Appeal No. 2001-0694 Page 3
Application No. 08/908,807
According to the Appeal Brief, only one of the isomers of the position 13 is
clinically interesting—the 2'R,3'S isomer. See id. Therefore, synthetic methods
have centered on synthesizing the position 13 sidechain in a stereospecific manner.
Thus, the Appeal Brief states that prior art methods focused on the use of an
oxazolidine ring to add that sidechain, wherein the ring had the same
stereochemistry as that desired in the position 13 side chain, i.e., the prior art
focused on the use of a 4S,5R oxazolidine. See id. at 3.
The specification teaches synthesis of taxane derivatives, wherein an
oxazolidine as claimed in claim 17 is used. See Specification, pages 7-8. The
claimed oxazolidine differs from the prior art in that it does not have the
stereochemistry of the side chain in the taxane derivative, i.e., the oxazolidines used
in prior art syntheses are the 4S,5R isomer, whereas the claimed oxazolidine is the
4S,5S isomer. See id. at 8. According to the specification, the desired taxane
derivatives “can be obtained, with a stereoselectivity in the region of 100%,” in a
synthetic method utilizing the claimed 4S,5S isomers. Id. at 7.
DISCUSSION
The examiner has rejected claims 17-21, i.e., all the pending claims, as
being rendered obvious by Bourzat II, Commercon III or Kelly. The claims were also
subject to a double-patenting rejection over claims 1-3 of Mas, claim 29 of
Commercon I, claims 1 and 2 of Commercon II and claim 13 of Bourzat I.
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