Spirooxindole-pyrazolines

Keywords Isatin, hydrazine hydrate, l,l-bis(methylthio)-2-nitroethylene, ethanol, room temperature, one-pot multicomponent reaction, spirooxindole-pyrazolines... 

To a solution of l,l-bis(thiomethyl)-2-nitroethylene (2 1 mmol) in ethanol (4 mL) in a 10 mL flask was added NH2NH2 H2O (3 80% aq., 2 mmol) and stirred for 5 h at room temperature. After then, isatin (1 2 mmol) was added to the reaction mixture, and stirring was continued for another 3-7 h. On completion of the reaction, the crude precipitated was filtered and washed with cold ethanol to obtain piu-e product of spirooxindole-pyrazoline 4. All the products were characterized by spectral studies. 

Alizadeh, A., and Zohreh, N. (2012). A unique approach to catalyst-free, one-pot s5Tithesis of spirooxindole-pyrazolines. Synlett, 23, 428-432. 

Dandia et al. [129] have developed an efficient and novel green catalytic protocol for the synthesis of biologically important spirooxindole derivatives (196) in a one-pot, three-component approach involving substituted isatin (193), activated methylene reagent (194), and 3-methyl-l-phenyl-2-pyrazolin-5-one (195) in water, xmder sonication. The report describes the use of sodium chloride as a nonacidic catalyst in aqueous media. The desired compoxmds were obtained in excellent yield (purity not less than 95%) without using complex catalysts and organic solvents, and without additional purification (Scheme 51). 

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