1,3,5-Tris(hydrogensulfato) Benzene: A New and Efficient Catalyst for Synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ol) Derivatives

1,3,5-Tris(hydrogensulfato) benzene (THSB) was easily prepared by the reaction between phloroglucinol and chlorosulfonic acid in dichloromethane at room temperature. This compound was then used as an efficient catalyst for the synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols) through the condensation reactions of 1-phenyl-3-methylpyrazol-5-one with several different aromatic aldehydes in ethanol at 75 °C. The present methodology offers several advantages over existing methodologies, such as excellent yields, simple procedure, easy work-up and ecofriendly reaction conditions.

Graphical abstract1,3,5-Tris(hydrogensulfato) benzene has been used as an new and efficient catalyst for the one-pot synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols) through the condensation reactions of 1-phenyl-3-methylpyrazol-5-one with a variety of different aromatic aldehydes in ethanol at 75 °C.Figure optionsDownload full-size imageDownload as PowerPoint slide