives have received attention because of their bioactivities and application for pharmaceutical synthesis. Thus, the presence of an imidazole ring in natural products and pharmacologically active compounds has instituted a diverse array of synthetic approaches to these heterocycles [3].

The hitherto unreported, highly functionalized 1H-pyrazole-3-carboxylates 3 have been synthesized in good yields via a one-pot three-component domino reaction of phenylhydrazines, dialkyl acetylenedicarboxylates, and ninhydrin under mild conditions for the first time. No co-catalyst or activator is required for this multicomponent reaction, and the reaction is, from an experimental point of view, simple to perform (Scheme 1). The structures of compounds 3 were corroborated spectroscopically (IR, 1 H-and 13 C-NMR, and EI-MS) and by elemental analyses. A plausible mechanism for this type of cyclization/addition reaction is proposed (Scheme 2).Introduction. -The synthesis of pyrazole derivatives has received considerable attention due to their broad spectrum of biological activities [1]. Although there are many reports related to the synthesis of pyrazoles in the literature, a search revealed that the synthesis of pyrazole derivatives with an indene moiety have not been described.