Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of the Claims
Per Applicant’s amendment to the claims, submitted on 05/01/2026, claims 1-5 are amended, and claims 6-7 are canceled. Currently, claims 1-5 are pending in the instant application.
Claim Rejections - 35 USC § 112 First Paragraph - Withdrawn
Rejections of claims 1-5:
In light of Applicant’s amendment to the claims, the rejections are hereby withdrawn. The claims have been amended to specify the use of silver (II) fluoride and a tetraalkylammonium halide.
Claim Rejections - 35 USC § 103 - Maintained
Claim(s) 1-5 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ou (previously referenced) in view of Williams (previously referenced).
Response to Remarks:
Applicant’s arguments are not persuasive, the rejections are hereby maintained. Firstly, Applicant contends that the substitution of the XeF2 reagent for the AgF2 reagent taught by Williams would constitute a change in the principle operation of the prior art. However, the principle operation of the teachings of Ou have not been rendered inoperable. Ou teaches a method of fluorinating aryl sulfur compounds by oxidative fluorination in order to arrive at an aryl sulfur pentafluoro compound (Eq. (2)):
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In the case of Ou, XeF2 is used as an oxidizing agent and fluorine donor to form the pentafluoro species, while Et4NCl appears to be used in order to enable a higher oxidation state for the sulfur species (i.e., sulfur (VI)), providing an environment more favorable for the formation of sulfur pentafluoro species. In Williams, AgF2 is used in the same manner as a fluoride donor for the formation of sulfur pentafluoro moieties (specification page 4)1. Even if, in one aspect, the study of Ou was conducted to demonstrate the utility of XeF2, it would have been readily recognizable to a person of ordinary skill in the art that XeF2 and AgF2 would have a degree of predictable analogous function in the context of oxidative fluorination. While Applicant may not be explicitly incorrect with regards to the intent of the study of Ou, the prior art is valuable for what it teaches as a whole, rather than just its end goal or intended purpose. Accordingly, a person of ordinary skill in the art would have a reasonable expectation that the substitution of XeF2 for AgF2 in the method of Ou would successfully be able to synthesize the target sulfur pentafluoro compounds.
Secondly, Applicant contends non-obviousness on the grounds that Williams teaches the use of solvents different from the “aprotic polar solvent” now recited in claim 1. While Applicant is not explicitly incorrect regarding the lone teachings of Williams regarding the solvent, it still remains that the rejection exists over the combination of the teachings of both Ou and Williams. Williams may teach the use of certain high boiling point hydrocarbon solvents, but Ou teaches the use of CD2Cl2 as a solvent. For example Ou provides the following exemplary preparation (page 282):
“To PhSSPh (17 mg, 0.078 mmol) in CD2Cl2 (0.3 mL) in a ptfe-lined NMR tube was added Et4NCl (2 mg, 0.012 mmol) at 258C. Solid XeF2 (82 mg, 0.48 mmol) was then added slowly to the reaction mixture and the colourless solution turned yellow, with gas evolution. After 30 min, another batch of Et4NCl (6 mg, 0.036 mmol) was added. Gas evolved vigorously and the solution turned deep yellow and back to colourless, to give PhSF5 (25%), identified by 19F NMR [3], along with some trans-PhSF4Cl.”
CD2Cl2 is considered as being an aprotic polar solvent, being a deuterated analog of dichloromethane. As iterated previously, the combined teachings of Ou and Williams provide a reasonable obvious substitution of XeF2 for AgF2, and further appear to teach each of the aspects of the instant claims.
Accordingly, the rejections of claims 1-5 are hereby maintained. The reiterated rejection will be provided below for the purpose of clarity and reference.
Reiterated Rejections:
Claim 1 recites a method for producing a pentafluorosulfanyl group-containing aryl compound represented by formula (1):
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From a thioaryl compound of formula (2):
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By oxidative fluorination reaction using a divalent or higher valent metal fluoride and an organic salt including a quaternary ammonium cation or a quaternary phosphonium ion.
Ou teaches the synthesis of aryl sulfur pentafluorides. More specifically, the formation through oxidative fluorination of phenyl sulfur pentafluoride (PhSF5) by combining phenyl disulfide, xenon disulfide, and NEt4Cl, wherein the overall reaction is provide below (page 279, (2)):
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The phenyl disulfide used by Ou is a compound of formula (2) wherein A1 is phenyl (i.e., unsubstituted aryl) and G1 is S-S-R1, wherein R1 is unsubstituted aryl. The resulting product of PhSF5 is a compound of formula (1) wherein A1 is phenyl. Furthermore, Ou uses the quaternary ammonium salt NEt4Cl. In an exemplary synthesis, PhSF5 was produced at a 25% yield (page 282)2. Ou does not explicitly teach the use of a divalent or higher valent metal fluoride. However, the use of such a metal fluoride would be obvious because Ou indicates that it is known in the art that aryl sulfide pentafluorides can be formed using AgF2, and Williams teaches the use of silver difluoride (AgF2) to convert aryl disulfides to aryl sulfur pentafluorides at greater yield.
As indicated above, Ou does not explicitly teach the use of AgF2, however they do make mention that AgF2 can be used to form aryl sulfur pentafluorides (page 279)3.
Similarly to Ou, Williams teaches a method of synthesizing aryl sulfur pentafluorides from aryl disulfides. However, the teachings of Williams differ from the teachings of Ou in that Williams combines aryl disulfides with AgF2 to form the final aryl sulfur pentafluoride. The general method of Williams is provided in the diagram below (Page 12, Scheme 1):
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Williams further provides an exemplary synthesis wherein 4-nitrophenyldisulfide (50 g) is combined with AgF2 (400 g) and heated to 122-124C for 6 hours in order to form the final nitrophenyl pentasulfide (page 7)4. Williams’ synthesis provided product in 99% purity and a yield of 78% (page 7)5. As the method of Williams appears to provide a higher yield of final product, a person or ordinary skill in the art would be motivated to use AgF2 as a fluorination agent rather than the XeF2 of Ou.
It would have been prima facie obvious at the time of invention for a person of ordinary skill in the art to combine the teachings of Ou and Williams, and substitute the use of XeF2 of Ou, for the AgF2 used by Williams, because there would be a reasonable expectation that the yield of the final aryl sulfur pentafluoride product would be greater.
Claim 2 further limits the method of claim 1 wherein A1 is:
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Ou teaches PhSF5 which is a compound of formula (1) wherein A1 is unsubstituted aryl.
Claim 3 further limits the method of claim 1 wherein the oxidative fluorination reaction is carried out at -40 to 130C.
Ou teaches reaction at 25C.
Claim 4 further limits the method of claim 1 wherein a metal produced after the oxidative fluorination is recovered.
Williams teaches that AgF2 is consumed in reaction to form AgF, which can be collected and re-fluorinated into AgF2 for repeated use (pages 4-5)6.
Claim 5 further limits the method of claim 4 wherein the recovered metal is fluorinated to regenerate a divalent or higher valent metal fluoride, and the obtained divalent or higher valent metal fluoride is used again in the oxidative fluorination reaction.
As iterated in the claim 4 rejection, Williams teaches that AgF2 is consumed in reaction to form AgF, which can be collected and re-fluorinated into AgF2 for repeated use.
Conclusion
Claims 1-5 are rejected.
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
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/ERIC TRAN/Examiner, Art Unit 1629
1 “Thus whilst the excess silver difluoride used in the process of the present invention .represents an expensive capital outlay, the silver may be used effectively as a carrier for the fluorine used in the formation of the sulphurpentafluoride moiety and may be re-cycled repeatedly without serious loss.”
2 “To PhSSPh (17 mg, 0.078 mmol) in CD2Cl2 (0.3 mL) in a ptfe-lined NMR tube was added Et4NCl (2 mg, 0.012 mmol) at 258C. Solid XeF2 (82 mg, 0.48 mmol) was then added slowly to the reaction mixture and the colourless solution turned yellow, with gas evolution. After 30 min, another batch of Et4NCl (6 mg, 0.036 mmol) was added. Gas evolved vigorously and the solution turned deep yellow and back to colourless, to give PhSF5 (25%), identified by 19F NMR”
3 “Arylsulfur pentafluorides have been made previously by the reaction of AgF2 with aryl disulfides or arylsulfur trifluorides”
4 “4-Nitrophenyldisulphide (50g) was charged to the reaction vessel and agitation was commenced. Silver difluoride (400g) was added in one portion to the stirred mixture at ambient temperature from a solid addition funnel designed to maintain an inert atmosphere over the contents during the charging procedure. Last traces of silver difluoride were rinsed into the reactor with (50 mls) of octane. The temperature of the reactor and contents was raised over 2 hours to 122 - 124°C and held at this temperature for 6.5 hours.”
5 “The chloroform eluents were evaporated to give 74 grams of product whose purity was estimated as 99% by HPLC whilst GC analysis indicated 16% octane/hydrocarbon content. The yield was thus 78% (based on disulphide charged and GC analysis of purity).”
6 “Silver difluoride consumed during the reaction is converted to silver fluoride which is also insoluble under the reaction conditions. Silver fluoride and any unreacted silver difluoride remaining after the reaction is complete are thus readily recovered by filtration, optionally with washing using a suitable solvent. Silver difluoride is readily re-formed by the treatment of silver fluoride with a fluorinating agent such as gaseous fluorine. Thus whilst the excess silver difluoride used in the process of the present invention represents an expensive capital outlay, the silver may be used effectively as a carrier for the fluorine used in the formation of the sulphurpentafluoride moiety and may be re-cycled repeatedly without serious loss.”
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