Waste Waters of Milk and Cheese Processing as an Efficient Promoter for the Synthesis of 1,8-dioxo-octahydroxanthones

Waste waters of agricultural and industrial processing have been recently employed to effectively promote numerous “classic” and innovative processes of synthetic organic chemistry. Such a green chemical approach allowed to bypass the use of toxic, polluting, and hazardous chemicals and in the meantime led to an increase of the commercial values of such byproducts. Xanthenes are a group of natural and semi-synthetic compounds with great pharmacological potentialities, also used for several other applications. In this paper we described a new and improved methodology for the synthesis of the title compounds using waste waters of milk and cheese processing as a solvent. 1,8-Dioxo-octahydroxanthenes were obtained in very good yields (94 – 98 %) from differently substituted aromatic aldehydes and dimedone as substrates. Although several reports about the synthesis of 1,8-dioxo-octahydroxanthenes have been published in recent years, this is the first report about the use of waste waters of agricultural and industrial processing to this aim. The findings depicted herein underline once again the great usefulness of agricultural and food industry byproducts to perform green chemical processes.