A green tactic for the synthesis of classical 3,3-bisindolylmethanes in waste curd water

The biowaste curd water generated after the curd formation was utilized as an acid catalytic green solvent for the synthesis of 3,3-bisindolylmethanes derivatives. The soluble organic acid (i.e. lactic acid) responsible for the acidity to curd water which adequately fulfills the purpose of acid catalyzed reaction, where 2 mol of indole reacted with an aldehyde in the presence of curd water at a low temperature and yields classical 3,3-bisindolylmethanes derivatives. During the reaction, continuous product formation and isolation was observed. The product precipitate was separated by the successive method of filtration. This biowaste water catalyzed method is highly retrievable and advantageous over the trend of high-temperature inorganic acid catalyzed reaction offering the effortlessly separable product.