Appeal No. 2004-0245
Application 09/265,926
The coupling and decarboxylation sequence of sequence “(i)” is shown in the first
equation in “scheme 2” (specification, page 6) wherein the 6-chloro-purine derivative
intermediate depicted is encompassed by appealed product claim 5, a synthesis of which is set
forth in specification Example 1. The synthesis set forth in specification Example 1 includes the
step of decarboxylation of the tri carboxylate moiety of the 6-chloro-purine derivative
intermediate, obtained by coupling the starting material triethyl 3-bromopropane-
1,1,1-tricarboxylate, with “a solution of sodium methoxide . . . in methanol,” which includes the
transesterification of ethyl-carboxylate groups to the corresponding methyl carboxylate groups in
that position, as depicted in “scheme 2.”2
In appealed claim 10, the sequence “(ii)” of converting a 6-chloro-purine derivative
intermediate of formula (I) to the final product of structural formula (A) includes, inter alia,
reducing the carboxylate ester groups to hydroxy groups that are then acetylated to result in a
6-chloro-purine derivative intermediate containing acetoxymethyl groups in the “9” position
encompassed by formula (I).3
The reduction and acetylation sequence is shown in the second equation in “scheme 2,”
and a process of preparing the intermediate is exemplified in specification Example 2 which
starts with the intermediate product prepared in specification Example 1.
Sequence “(ii)” concludes with the dechlorination of the 6-chloro-purine intermediate of
the previous sequence by, inter alia, a hydrogenolysis reaction which results in a 6-hydrogen-
purine derivative product that falls within formula (A) in appealed claim 10.
The hydrogenolysis reaction is shown in the last equation in “scheme 2,” and a process of
preparing the 6-hydrogen-purine derivative product so obtained is exemplified in specification
Example 3, which starts with the intermediate product prepared in specification Example 2.
In comparison with appealed claim 10, we find that Grinter would have disclosed to one
of ordinary skill in this art the preparation of purine derivatives of formula (A) thereof (e.g.,
According to USPTO records, Novartis International Pharma, Ltd., is the common assignee of
the present application and the ‘288 patent (see brief, page 1).
2 Compare the ethyl carboxylate group “-CO2ET” of the triethyl 3-bromopropane-
1,1,1-tricarboxylate starting material with the methyl carboxylate group “-CO2Me” of 6-chloro-
purine intermediate in “scheme 2.”
3 The “-OAc” group can be depicted as “-O-CO-CH3.”
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