Synthesis of New Pyrrole Alcohols Using Sodium Borohydride Reduction in Small Amount of PEG under Grinding Conditions

In the report, ten pyrrole aldehydes were prepared from β-keto acid esters by nitrosation, Knorr condensation and oxidation with ammonium ceric nitrate. Then, in the medium of micro PEG-600, the pyrrole aldehydes and sodium borohydride were grinded into the shape of dough using an agate mortar and pestle and then kept at room temperature. The corresponding alcohols were obtained. All the compounds were characterized and determined by IR, 1H NMR, and ESI MS. Among them, 5 pyrrole aldehydes (2c, 2f, 2h~2j) and 8 pyrrole alcohols (3a~3d, 3f, 3h~3j) are new compounds. This synthesis method for the reduction of pyrrole aldehydes with NaBH4 has the advantage of simple operation, low energy consumption, high yield and environmental friendly.