NoteStrueture of Precarthamin , a BiosyntheticPrecursor of Carthamin

present in them. In 1953, the presence ofa precursor was proved by one of the authors (M.W,)3) and it has been called precarthamin,`} a yellow unstable substance which was changed into carthamin by oxidation with permanganate or by autoxidation with oxygen in air or in a solution. The structure has only recently been revealed because of the compound's instability,S・6) the structural deterrnination bei g independently accomplished by us and by J. Onodera et aL 7'8) Wc now report a new isolation method