Lesson 7: Substance Searching Using CAS Registry Numbers

Objectives: To learn about CAS Registry Numbers and why you need to include them in searches for references on specific substances. Three techniques will be shown for finding CAS Registry Numbers; searching chemical names, name segments, and molecular formulas. Also, you will learn how to obtain references describing preparation of a specific compound.

Topics:

References: Database summary sheet for the Registry File ; Quick Reference Card on How To Search CAS Registry Numbers; and the Registry File Dictionary Searching Manual.

CAS Registry Numbers

The key to finding references on a specific substance in the CA file is the CAS Registry Number for that substance. CAS Registry Numbers are unique identifiers for chemical compounds. CA and LCA records contain CAS Registry Numbers for all the substances that have been indexed by CAS from a particular document.

The CAS Registry Numbers are displayed in the IT (Index Term) field. 


IT   63160-13-4
       (oxidn. by, of enolates)
CAS Registry Numbers are searchable in the Basic Index of the CA file.

So, in general, the most effective (most comprehensive and most precise) strategy for finding information on a particular substance in the CAS database is to search the CAS Registry Number for that substance. In this section we'll show how to find CAS Registry Numbers and how to search them in order to find references in the CA file.

Finding CAS Registry Numbers

You may find CAS Registry Numbers in various printed sources such as catalogs (e.g. Aldrich). Printed publications from Chemical Abstracts Service also include CAS Registry Numbers. For example, the CA Index Guide contains many cross-references from common names to CA Index names and CAS Registry Numbers. The CA Formula Index provides CA Index Names and CAS Registry Numbers for substances with a particular molecular formula. The CA Chemical Substance Index includes CA index names with the corresponding CAS Registry Numbers.

You can also search for CAS Registry Numbers online on STN in Registry File.

Finding References to Specific Substances

The Registry File contains information for over 13 million substances. The Registry File is like a dictionary of chemical substances. Each record contains all information on one substance. You can search such information as a common or CA Index name, chemical name segment, molecular formula, or structure.

For practice searching, the LREGISTRY File may be used. LREGISTRY contains all the substances indexed in the LCA file. The substance information for compounds in LREGISTRY is the same as that in the Registry File.

Once you find the CAS Registry Number, you can use it as a search term in the CA File to obtain references in which that substance was indexed.

There are basically two approaches to searching for references on a particular substance. If you already have the CAS Registry Number, search it in the Basic Index of the CA file and you obtain all the references in which this particular substance was indexed.

The other approach is to find the CAS Registry Number in the Registry File and then transfer it to the CA file.

Several examples of how to find CAS Registry Numbers in the Registry File will be shown to illustrate the basic techniques that can be used, depending on what type of information you have about the substance.

Searching Chemical Names

The Chemical Name (/CN) index in the Registry File contains all types of names for substances; CA index names, IUPAC names, and other names that CAS has encountered in the literature such as commonly used names or trade names.

Only complete names of chemical compounds are searchable in the Chemical Name field. To search the name, follow the name with the field code /CN. As always, it's a good idea to check with the EXPAND command if the name that you have is present in the index. Make sure that you include any spaces or other punctuation. To EXPAND on a name, follow the name with /CN to tell the system that you want to check the name in the Chemical Name index. Using the EXPAND command in the Registry file is useful to verify the name or to possibly find related compounds.

You can then search the E-number obtained in EXPAND! 


=> FILE REGISTRY

=> E FENTANYL/CN
E1           1     FENTANEST/CN
E2           1     FENTANIL/CN
E3           1 --> FENTANYL/CN
E4           1     FENTANYL CITRATE/CN
E5           1     FENTANYL CITRATE MIXTURE WITH DROPERIDOL AND ACEPROMAZ
		   INE MALEATE AND ATROPINE SULFATE/CN
E6           1     FENTANYL CITRATE-DROPERIDOL MIXT./CN
E7           1     FENTANYL CITRATE-DROPERIDOL-ACEPROMAZINE MALEATE-ATROP
		   INE SULFATE MIXTURE/CN
E8           1     FENTANYL-DROPERIDOL MIXT./CN
E9           1     FENTANYL-PENTOTHAL MIXT./CN
E10          1     FENTANYL-XYLAZINE MIXT./CN
E11          1     FENTAPTON/CN
E12          1     FENTATHIENIL/CN

=> S E3
L1           1 FENTANYL/CN
You can display the information about a substance in the Registry File. The IDE format shows all substance identifying information. Other possible display formats are listed on the Registry File database summary sheet. You can display any field, for example, RN to see just the CAS Registry Number for that particular substance.

The IDE display format is the default display format in the Registry file.

Notice some of the fields present in Registry File records;

The structure diagram is also displayed. You may display the structure on any type of terminal or personal computer you have. Those systems supporting graphics display are recommended. In these examples, structures are shown as they appear on a graphics terminal.

Notice that the HIT name, i.e., the name that caused the retrieval, is highlighted by asterisks. 


=> D L1 1 IDE

L1   ANSWER 1 OF 1  COPYRIGHT 1994 ACS
RN   437-38-7  REGISTRY
CN   Propanamide, N-phenyl-N-[1-(2-phenylethyl)-4-piperidinyl]- (9CI)
     (CA INDEX NAME)
OTHER CA INDEX NAMES:
CN   Propionanilide, N-(1-phenethyl-4-piperidyl)- (7CI, 8CI)
OTHER NAMES:
CN   1-Phenethyl-4-(N-phenylpropionamido)piperidine
CN   1-Phenethyl-4-N-propionylanilinopiperidine
CN   Fentanest
CN   Fentanil
CN     ***Fentanyl***
CN   Phentanyl
CN   R 4263
FS   3D CONCORD
DR   80832-90-2
MF   C22 H28 N2 O
CI   COM
LC   STN Files:   ANABSTR, BEILSTEIN*, BIOBUSINESS, BIOSIS, CA, CAOLD,
     CAPREVIEWS, CEN, CHEMLIST, CIN, CJACS, CSNB, DRUGNL, EMBASE,
     HODOC*, HSDB*, IPA, MEDLINE, MSDS-OHS, MSDS-SUM, PHAR, PNI,
     RTECS*, USAN
     (*File contains numerically searchable property data)
     Other Sources:   EINECS**, WHO
     (**Enter CHEMLIST File for up-to-date regulatory information)



	       6 REFERENCES IN FILE CAPREVIEWS
	    1264 REFERENCES IN FILE CA (1967 TO DATE)
	      46 REFERENCES TO NON-SPECIFIC DERIVATIVES IN FILE CA
	      20 REFERENCES IN FILE CAOLD (PRIOR TO 1967)

L-Number Crossover from Registry to CA

Once you do a search in the Registry File, you can search the resulting L-number in the CA File, thus saving you having to type in the CAS Registry Number.

The following example shows this crossover of an L-number from Registry to CA. The HIT format is used in the CA file to show just the index entry containing the hit search term, i.e. The CAS Registry Number for fentanyl. 


=> FILE REGISTRY

=> S FENTANYL/CN
L1     1 FENTANYL/CN

=> FILE CA

=> S L1
L2     1264 L1

=> D L2 HIT 550

L2   ANSWER 550 OF 1264  CA  COPYRIGHT 1994 ACS
IT   57-27-2, biological studies   ***437-38-7***
     (cardiovascular and metabolic effects of, in heart-lung prepns.)

Finding CAS Registry Number When You Have a Molecular Formula And Name Fragments

Question: Find the CAS Registry Number for the compound with this structure.

In this case we have a structure diagram for which we might be able to generate a name. If we have a name, we could do a Chemical Name search in the /CN field to find the CAS Registry Number. However, it may be easier to generate a molecular formula from the structure. If you have access to the printed CA Molecular Formula Index, you could find CA Index Names and CAS Registry Numbers there. In this example, we'll use the Registry File online to search the molecular formula first.

Molecular Formula (/MF)

The first step is to calculate the molecular formula and arrange the elements in Hill order. For carbon-containing compounds, the Hill order means that carbons are listed first, hydrogens are listed next, and all other elements are then listed in alphabetical order. For compounds that do not contain carbon, simply arrange the elements in alphabetical order and indicate the number of each element.

EXPAND on the molecular formula followed by /MF to indicate that you want to look in the molecular formula index. EXPAND is useful to both verify the search term, find the number of compounds with that search term, and to see related molecular formulas.

In this example, EXPAND on the molecular formula showed that there are many substances with that molecular formula. Consequently, further refining of the answers needs to be done. 


=> FILE REGISTRY

=> E C14H18N4O3/MF

E1           1     C14H18N4O2TL/MF
E2           1     C14H18N4O2ZR/MF
E3         248 --> C14H18N4O3/MF
E4           1     C14H18N4O3.(C2H4O)NC15H24O/MF
E5           1     C14H18N4O3.(CH2O)X/MF
E6           1     C14H18N4O3.1/2CL4PT.H/MF
E7           1     C14H18N4O3.1/2H2O4S/MF
E8           1     C14H18N4O3.2C2H6O3S/MF
E9           1     C14H18N4O3.2C7H3IN2O3/MF
E10          1     C14H18N4O3.2C7H6O2/MF
E11          3     C14H18N4O3.2CLH/MF
E12          3     C14H18N4O3.BRH/MF

Name Fragments

To reduce the number of answers from the molecular formula search, combine the molecular formula search with name fragments in the Basic Index of the Registry File. 



=> S E3 AND BUTYL
	   248 C14H18N4O3/MF
	526169 BUTYL
L1          28 C14H18N4O3/MF AND BUTYL

=> S L1 AND AMINO AND METHYL
       1927517 AMINO
       6665678 METHYL
L2          10 L1 AND AMINO AND METHYL
When you have a reasonably small answer set, displaying the answers may be more effective than adding more search terms.

The DISPLAY SCAN option may be used if you just want to evaluate the the answers. DISPLAY SCAN in Registry provides the CA index name, molecular formula, and structure diagram for each substance and it is FREE. However, answers are not labeled and CAS Registry Numbers are not provided.

In this example, since we need to find the CAS Registry Number for the structure, we can display the RN field (CAS Registry Number) along with the Index Name (IN) and the structure diagram (STR). 


=> D RN IN STR 1-10

L2   ANSWER 1 OF 10  COPYRIGHT 1994 ACS
RN   125705-88-6  REGISTRY
IN   ***Carbamic acid, [5-[(3-methyl-1-oxobutyl)amino]-1H-benzimidazol-2-yl]-,
      methyl ester (9CI)***




			    .
			    .
			    .
			    .

L2   ANSWER 10 OF 10  COPYRIGHT 1994 ACS
RN   17804-35-2  REGISTRY
IN   ***Carbamic acid, [1-[(butylamino)carbonyl]-1H-benzimidazol-2-yl]-, methyl
     ester (9CI)***

Searching For Preparations

To find references on preparations of a specific substance, search the CAS Registry Number followed by P in the CA file. 


=> FILE CA

=> S 84-74-2P
L1         138 84-74-2P
If you have already done a search in the Registry File, go to the CA file and then search L# obtained from the substance file search and follow it by /P.

The following example shows a search for the CAS Registry Number of dibutyl phthalate followed by a search for references dealing with preparation of that substance. 


=> FILE REGISTRY

=> E DIBUTYL PHTHALATE/CN
E1           1     DIBUTYL PHOSPHORODIAMIDATE/CN
E2           1     DIBUTYL PHOSPHORODITHIOATE/CN
E3           1 --> DIBUTYL PHTHALATE/CN
E4           1     DIBUTYL PHTHALATE-ETHYLENE GLYCOL-TEREPHTHALIC ACID PO
		   LYMER/CN
E5           1     DIBUTYL PHTHALATE-VINYL ACETATE-VINYL CHLORIDE COPOLYM
		   ER/CN
E6           1     DIBUTYL PHTHALYL-BIS-GLYCOLATE/CN
E7           1     DIBUTYL PIMELATE/CN
E8           1     DIBUTYL PIMELATE-DIETHYLENE GLYCOL COPOLYMER/CN
E9           1     DIBUTYL PIPERAZINE-1,4-BIS(CARBODITHIOATE)/CN
E10          1     DIBUTYL PIPERIDINOMETHYLPHOSPHONATE/CN
E11          1     DIBUTYL PIPERIDINOPHOSPHONATE/CN
E12          1     DIBUTYL POLYETHYLENE GLYCOL PHOSPHATE/CN

=> S E3
L1           1 "DIBUTYL PHTHALATE"/CN

=> FILE CA

=> S L1/P
L2         138 L1/P


=> D SCAN

L2    138 ANSWERS   CA  COPYRIGHT 1994 ACS
CC   22-8 (Physical Organic Chemistry)
TI   Thermal analysis of .beta.-substituted phthalic acid diesters
ST   phthalate dialkyl thermal stability; pyrolysis dialkyl phthalate
     kinetics
IT   Kinetics of thermal decomposition
	(of dialkyl phthalates)
IT   ***84-74-2P***     2553-24-4P   4131-84-4P   83415-90-1P
     83646-71-3P
	(prepn. and thermal decompn. of, kinetics and mechanism of)

HOW MANY MORE ANSWERS DO YOU WISH TO SCAN? (1):0
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