A New and Expedient Total Synthesis of Ochratoxin A and d(5)-Ochratoxin A

A new total synthesis of the mycotoxin ochratoxin A (OTA) is presented (9% overall yield from commercially available substrates). The key step consists in the condensation reaction between protected L-phenylalanine and 5-chloro-8-hydroxy-3-methyl-1-oxoisochroman-7-carboxylic acid, known as ochratoxin alpha (OTalpha). Using d5-L-phenylalanine, the same strategy could be successfully applied to the first total synthesis of d5-OTA, a molecular tracer for the detection and analytic quantification of the natural mycotoxin in food samples by means of SIDA (stable isotope dilution assay).

A new total synthesis of the mycotoxin ochratoxin A (OTA) is presented, in which it is prepared in 9% overall yield from commercially available Substrates. The key step consists of the condensation reaction between protected L-phenylalanine and 5-chloro-8-hydroxy-3-methyl-1-oxoisochromane-7-carboxylic acid (ochratoxin alpha, OT alpha). The same strategy could be successfully applied to L-d(5)-phenylalanine, leading to the first total synthesis of d(5)-OTA a molecular tracer (or the detection and analytical quantification of the natural mycotoxin in food samples by means of stable isotope dilution assay (SIDA). RI Di Donna, Leonardo/D-5707-2011