Interference No. 103,675
Thus, Chen et al. represented that they discovered that what was
prepared was not a mixture of fluoro epimers of taxol but a mixture of
a 7-"-fluoro taxol derivative and a 7,8-cyclopropyl taxol derivative.
In the compound submission form for BMS-183821-01 the amount
of sample submitted as completed by Dr. Chen is "10.2 mg" yet the
amount of product obtained on Dr. Chen's notebook for 32044-39 is set
forth as "9 mg of pdt was isolated 84.2% yield." It is not apparent to
this Board how the additional sample was obtained.
We have no doubt from all the above-noted evidence that Dr.
Chen was actively engaged in synthesizing derivatives of taxol in the
critical time period. The problem with Chen et al.'s proofs, however,
is one of identification of exactly what was prepared. Compounding
this problem is the absence of adequate evidence establishing how Dr.
Chen and the other researchers separated the compounds allegedly
produced and subsequently tested the compounds for structural
determination and utility. Certainly, thin layer chromatography (TLC),
the procedure Dr. Chen represents to have used to perform a gross
separation of "product" from the starting materials, does not permit
the researcher to accumulate the sample which has been separated and
recover and identify the same without the use of other analytical
methods14. Rather, TLC is a useful tool for indicating whether or not a
14 We take official notice of the fact that TLC is a
chromatographic technique useful for separating organic compounds
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