Chemical Information Sources/Chemical Patent Searches 1

Chemical Information Sources/Chemical PatentSearchesIntroduction

The patent literature contains a large body of chemical information dating back more than two hundred years. In fact,some of the earliest granted patents were for chemistry-related inventions. The very first U.S. patent (US X1 [1]) wasissued to Samuel Hopkins of Philadelphia on July 31, 1790 for “an improvement, not known or used before suchdiscovery, in the making of Pot Ash and Pearl Ash by a new apparatus and process.” Pot ash (potassium carbonate)and pearl ash (lime) were important ingredients in the production of a number of valuable products including soapand fertilizer. Hopkins also received a patent for his invention in Lower Canada (Quebec) in 1791.Scientific discoveries and industrialization during the nineteenth century spurred the growth of chemistry-relatedpatents. Notable chemical patents of the period include British chemist William Perkin’s 1856 patent for aniline dye,the first synthetic dye; American John Wesley Hyatt’s 1869 patent for making celluloid, the first artificial plastic;Canadian-American Herbert Henry Dow’s 1892 patent for bromine extraction, one of the first of many chemicalprocesses patented by the Dow Chemical Company; and German chemist Felix Hoffmann’s 1900 patent foracetylsalicylic acid, which was marketed worldwide under the trade name Aspirin.Table 1. Notable Chemical Patents of the 19th and 20th Centuries

Number Year Inventor Description

US 3,633 1844 Charles Goodyear (US) Vulcanized rubber

GB 1,864 1856 William Perkin (UK) Aniline dye (first synthetic dye)

US 88,633 1869 John W. Hyatt (US) Celluloid (first synthetic plastic)

US RE 11,232 1892 Herbert Henry Dow (US-Canada) Bromine extraction

US 644,077 1900 Felix Hoffmann (Germany) Acetylsalicylic acid (Aspirin)

US 942,699 1909 Leo Baekeland (US) Bakelite (first commercially successful plastic)

US 971,501 1910 Fritz Haber (Germany) Production of ammonia

US 1,049,667 1913 William Burton (US) Catalytic cracking of petroleum products

US 1,266,766 1918 Jacques E. Brandenburger (Switzerland) Cellophane

CA 234,336 1923 Frederick Banting and Charles Best (Canada) Insulin preparation

US 1,811,959 1931 Julius A. Nieuwland (US) Neoprene (first synthetic rubber)

US 1,929,435 1933 Waldo L. Sermon (US) Polyvinyl chloride (PVC)

US 2,171,765 1939 Otto Röhm (Germany) Process for the polymerization of methyl methacrylate (Plexiglass)

US 2,752,339 1956 Percy L. Julian (US) Preparation of cortisone

US 2,825,721 1958 Robert Banks and J. Paul Hogan (US) High-density polyethylene (HDPE)

Today, patents continue to be vital to the chemical, pharmaceutical, agricultural, materials, energy and biotechnologyindustries. Since 1790 the USPTO has issued more than 8 million patents. U.S. patent 8,000,000 was issued onAugust 16, 2011. The total number of patent documents worldwide is estimated to be more than 70 million. In 2010inventors filed approximately 1.98 million new patent applications around the world. Of these, approximately 22percent were chemistry related. (WIPO, 2011 [2])Most patents of interest to chemists cover compositions of matter (new chemical compounds, mixtures,pharmaceuticals) or processes (e.g., synthesis of a drug). Under the patent laws of some countries it is even possibleto patent things such as 3D atomic structures, structural databases, biological sequences, and their uses, which may

Chemical Information Sources/Chemical Patent Searches 2

result from the genomics field. Other types of patents are issued for machines, products, business methods, plantsand industrial designs. With hundreds of thousands of patents issued annually by various countries, a great deal ofeffort is necessary to organize patent documents for effective retrieval and analysis.Patent offices disseminate patent information in a variety of ways. Historically, this was done by publishing abstractsof issued patents and printed copies of patents. In the U.S. and a few other countries, copies of patents weredistributed to academic and public libraries designated as patent depositories. Beginning in the mid-1990s, patentoffices utilized the internet to disseminate patent information. In 1994 the USPTO launched the first public patentdatabase on the internet. The European Patent Office (EPO) launched its Espacenet [3] patent database in 1998.Patent offices also sell patent data (at nominal prices) to commercial patent information companies, most notablyThomson Reuters [4], IFI CLAIMS [5], LexisNexis [6], and Questel [7], that incorporate it into their databaseproducts. The internet abounds with free patent databases created by academics, librarians, entrepreneurs, collectors,and patent enthusiasts. Some of the most notable include Google Patents [8], FreePatentsOnline [9] and Patent Lens[10].Patents are covered in many chemical literature abstracting and indexing services. One of the most important ofthese is Chemical Abstracts, which is published by the Chemical Abstracts Service [11], a division of the AmericanChemical Society. The online version of CA is called SciFinder. CA/SciFinder currently includes patents from morethan 60 countries. Approximately 18 percent of the documents indexed in CA/SciFinder are patents.

What is a Patent?

A PATENT is a grant of property rights to an inventor by a government for a limited time, generally 20 years.Patents may be sold, licensed, transferred or bequeathed. Patent rights are exclusionary in nature. Patent owners havethe right to exclude others from making, using, importing or selling the invention in the country (or countries) wherethe patent was issued. The prohibition on importation extends to products made by a patented process. Patents arepart of a group of materials generally referred to as INTELLECTUAL PROPERTY that also includes copyrights,trademarks, designs, trade secrets, new plant varieties and traditional knowledge.To obtain a patent, the inventor must file certain documents, and the invention itself must exhibit the qualities ofNOVELTY, UTILITY (usefulness), and INVENTION (unobviousness, ingenuity), defined as follows:•• Novelty: The concept that the claimed invention must be totally new. The invention must never have been made

public in any way, anywhere in the world, before the date on which the patent application is filed. In the U.S.prior to 2011 this was determined by the date of invention.

•• Utility: The invention has some practical utility, and is fit for some practical, desirable or commercial purpose.For a chemical, utility might mean that it shows a beneficial property, such as a pharmacological effect, or itmight be an intermediate that is used in synthesizing a product that has an end use.

• Invention/ingenuity: The invention must not be obvious to an observer who is "skilled in the art". This assumesthat the claims defining an invention in a patent application must involve an inventive step that, when comparedwith what is already known (i.e., PRIOR ART), would not be obvious to someone who is an expert in that field.

In addition, the invention must be disclosed in a clear and complete manner in the patent application. There can beno secret ingredients or information withheld from the application. This is known as the DISCLOSURErequirement.Patent searching is often undertaken in order to prove novelty, either prior to filing a patent application or during the prosecution of a patent application. This process is known as PRIOR ART SEARCHING or PATENTABILITY SEARCHING. In this case, the older patent literature is quite important. A second type of patent search involves INFRINGEMENT, i.e., trying to determine whether someone else is illegally claiming the rights to an invention that is yours. In this case, the search must be exhaustive, but is limited to the last 20 years or so. VALIDITY searches are conducted in order to locate prior art that invalidates one or more claims in a published application or issued patent. CLEARENCE searches (also known as “freedom-to-operate” or “right-to-use”) are conducted prior to

Chemical Information Sources/Chemical Patent Searches 3

using a process or manufacturing a product that might be patented by another party. STATE-OF-THE-ARTsearches are comprehensive searches of the patent and non-patent literature conducted to determine the current stateof development of a specific technology or technical field.The inventor is the PATENTEE, and the inventor may assign the patent protection rights to another person orcompany, the ASSIGNEE. The inventor submits the first patent application on a certain date known as thePRIORITY APPLICATION DATE. Under the "Paris Convention for the Protection of Intellectual Property of1883," the priority date is also considered to be the date a patent application is filed in any country that has signedthe Paris Convention (as long as the inventor files the application in the other country within 12 months of thepriority date). This results in a PATENT FAMILY of publications related to the invention. Some of these may bepatents (perhaps in a language that is easier to read than that of the original), whereas others merely document theinvention disclosed by the applicant as of the priority date. Regional patenting bodies, such as the European PatentOffice, issue patents for groups of countries, and the Patent Cooperation Treaty [12] permits a single filing to initiatethe patenting process in a number of countries. The PCT now provides for filing in over 100 countries. Theimportance of the priority date becomes very obvious when cases arise where two companies file for the sameinvention at about the same time. Such was the case when ICI Ltd. filed EP 399731 [13] with a priority date of 23May 1989, and Merck & Co. filed EP 400974 [14] on 30 May 1989.

What is Not Patentable?

Patents will not be granted for an invention that has already been publicly disclosed in another patent application orarticle, or through public use or sale. Even a posting on the internet can negate the criterion of novelty. In the U.S.,an inventor cannot obtain patent protection if an article is published about the invention more than one year beforethe filing is made. In other parts of the world the patent would be invalidated on the first day of publication of thearticle. Much of the information in the patent literature is, in fact, never published in any other format. However,some chemists denigrate patents as information sources since the titles, descriptions, and claims tend to use general,broad terminology, rather than the precise wording typically found in journal articles or other forms of primaryscientific literature.In general, patents are not granted for discoveries, scientific theories and naturally occurring substances. Inventionsthat are deemed to be contrary to the public good (terrorist devices) or having national security implications (nuclearweapons) may be unpatentable. Some countries restrict or prohibit patenting of diagnostic, therapeutic and surgicalmethods of treatment for humans or animals.

What is a Patent Specification?

Patent searching is complex, and a basic understanding of the patenting process is necessary in order to comprehendthe different types of documents involved. Most countries publish patent applications 18 months after the filing orpriority date. In addition, a second patent document may be issued after the patent is granted. Other types of patentdocuments include REISSUE PATENTS, DEFENSIVE PUBLICATIONS, STATUTORY INVENTIONREGISTRATIONS, CERTIFICATES OF CORRECTION, and CERTIFICATES OF REXAMINATION.Some countries permit inventors to file PROVISIONAL PATENT APPLICATIONS. Provisional applications arenot examined or published but may be cited in a later patent application. When the inventor applies for a patent, thePATENT SPECIFICATION must be submitted. The specification is a technical document that contains adescription of the invention. A typical patent document will include drawings, background of the invention, asummary and a detailed description of the invention, examples, and one or more CLAIMS that define what is legallycovered by the invention. The FRONT PAGE of a published patent specification contains bibliographicinformation, an abstract and selected drawing.Published patent documents are assigned unique identification numbers. The standard format for a patent number is the two-letter COUNTRY CODE followed by the SERIAL NUMBER followed by a one- or two-letter KIND

Chemical Information Sources/Chemical Patent Searches 4

CODE. For example, US 7,000,000 B1 is the number of a U.S. patent and CA 2683867 A1 is the number of aCanadian published application. Older patent numbers may not have country or kind codes. Country codes [15] arefairly obvious, e.g. US for United States, CN for China, GB for Great Britain, DE for Germany, JP for Japan, etc.The country code for patent numbers assigned by the European Patent Office is EP; WO is reserved for PCTapplications published by the WIPO. Kind codes [16] indicate the type of document. The code “A” is for publishedapplications (first-stage publications) and search reports; “B” and “C” are reserved for issued patents. Other kindcodes include “S” for U.S. design patents and “P” for U.S. plant patents. Numbering systems vary by patent office.Some patent offices use a continuous number system while others use a year-number system; some offices use bothsystems. For example, the USPTO began numbering patents in 1836; patent 1 was issued on July 13 of that year.This series continues up to the present day, with patent 8,087,093 being issued on December 27, 2011. When theUSPTO began publishing applications in 2001, it decided to number them using a year-number format. The numberassigned to the first application published each year from 2001 forward is 2001/0000001, 2002/0000001,2003/0000001, 2004/0000001, etc. In contrast, the Canadian Intellectual Property Office assigns one number to eachapplication and simply updates the country code at each stage, e.g. CA 2,258,975 A1 for the published applicationand CA 2,258,975 C for the issued patent.Most countries allow the inventor to define the legal limits of the patent in the claims in both generic terms andspecific terms. For chemical patents, generic inventions usually take the form of a MARKUSH STRUCTURE, astructure that contains one or more structural variables based on a list of stated alternatives. Each compound thatcould be constructed from the list is covered by the claims. Click here for an example of a very long MarkushStructure [17].

How Long Does a Patent Last?

In the past there was a great deal of variation in the terms of protection afforded by patents issued in differentcountries. In the early 1990s, members of the World Trade Organization (formerly the General Agreement on Tariffsand Trade) agreed to recognize patents in all fields of technology for a 20-year period that begins with date of thefirst patent application filed in any country, also known as the PRIORITY DATE. On June 8, 1995, the new termtook effect in the U.S. Prior to that date U.S. patents were issued for a term of 17 years from the date of issue. Designpatents, which protect original ornamental designs, and utility models, which protect minor improvements, havemuch shorter terms, generally 5-14 years.

Classification of Patents

Patent classification systems provide a means to organize, store and retrieve patent documents efficiently andeffectively. There are several patent classification systems in use today, all of which are organized around technicalsubject matter. The most widely used is the International Patent Classification [18] (IPC). IPC is a hierarchicalclassification that consists of eight sections, labeled A through H. Section C covers chemistry and metallurgy. Eachsection is further subdivided into classes, subclasses, and groups. There are approximately 70,000 IPC codes.Chemical compounds are classified in section C according to their chemical structures. For example, C07C 31/18 isthe IPC code for polyhydroxylic acyclic alcohols. Chemical processes and apparatus are located in class B01.Pharmaceutical compounds are classified in subclass A61K, Preparations for Medicinal, Dental, or Toilet Purposes.The European Classification (ECLA) [19], which is maintained by the EPO, is based on the IPC and uses many of thesame codes. However, ECLA has about 140,000 codes, almost twice as many as the IPC. In 2010, the EPO andUSPTO announced that ECLA will be the basis of a new Cooperative Patent Classification (CPC) to be implementedin 2012.The U.S. Patent Classification (USPC) [20] is used only by the USPTO. The USPC consists of approximately 450 classes and 150,000 subclasses. There are dozens of USPC classes relating to chemistry. The three largest in terms of total patents are Class 520-528, Synthetic Resins or Natural Rubbers, which has 217,166 patents; Class 532-570, Organic Compounds, with 231,160 patents; and Classes 424 and 514, Drug, Bio-Affecting and Body Treating

Chemical Information Sources/Chemical Patent Searches 5

Compositions, with 175,826 patents. The USPC will be phased out in 2012 in favor of a new classification systemjointly developed by the EPO and USPTO.

Abstracting and Indexing of Patents: Major Patent Databases

Since patents for a particular invention may appear at different times in a number of countries, abstracting andindexing services generally have adopted the practice of abstracting only the first patent issued, called the BASICPATENT. Later patents in the patent family are indexed as EQUIVALENT PATENTS. Database producers are notalways in agreement when it comes to a definition of basic and equivalent patents. On STN, members of a patentfamily have a common priority application number and date. Further complicating the patent family situation are thepatent types that may result in related patents, namely:•• Division: results from a decision by the patent office that the claims are too broad for a single patent. The

application is then split into a parent and divisional applications, each claiming a different invention•• Continuation: results when a second and subsequent applications are filed when the original application is

pending•• Continuation-in-Part (CIP): results from a second or subsequent application being filed that includes new material

even though the original application is pending.USPTO Patent Databases

The USPTO was the first patent office to use the internet to disseminate patent information, launching its first patentdatabase in 1994. Today the USPTO website hosts two patent databases, one for issued patents (PatFT [21]) and onefor published applications (AppFT [21]). PatFT is updated weekly on Tuesdays and AppFT is updated weekly onThursdays. Full-text searching is available for patents issued from 1976 forward and published applications from2001 forward. Prior to 1976, patents may be retrieved by number, date of issue and current USPC or IPCclassification. Patent document images are stored in TIFF format and require a TIFF viewer to display and print.Searching by chemical structure, formula or registry number is not available. The USPTO website also hosts atrademark database that is useful for locating chemical trade names; a patent and trademark assignments databasethat contains records of assignment changes; and PAIR, Patent Application Information Retrieval, which containspatent prosecution histories, legal status information and file wrapper documents.FreePatentsOnline

FreePatentsOnline [9] is a free patent database owned by SumoBrain Solutions Co. It currently offers full-textsearching of USPTO, EPO, WIPO/PCT documents from the mid-1970s forward. Patent abstracts of Japan andnon-patent literature collections are also searchable. The U.S. national collection contains about 28,000 records forwithdrawn patents that are not included in the USPTO databases. Withdrawn patents are applications that have beenapproved by the USPTO but withdrawn by the applicant (or USPTO) prior to issue. US, EP and WO documents arestored in PDF format. Full-text searching is not available prior to 1976. US patents from 1836 to 1975 are availablein PDF and may be retrieved by number, date of issue and classification. Searching by chemical structure, formula orregistry number is not available.ChemSpider

ChemSpider [22] is an award-winning free chemical information search engine owned by the Royal Society ofChemistry. It provides access to over 25 million chemical structures, properties and other information from morethan 400 vetted data sources. Search options include systematic name, synonym, trade name, registry number,SMILES, InChI, CSID, structure and properties. Patent data is sourced from Google Patents and SureChem [23], aproprietary chemical patent database. Patent coverage includes USPTO, EPO, WIPO/PCT patent documents andJapanese patent abstracts from the late 1970s forward. A subscription to SureChem is required to see more than thefirst three patents retrieved in a search result.Cippix

Chemical Information Sources/Chemical Patent Searches 6

Cippix [24] covers USPTO, EPO, WIPO/PCT, CA, DE patent documents and Japanese full text documents. Cippixextracts chemical entities automatically from English, German, French, and Japanese sources with weekly updates.Cippix provides advanced proximity searches on compound and document level. Subscription to Cippix is requiredand can be purchased online for immediate access.INPADOC [25], the International Patent Documentation Center, covers about 60 country patent offices as well asinternational patent bodies, such as WIPO and EPO (the European Patent Office [26]). Therefore, the INPADOCdatabase is a major source of patent family data and forms the basis for Chemical Abstracts Service's printed patentindexes, and now the data found in the CA and CAPlus files.IFI CLAIMS [5] files cover U.S. chemical patents from 1950.Derwent, now a Thomson Reuters [4] company, developed one of the world's largest patent services, covering over30 countries plus the European Patent Office and Patent Cooperation Treaty countries. The WPI (World PatentsIndex) database covers pharmaceuticals from 1963 and other categories of chemicals for the periods shown below:•• Pharmaceuticals, 1963-•• Agricultural chemicals, 1965-•• Plastics and polymers, 1966-•• All other chemistry, 1970-Derwent also produced the Derwent Patents Citation Index covering US Examiner's citations from 1984 and EPOand PCT Examiner citations from 1978.See a sample search of the WPINDEX file [27] and STN's Database Summary Sheet for WPINDEX [28].Questel [29] offers Markush structure searching in the WPIM and PHARMSEARCH files. PHARMSEARCH coversUS and European pharmaceutical patents from 1984 to the present, and WPIM has all of the Derwent chemical andpharmaceutical patents. The Merged Markush Service [30] is a structure file produced by INPI [31] (the French Patentand Trademark Office) and Derwent that can be searched by generic structure input. MMS includes all of thestructures previously available in the MPHARM (Markush PHARMSEARCH) and DWPIM (Derwent WorldPatents Index Markush) files. MMS also includes all the compounds from the Derwent Chemical Resource (DCR).A new database on Questel is PlusPat, a source of worldwide patent data that extends back into the 19th century.PlusPat merges the European Patent Office (EPO) DOCDB file, (which is the basis for EPO databases - includingEsp@cenet [32]), with information from additional Questel databases.

CAS Patent Databases on STN

Chemical Abstracts Service's coverage of patents began with the print CA in 1907. Enhanced coverage of patentswas initiated around 1960. In 1999, CAS began to include patent family information in its CAplus file. There are twotypes of patent family relationships in CAplus.•• Closely related family members: have a simple priority application relationship. These are usually included in a

single record in CAplus.•• Extended patent family members: result from complex relationships.

•• Multiple, but at least one, common priority applications from different countries•• Relationships resulting from division, addition, continuation, or continuation-in-part patents

Additional records may be created by CAS in order to capture any new information that is included in these familymembers. Patent coverage is extremely fast in CAplus now, with most chemical patents making it into the databasewithin two days of issue.STN now has a Markush database in the MARPAT file [33] (1988- ). MARPAT [34] provides access by structure toall the specific and generic substances claimed in patents via Markush structures from 1988 to the present.USPATFULL has the full text of all patents issued by the USPTO from 1975 (with partial coverage from 1971-74). The US Patent Office began to publish US patent applications on March 15, 2001, so the USPATFULL database

Chemical Information Sources/Chemical Patent Searches 7

now includes those documents. They are distinguished from the granted patents by their kind code, A1. CAS indexeschemical patents in USPATFULL, including CAS Registry Numbers. See the example for the USPATFULL [35] fileon STN, which has a thesaurus for the USPTO Manual of Classifications and for the WIPO IPC.The USPATOLD (U.S. Patents Pre-1976) database includes more than 3.5 million records, namely, the full text ofpatents issued by the USPTO from 1790 through 1975. These records were created from original U.S. patentdocuments that were converted into electronic form through an optical character recognition process. Since OCR isnot 100% accurate, some records may include misinterpreted characters, or portions of the patent text may bemissing. To enhance their retrieval, approximately 500,000 USPATOLD records that are also covered by CApluswere supplemented with CAS data.

Examples of Chemical Patents

Note the increase in the US patent numbers issued during the years covered by the table below.

Issuing Body Patent Number Year Title

USPO 2,167,351 1939 Piperidine compounds and a process of preparing them

USPO 2,248,018 1941 4-Aryl-piperidine-ketones and a process of preparing them

USPO 2,479,295 1949 Process and culture media for producing new penicillins

USPO 2,840,577 1958 17-Thio derivatives of Estratrien-3-ol and of Estratetraen-3-ol

USPO 3,903,094 1975 Piperidyl glycolates

USPO 4,150,158 1979 Oxadiazindione derivatives useful as insecticides

USPO 4,284,794 1981 Prostaglandin derivatives

EPO 0 274 909 A2 1987 Hydrocarbon oxidations catalyzed by azide- or nitrid-activated metal coordination complexes

USPO 4,900,871 1990 Hydrocarbon oxidations catalyzed by iron coordination complexes containing a halogenated ligand

USPO 5,245,036 1993 Process for the preparation of 4-phenoxyquinoline compounds

The CA abstract for the last patent above is reproduced below:

Process for the preparation of 4-phenoxyquinoline compounds useful as fungicides. Robery, Roger L.; Alt, Charles A.; DeAminis, Carl V. (DowElanco, USA). U.S. (1993), 4 pp. CODEN: USXXAM US 5245036 A 19930914 Patent written in English. Application: US 92-879488 19920507.

CAN 120:30682 AN 1994:30682 CAPLUS

Patent Family Information

Patent No. Kind Date Application No. Application Date

US 5245036 A 19930914 US 1992-879488 19920507

JP 06041083 A2 19940215 JP 1993-124804 19930430

EP 569021 A1 19931110 EP 1993-107392 19930506

R: CH, DE, DK, ES, FR, GB, IT, LI, NL

PriorityApplicationInformation

Date

US1992-879488

19920507

Abstract

Chemical Information Sources/Chemical Patent Searches 8

4-Phenoxyquinolines I [R1, R2 = H, halo, alkyl, haloalkyl; R3, R4 = H, halo], which are known plant fungicides (no data), are prepd. byetherification of corresponding 4-haloquinolines with phenols HOC6H3R1R2 in the presence of a catalytic amt. of a 4-dialkylaminopyridine. Thecatalyst accelerates an otherwise sluggish reaction, thereby shortening batch cycle times and effectively enlarging manufg. capacity. Thus, reaction

of 0.01 mol 4,7-dichloroquinoline with 0.014 mol 2-CF3C6H4OH in refluxing xylene contg. 0.0015 mol 4-dimethylaminopyridine showedcomplete conversion after 24 h. Isolation of the product via formation, filtration, and neutralization of the HCl salt, gave 89% I (R1 = 2-CF3, R2 =

R4 = H, R3 = 7-Cl). Two addnl. I were similarly prepd. in 86-93% yield and reaction times of 16-18.5 h. Also used as catalysts were4-pyrrolidinopyridine and polyDMAP (polymer-bound 4-aminopyridine from Reilly Industries, Inc.).

Sample CAPlus Entry for A Chemical Patent (Partial Record)(Reproduced with permission of CAS, a division of the American Chemical Society.)

Miscellaneous

Derwent Fragment Codes offer a way to conduct chemical searches on the Derwent files, such as WPI. Millions ofpatents were not indexed for searching by structure using graphic input, so the codes developed by Derwent need tobe used. In the World Patents Index, these codes serve as links for all patents in appropriate subject areas as far backas 1963 for pharmaceutical patents. As noted above, WPI also has a Markush searching capability for more recentpatents in the pharmaceutical, agrochemical, and chemical subject sections. They also have a polymer coding systemcovering 1966 onward.The IFI Comprehensive Index and the IFI Uniterm Index provide a type of chemical substructure search capabilityfor US patents to at least 1964. The American Petroleum Institute databases, APIPAT and APILIT, utilize a systemof very broad fragmentation codes to index patents and technical literature, respectively. Coverage is not limited topetroleum, but extends to a wide range of petrochemicals, such as hydrocarbons and oxygenates. The files werepurchased by Elsevier in 1999 through its Engineering Index division. They are now available on STN asENCOMPPAT and ENCOMPLIT, as are the IFI files.Since patent rights can be assigned, it is sometimes difficult to determine who owns the rights to an invention. TheUSPTO keeps track of patent assignees, but new owners are not required to notify anyone when an invention haschanged hands. There is an IFI CLAIMS/Reassignments file. In addition, there are databases that keep track of legalchallenges to a patent, but those simply report the fact of the challenge. Legal databases, e.g., Lexis-Nexis orWestLaw, can be consulted for the outcomes of such challenges.

Summary

The patent literature is very different from other types of primary chemical literature. Some chemists dismiss thepatent literature because of the lack of sufficient detail in many chemical patents to permit the patented process orcompound(s) to be replicated easily. Nevertheless, the patent literature worldwide forms a large chunk of the primarycoverage in Chemical Abstracts. Several specialized commercial databases exist for the chemical patent literature,some with Markush searching capabilities that unearth the many compounds that can be buried in patent claims. TheWeb has provided easy avenues to obtain patent documents and some free database search options.To obtain a copy of a US patent (and other patents) in pdf format, try: esp@cenet [36].To obtain a pdf copy of a US patent, go to pat2pdf.org [37].CIIM Link for further studySIRCh Link for Chemical Patent SearchesProblem Set on this topic [38]

Chemical Information Sources/Chemical Patent Searches 9

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Article Sources and Contributors 10

Article Sources and ContributorsChemical Information Sources/Chemical Patent Searches  Source: http://en.wikibooks.org/w/index.php?oldid=2262319  Contributors: Adrignola, Avicennasis, Gary Dorman Wiggins,Mjwhitekingston, 33 anonymous edits

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