Court Opinion

ID: 8907575
Source: CourtListenerOpinion
Date Created: 2022-11-27 02:03:50.869408+00
Date Added: 2024-06-11T17:08:18.868072
License: Public Domain

MILLER, Judge,
dissenting.
I cannot agree with the conclusion in the majority opinion that one skilled in the art would have had a “presumed expectation” that the claimed compounds would possess properties similar to those of Mitsuda compound III.
The Mitsuda reference1 discloses three compounds:2
*643I

II

III [cited by the Patent and Trademark Office ("PTO")]

The generic class of compounds claimed may be represented as follows, with R1 and R2 being the same or different and each being lower alkyl:3
OH CHO R1 R2
The Mitsuda reference reports that compounds I and III inhibit the growth of E. coli and that compound II (which does not have the two hydrogen substituents at the 7-position) does not. Thus, the reference upon which the PTO relies to establish its prima facie case teaches that changes in the number and/or type of substituents at the 7-position of these pteridine compounds can have a dramatic effect upon their antimicrobial activity. It follows that, with only the three compounds of the Mitsuda reference before him, one skilled in the art would not have had a “presumed expectation” that the claimed compounds, which substitute lower alkyl groups (e. g., methyl (-CH 3) or ethyl (-C 2H 5) groups) for both available hydrogens at the 7-position, would exhibit antimicrobial activity.4 At most, he would have had a presumed hope that the claimed compounds would have the antimicrobial activity.
The majority opinion dismisses the significance of the Mitsuda teaching by noting that compounds I and III differ in the substituent at the 6-position. However, no reason is given (nor would it appear to have been readily apparent to one skilled in the art) for expecting that the substitution of a carbonyl (-CHO) group for a carboxyl (-CO 2H) group would have any effect upon antimicrobial activity. Indeed, the Mitsuda reference suggests that there would be no effect, since compounds I and III differ *644only in the substituent at the 6-position; yet both have antimicrobial activity. On the other hand, since it appears that the difference in the substituents at the 7-posi-tion of Mitsuda’s compound II is the reason for no antimicrobial activity, one skilled in the art would have expected that a difference in the substituents at the 7-position of the claimed compounds would affect the antimicrobial activity.
Thus, the teachings of the Mitsuda reference do not establish a prima facie case of obviousness. This conclusion is reinforced by the treatise on heterocyclic compounds.5 This treatise teaches that compounds such as Mitsuda’s compounds I and III “are extremely susceptible” to the elementary chemical reaction of dehydrogenation at the 7-8 positions; whereas, Mitsuda compound II and the claimed compounds cannot undergo dehydrogenation due to the number and type of substituents at the 7-position. With this additional teaching, one skilled in the art would have had no reason for predicting the properties of the compound appellant is claiming.
In view of the foregoing, I would, without reaching the issue of the potentiating effect of the claimed compounds, reverse the decision of the board.

. Mitsuda & Suzuki, Effects of 2-amino-4-hy-droxy-6-carboxy-7,8-dihydropteridine and 2-amino-4-bydroxy-6-formyI-7,8-dihydropteridine on the growth of Escherichia coli, 75 Chemical Abstracts 72963n (1971).

. For clarity, all compounds have been depicted in the tautomeric form with a hydroxyl (-OH) group at the 4-position. See note 6 of the majority opinion and the accompanying text.

. The appealed claims are reproduced in the majority opinion.

. Although appellants have not argued specifically the import of Mitsuda compounds I and II, they have argued that the Mitsuda reference is insufficient to make out a prima facie case, because the reference does not demonstrate that the gem dialkyl structure (substitution of lower alkyl groups for both available hydro-gens at the 7-position) is well known in the art for its antimicrobial activity. Cf. In re Mercier, 515 F.2d 1161, 185 USPQ 774 (Cust. & Pat.App. 1975). Moreover, citing the treatise on hetero-cyclic compounds (infra note 5), appellants have argued that the substituents at the 7-posi-tion prevent the claimed compounds, like Mitsuda compound II, from undergoing dehydrogenation; whereas, the Mitsuda compound III undergoes dehydrogenation.

. 9 HETEROCYCLIC COMPOUNDS: Pteridines, Alloxazines and Compounds with 7-Membered or Larger Rings 38-39 (R. Elderfield ed. 1967).