Application of Coker

• Decision Date: 17 August 1972
• Docket Number: Patent Appeal No. 8674.
• Citation: 175 USPQ 26,463 F.2d 1344
• Parties: Application of William P. COKER et al.
• Court: U.S. Court of Customs and Patent Appeals (CCPA)

175 USPQ 26, 463 F.2d 1344 (1972)

Application of William P. COKER et al.

Patent Appeal No. 8674.

United States Court of Customs and Patent Appeals.

August 17, 1972.

Bernd W. Sandt, Midland, Mich., Arthur R. Whale, Kalamazoo, Mich., attorneys of record, for appellant.

S. Wm. Cochran, Washington, D. C., for the Commissioner of Patents. Fred E. McKelvey, Washington, D. C., of counsel.

Before RICH, Acting Chief Judge, ALMOND, BALDWIN and LANE, Judges, and ROSENSTEIN, Judge, United States Customs Court, sitting by designation.

BALDWIN, Judge.

This appeal is from the decision of the Patent Office Board of Appeals, adhered to on reconsideration, sustaining the rejection of claims 1-3 of appellants' application¹ under 35 U.S.C. § 102(a). Appeal of the board's decision as to two other claims has been abandoned by appellants.

The Invention

The claims are drawn to (1-aziridinyl) alkyl esters of polycarboxylic acids, which appellants disclose as being useful as inhibitors which retard the reaction of aluminum with various degreasing solvents, and as curing agents for acid terminated polymers. Appellants' compounds are prepared by a transesterification reaction between a polycarboxylic acid ester and a (1-aziridinyl) alcohol in the presence of an alkali metal alkoxide catalyst. The reaction conditions are listed in appellants' specification as generally being a pressure range of from about 50 mm. Hg to atmospheric pressure; a temperature range of from about 25° to 110°C; and, preferably, an excess of the aziridinyl alcohol. As appellants point out in their brief, the following reaction between dimethyl succinate (II) and (1-aziridinyl) ethanol (III) to form di2-(1-aziridinyl ethyl succinate (IV) and methanol (V), is illustrative:

The byproduct methanol is preferably distilled out of the reaction mixture as it is formed, in order to drive the reaction to completion. The preferred catalysts are those in which the alkoxide radical is derived from the same aziridinyl alcohol as is reacted with the polycarboxylic acid ester.

Claim 1 reads:

A compound of the formula

wherein:

(a) n is an integer from 2 to 4,

(b) A is a hydrocarbyl group of from 2 to 10 carbon atoms of valence n, and

(c) each Ro is, independently, hydrogen or a lower alkyl group.

Claim 2 recites that n is 2, and claim 3 recites that A is an alkylene or arylene group.

The Rejection

The appealed claims stand rejected under 35 U.S.C. § 102(a) as anticipated by a Tsou et al (Tsou) reference.² Tsou prepared a large number of aziridine (also called ethylenamine) derivatives and evaluated many of them as possible cancer chemotherapeutic agents. Tsou apparently theorized that the aziridinyl derivatives might be useful as chemotherapeutic agents on the basis of a "known difference in esterase activity in normal and neoplastic tissues." After discussing the preparation of a number of aziridine derivatives, the reference states:

Another type sic. Other types? of bifunctional ethylenimine compounds that can be hydrolyzed by the esterase are dibasic acid esters of (1-aziridinyl) methanol * * * and ß-(1-aziridinyl) ethanol * * *. Only the lower members of the aliphatic dicarboxylic acids are of interest because it is generally accepted that separation of the two alkylating groups over too long a chain is undesirable * * * * * * Because of the instability of the (1-aziridinyl) methanol, only (1-aziridinal) ethanol was used. Model compounds such as ß-(1-aziridinyl) ethyl acetate * * *, propionate * * *, and butyrate * * * were prepared. However, the preparation of the malonate and succinate esters has not been successful. Emphasis ours.

Both parties agree that the above language identifies di2-(1-aziridinyl) ethyl succinate, which compound is within the scope of all of the claims presently on appeal.

Tsou prepared the acetate, propionate and butyrate "model" compounds via a transesterification reaction between ß-(1-aziridinyl) ethanol and ethyl acetate, methyl propionate and methyl n-butyrate, respectively. The reactants were mixed with sodium methoxide and heated at 80-90°C. The alcohols resulting from the transesterification were removed by distillation.

The examiner noted that Tsou's method of making the model compounds (which the examiner termed "alcoholysis") corresponds to the process described in appellants' specification for making the claimed compounds. The examiner considered that, in spite of Tsou's reported lack of success in making the succinate ester, the mere naming of the compound would suggest several ways of making it, including transesterification, to one of ordinary skill in the art.

The board agreed with the examiner. It considered that Tsou's teaching of the desirability of producing the aziridine derivative as possible cancer chemotherapeutics provided a "reason for making" the compounds therein described. With regard to Tsou's unsuccessful attempt to prepare the malonate and succinate esters the board stated:

* * * We believe it to be apparent that the unsuccessful process must have been that employed in making the "Model compounds," such as the acetate, propionate, and butyrate actually produced. The very term "model" suggests a pattern to be followed for other examples. * * *

The board concluded:

There can be no question that Tsou et al., although they were unsuccessful in their preparation, describe, by name, from which the organic chemist visualizes the chemical formula, the malonic and succinic acid esters of aziridinyl ethanol. The desired utility and desirability of producing such compounds is set forth. Under such conditions we agree with the Examiner that the name alone is sufficient to place in possession of the organic chemist of ordinary skill these two compounds which fully meet the terms of claims 1, 2, and 3.

Although the process employed in Tsou et al. was unsuccessful, for reasons not given, the art is well aware of numerous methods for forming comparatively simple esters of the type described in Tsou et al. In page 6 of the Examiner\'s Answer, without denial by appellants, the Examiner has indicated numerous other known methods for forming compounds of this type which would be expected to produce the desired products. It is to be noted that such processes include not only normal direct esterifications of an alcohol but also an example of the very well-known addition of ethylene imine ("aziridine") to double bonds. The application of this known reaction to divinyl succinate or malonate would be expected, as pointed out by the Examiner, to produce the compounds described by name and desired in Tsou et

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