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Reactions of indole-2,3-diones with biuret afforded 1,3-dihydro-3-ureidoformimido-2H-indol-2-ones and spiro[3H-indole-3,2′(1′H)-(1,3,5)triazine]-2,4′,6′(1H,3′H,5′H)-triones indicated these to be solvent dependent. The chemical structures of the products were elucidated by their comprehensive spectroscopic (IR, 1H-NMR, 13C-NMR, 19F-NMR, and Mass) as well as analytical analysis.

A facile one-pot, three-component protocol for the synthesis of novel spiro[3H-indole-3,2′-thiazolidine]-2,4′(1H)-diones by condensing 1H-indole-2,3-diones, 4H-1,2,4-triazol-4-amine and 2-sulfanylpropanoic acid in [bmim]PF6 (1-butyl-3-methyl-1H-imidazolium hexafluorophosphate) as a recyclable ionic-liquid solvent gave good to excellent yields in the absence of any catalyst (Scheme 1 and Table 2). The advantages of this protocol over conventional methods are the mild reaction conditions, the high product yields, a shorter reaction time, as well as the eco-friendly conditions.

The reactions of 3-aroylmethylene-indol-2-ones with 2-hydrazinobenzothiazole in different media and solvent were investigated. The impact of substitution on indolyl nitrogen was also studied. The chemical structure of the products was proven on the basis of their spectral (IR, 1H-NMR, 13C-NMR, Mass) and analytical studies.

(Received 9 April, revised 29 July 2012) Abstract: An efficient and mild method for the synthesis of some novel 7-(1H- -benzimidazol-2-ylazo)-1,3-dimethyl-6,8-disubstituted-1H-pyrimido(4,5-b)- (1,4)diazepine-2,4-diones in water has been developed. This method is a good option to obtain the title compounds in quantitative yields in a simple and inexpensive manner. Further, the NH of the title compounds was replaced by various substituents in an ionic liquid, (bmim)PF6, a recyclable and environ- mentally benign solvent. The synthesized compounds were characterized by analytical and spectral (IR, 1 H-NMR, 13 C-NMR and FAB mass) data and have been screened for their anti-anxiety activity in mice.

Studies on the title reaction in different media indicate that ionic liquid [bmim]PF6 is a good solvent to achieve spiro[indole-pyrazole] (III) in excellent yield.

A facile one-pot, three-component protocol for the synthesis of novel spiro[3H-indole-3,2′-thiazolidine]-2,4′(1H)-diones by condensing 1H-indole-2,3-diones, 4H-1,2,4-triazol-4-amine and 2-sulfanylpropanoic acid in [bmim]PF6 (1-butyl-3-methyl-1H-imidazolium hexafluorophosphate) as a recyclable ionic-liquid solvent gave good to excellent yields in the absence of any catalyst (Scheme 1 and Table 2). The advantages of this protocol over conventional methods are the mild reaction conditions, the high product yields, a shorter reaction time, as well as the eco-friendly conditions.