3 12 9 and varying, but small amounts of the P-oxo hydroxamic acid 10. During the column chromatographic (CC) separation procedures using silica gel a new compound was formed in varying quantities depending on the duration of the CC procedures. This latter compound, which could also be made by treatment of 8 with silica gel and the particular CC eluent, was shown to be the 2-isoxazolin-5-one tautomer (11) of 8. This structure assignment is in ...
