Application of Cescon, Patent Appeal No. 8884.

• Decision Date: 22 March 1973
• Docket Number: Patent Appeal No. 8884.
• Parties: Application of Lawrence Anthony CESCON.
• Court: U.S. Court of Customs and Patent Appeals (CCPA)

177 USPQ 264, 474 F.2d 1331 (1973)

Application of Lawrence Anthony CESCON.

Patent Appeal No. 8884.

United States Court of Customs and Patent Appeals.

March 22, 1973.

William R. Moser, James T. Corle, Wilmington, Del., attorneys of record, for appellants; Gerald A. Hapka, Washington, D. C., of counsel.

S. Wm. Cochran, Washington, D. C., for the Commissioner of Patents; Jack E. Armore, Washington, D. C., of counsel.

Before MARKEY, Chief Judge, and RICH, ALMOND, BALDWIN, and LANE, Judges.

MARKEY, Chief Judge.

This appeal is from the decision of the Board of Appeals sustaining rejections of claims 1, 2, 4, 5 and 11 under 35 U.S.C. § 103 and claims 1, 41-44 and 51 under 35 U.S.C. § 112 of appellant's application serial No. 622,085, filed March 10, 1967, for "Phototropic 2, 4, 5-Triphenylimidazolyl Radicals and Dimers Thereof."¹ We reverse.

The Invention

The invention relates to novel photodissociable, substantially colorless imidazolyl dimers and colored radicals formed therefrom under light stimulation. Claim 1 is illustrative:

1. A composition of matter selected from the class consisting of

A. A light-stable imidazolyl maintained under the influence of ultraviolet light represented by the formula

wherein R1 has a sigma value below 0.7 and is selected from lower alkyl, lower alkoxy, lower alkoxycarbonyl, lower alkylthio, di(lower alkyl)-carbamoyl, di-(lower alkyl) sulfamoyl, lower alkanoyloxy, N-lower alkyl-lower alkanamido, phenyl, naphthyl, phenyloxy, naphthyloxy, phenylthio, naphthylthio, halo or cyano;

R2 through R10 are each individually selected from hydrogen, lower alkyl, lower alkoxy, lower alkoxycarbonyl, lower alkylthio, di(lower alkyl) carbamoyl, di(lower alkyl)sulfamoyl, lower alkanoyloxy, N-lower alkyl-lower alkanamido, phenyl, naphthyl, phenyloxy, naphthyloxy, phenylthio, naphthylthio, halo or cyano;

and any two R1 through R10 substituents in adjacent positions on the same phenyl ring of the above formula can be joined together to form a -CH=CH- group; and

with the proviso that only one of R5 through R7 and only one of R8 through R10 can be in a position ortho to the phenyl carbon that is attached to the imidazolyl nucleus of the above formula;

said imidazolyl having an unpaired delocalized electron and having four electrons paired; and

said imidazolyl being maintained upon the surface of an inert substrate or in solution in a solvent that is inert to said imidazolyl; and

B. dimers thereof, said dimers having the property of forming color in solution in an inert solvent upon exposure to ultraviolet radiation corresponding to the ultraviolet light absorption spectrum of the dimer, which color fades upon removal of the radiation.

Claims 2, 4, 5 and 11 are restricted to compositions consisting essentially of the imidazolyl form and substrate or solvent (A in claim 1), varying in scope as to substitutents R1 through R10. Claims 41-44 are drawn to the dimer form, without specification as to linkage, varying in scope as to R substituents. In claim 51 the general imidazolyl radical formula of claim 1 is set forth as being in reversible equilibrium with the dimer in an inert solvent.

The phototropic nature of the compositions, i. e. their change in color upon exposure to light and reversal upon removal of the stimulus, renders them useful as automatic sun shades. The phenomenon of phototropism itself is not unexpected. Appellant's contribution lies instead in the discovery that the presence of an ortho substituent in the 2-phenyl ring imparts an improved responsiveness to changes in light intensity. Greatly increased color fading rates are obtained. Furthermore, such a substituent raises the temperature required to dissociate the dimer, reducing unwanted color due to thermal dissociation in the dark. Other distinguishing properties are increased stability and a higher number of color reversals before composition failure.

The 103 Rejection

The references relied upon by the examiner and the board were:

                  Green              U.S. 3,205,083      Sept. 7, 1965
                  Neugebauer et al.  German Patent       May 10, 1961
                                     1,106,599
                  Deliwala et al.    Chem. Abstracts, volume 45, cols
                                     6177-78 (1951)
                  Radziszewski       Chem. Abstracts, volume 4, pages
                                     2265-66 (1910)
                  Hayashi et al.     Bull. Chem. Soc. (Japan) volume
                                     33, pages 564-66 (1960)
                  Zimmerman et al.   Angew. Chem., volume 73, page
                                     808 (1961)
                  Gould              Mechanism and Structure in Organic
                                     Chemistry, pages 672-82
                                     New York, Holt (1959)
                

Green, Neugebauer, Deliwala and Radziszewski (the primary references) disclose several substituted 2, 4, 5-triphenylimidazoles wherein there is an ortho substituent of the type encompassed by R1 of the claims in the 2-phenyl ring. Hayashi and Zimmerman teach two different methods for obtaining the free radical form from unsubstituted 2, 4, 5-triphenylimidazole or triphenylimidazoles having para-methyl or methoxy substituents on the 2-phenyl ring. Gould merely provides background information on free radicals, having no specific disclosure directed to imidazoles.

Claims 1, 2, 4, 5 and 11 were rejected under 35 U.S.C. § 103 as unpatentable over the cited references. It was the examiner's position that the claimed imidazolyl radicals were obvious in view of the precursor imidazoles disclosed by the primary references considering the known methods of Hayashi and Zimmerman for preparing related imidazolyl free radicals from such an imidazole form. Since the prior art imidazoles relied upon had ortho substitution in the 2-phenyl ring, the examiner considered any differences of the claimed imidazolyl radicals resulting from such substitution to be irrelevant to the issue involved herein.

In sustaining the rejection, the board added that in view of the known methods of preparation and the availability of the precursors of appellant's claimed compounds, "unobviousness cannot be predicated merely on an emphasis on compounds with a particular locus of substitution." While the showings of improved properties alleged to be dependent on ortho substitution were not totally disregarded, as was the case with the examiner, the board found the same to be inadequate, holding:

* * * Appellant\'s argument or implication that the claimed free radicals necessarily must have "beneficial" properties not possessed by

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