9-hydroxy-2-mercapto-6-phenyl-2-thioxo-1,3,5-trioxa-2lambda(5)-phospha-cyclopenta(b)naphthalen-8-one
9-hydroxy-2-mercapto-6-phenyl-2-thioxo-1,3,5-trioxa-2lambda(5)-phospha-cyclopenta(b)naphthalen-8-one