MacGregor specifically discloses that the organic thioether reactant (which forms the R — S — R' portion of the prior art class of compounds) is “preferably” one of “those containing up to 20 carbon atoms and having at least one methylene group attached to the sulfur atom,” and illustrates the preferred alkyls with, inter alia, methyl and dodecyl. Usefulness of the compounds as biological toxicants is shown.
Cisney, assigned to the same assignee as MacGregor, discloses a class of hydroxyaryl sulfonium chloride compounds made by a process improved over that of MacGregor and having the same uses shown by MacGregor. It has substantially the same disclosure as MacGregor with respect to the described class of sulfonium chlorides, the only difference being that Cisney defines the R and R' radicals as selected from alkyl of 1 — 20 carbon atoms, 2-chloroethyl, aryl, arylalkyl of 7 — 8 carbon atoms, and alkylaryl of 7-10 carbon atoms. This is a narrower group than that defined by MacGregor. The improved process (which reduces formation of by-products) reacts a thioether with chlorine to form a first reaction product and then reacts this product with a phenol to produce the sulfonium chloride, in the following manner:
[figure]
Rebuttal Evidence
Appellants have relied on data in their specification and on an affidavit of Lamberti to show unobviousness. The specification states that the compounds in the claimed class contain unexpectedly good germicidal activity, especially against gram positive bacteria. It sets forth examples and comparative data which allegedly show that the minimum effective concentration for germicidal activity of the claimed compounds was unexpectedly lower than for the other compounds tested.
The affidavit of Lamberti allegedly shows the inoperability of the process of producing specific hydroxyaryl dioctyl sulfonium chlorides (Example 9 of MacGregor and Example 5 of Cisney). The affidavit, in pertinent part, states:
• I have attempted to duplicate certain of the examples described in the above-identified applications of Cisney and MacGregor and to that end I directed persons working under my direction to prepare dioctyl sulfonium compounds according to Example 5 of Cisney and Example 9 of MacGregor. Five separate attempts to produce the dioctyl compound according to the referenced patents were made by three different chemists, and each such attempt was unsuccessful.
• Based upon the five attempts by three different chemists acting under my supervision, I have concluded that the Cisney and MacGregor references do not teach the preparation of the dioctyl compounds which the patents purport to disclose.
The affidavit includes an exhibit showing the unsuccessful attempts to prepare the compounds according to Example 9 of MacGregor, but it does not contain the facts upon which the stated inoperability of Example 5 of Cisney was based.
Proceedings Below
The examiner rejected the claims, inter alia, under 35 U.S.C. 103 as obvious in view of either MacGregor or Cisney.
The board affirmed only the 35 U.S.C. § 103 rejection, holding that it would have been obvious to use an asymmetric dialkyl thioether in the disclosed process of MacGregor or Cisney to produce a hydroxyphenyl dialkyl sulfonium halide having an asymmetric dialkyl grouping. The board noted that “[e]ach of MacGregor and Cisney teach [sic] hydroxy phenyl dialkylsulfonium halides useful as biological toxicants which necessarily includes bactericides.”
The board also held that the rebuttal evidence did not overcome the prima facie