Application of Lohr

• Decision Date: 16 May 1963
• Docket Number: Patent Appeal No. 6968.
• Citation: 50 CCPA 1274,317 F.2d 388
• Parties: Application of Arthur D. LOHR and Harold M. Spurlin.
• Court: U.S. Court of Customs and Patent Appeals (CCPA)

50 CCPA 1274, 317 F.2d 388 (1963)

Application of Arthur D. LOHR and Harold M. Spurlin.

Patent Appeal No. 6968.

United States Court of Customs and Patent Appeals.

May 16, 1963.

Clinton F. Miller, Wilmington, Del. (S. Grant Stewart, Wilmington, Del., of counsel), for appellants.

Clarence W. Moore, Washington, D. C. (Raymond E. Martin, Washington, D. C., of counsel), for the Commissioner of Patents.

Before WORLEY, Chief Judge, and RICH, MARTIN, SMITH, and ALMOND, Judges.

ALMOND, Judge.

This is an appeal from the decision of the Patent Office Board of Appeals affirming the examiner's rejection of claims 1 to 10, the only claims of appellants' patent application,¹ as unpatentable over a single prior art patent.

The invention relates to organic thiophosphate compounds having the general formula

in which R represents a lower alkyl radical.

The compounds have pesticidal properties and are said to distinguish over known pesticidal compounds in being more toxic at low concentrations toward certain pests and in having exceptionally good systemic toxicity.

The claims are drawn to the new compounds alone and to pesticidal compositions comprising the compounds and "an insecticidal adjuvant." Claim 1 is a representative compound claim and reads:

"1. As a new composition of matter a compound of the formula

in which each R represents a radical of the group consisting of lower alkyl and chloro lower alkyl."

The reference relied on is:

Haubein 2,725,331 November 29, 1955.

The claimed compounds are homologs² of the compounds shown in the Haubein reference with the sole difference being the presence in the claimed compounds of two methyl groups at the 2 and 6 positions of the heterocyclic nucleus. Haubein discloses 2,3-thioxanedithiol S,S-Bis(O,O-dialkylphosphorodithioate) without the dimethyl substitution on the ring. Use as a pesticide and dilution with an insecticidal adjuvant as a carrier are also taught in Haubein. The compounds are made by the same reactions in Haubein as are disclosed in the instant specification, viz., a parathioxane derivative is reacted with the diester of dithiophosphoric acid.

Appellants admit "a superficial resemblance" to the Haubein esters, but contend that they have proceeded in a direction contrary to that suggested by the prior art and have obtained unexpected superiority in their compounds as pesticidal agents against certain insects. The argument rests on the basic premise stated in appellants' specification that "it is known that these compounds of Haubein decrease in insecticidal activity with increase in the number of carbon atoms in the molecule." The support for this premise is the teaching in the patent that pea aphids, when sprayed with a 0.05% emulsion of the ethyl ester, suffered only a 20% kill, whereas a 90% kill resulted when the methyl ester was used at half the concentration (0.025%). It should be noted, however, that the patent does not set forth the basic premise of appellants, but merely gives the two examples from which the premise was hypothesized. After assuming a relationship between the length of the alkyl chain and toxicity based on the two examples with pea aphids, it appears that appellants reasoned that the proportion of sulfur and phosphorus bears a relationship to toxicity. The final step in developing the hypothesis is that as carbon content of a molecule increases, toxicity decreases. The specification states:

"* * * Since the present compounds are higher homologs of the compounds of U.S. 2,725,331 Haubein, they contain more carbon and consequently a lower percentage of sulfur and phosphorus, and it was, therefore, surprising that their toxicity was not lower but on the contrary was much higher."

In other words, having developed this hypothesis based on the two pea aphid examples of Haubein, appellants seek a patent for having substituted methyl groups for two hydrogens on the thioxane ring, which is distinct from the portion of the compound to which the alkyl side chains are attached, in the face of the "teaching" of the prior art. They expected, having been through the above reasoning process, that adding carbon to the thioxane ring in the Haubein compounds would decrease toxicity because a greater kill of pea aphids resulted when the methyl ester was used than when the ethyl ester was used.

The examiner was not convinced that the compounds or compositions were patentable on the basis of the specification alone. He stated:

"* * * The oath does not verify the subject matter of the specification. Therefore, in the absence of a verified showing of a difference in the properties with regard to a spectrum of insects the subject matter is not patentable."

After final rejection by the primary examiner, appellants submitted two affidavits. The first was very brief and contained no factual data but merely conclusions. The second affidavit is far more complete than the first and makes a direct comparison between the compounds of Haubein and the claimed compounds in effectiveness against several pests.

The second affidavit was prepared by Haubein, the inventor of the prior art patent. He stated that he prepared the insecticides and turned them over to trained entomologists for comparative toxicity studies by standard test procedures. The tabulated results compared the effectiveness of the methyl, ethyl and propyl esters of the Haubein general formula and of appellants' general formula with respect to houseflies, Mexican bean beetles and two-spotted spider mites.

The second affidavit is relied on to support the theory that increasing the number of carbon atoms in the alkyl group of the ester side chains will decrease toxicity as well as to prove the unexpected superiority of the dimethyl substituted compounds of the instant claims.

As to the first proposition, appellants argue that the Board of Appeals did not challenge appellants' position that there is a detrimental influence in...