Appeal No. 2001-1218 Page 5
Application No. 08/727,798
limitation argued by appellants in the statement of the rejection. In the response
to arguments, however, the examiner argues that the Cl-Z protecting group used
by Folkers is considered to be a base labile protecting group. The examiner
rests this assertion on page 24, lines 30-32 of the instant specification, wherein
Xa is designated as subgroup of the broader carbonyl containing group, X6.
Appellants state at pages 24-25 of the specification that:
X6 is a protecting group for an amino side chain group, primary or
secondary amino, such as Z or 2ClZ; Xa is a subclass of X6
comprising such protecting groups that can be removed without
removing other side chain protecting groups so as to allow the
omega-amino group to thereafter take part in the reactions to build
the unnatural amino acid residue. Preferably a base-labile group,
such as Fmoc, methylsulfonylethoxycarbonyl (Msc) or
trifluoroacetyl (Tfa), is used; however it may also be possible to use
a hydrazine-labile group such as phthaloyl, [chemical structure] or a
thiolabile group such as NPS or Dts.
The above passage, while noting that the Xa group may be a subgroup of
the broader group X6, which includes the ClZ protecting group, does not teach
that the ClZ protecting group is a base-labile protecting group. Further, Folkers
does use the Cl-Z group as an amino protecting group, see col. 3, lines 63-65,
but the peptides were cleaved from the resin and deprotected using HF, a strong
acid, see col. 8, lines 60-68. There is no discussion in Folkers that the ClZ
protecting group is removed by means other than HF treatment. Therefore, the
examiner has not met her burden of establishing that the 5 and 6 positions of the
peptides disclosed by Folkers contain side chains having primary amino groups
that are modified with a base-labile, a hydrazine-labile or a thio-labile protecting
group, and the rejection is reversed.
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