Retrieving Precise Substances Using Element Counts with Generic Groups in CAS REGISTRY SM

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1 Retrieving Precise Substances Using Element Counts with Generic Groups in CAS REGISTRY SM Science IP, The CAS Search Service. CAS REGISTRY, the gold standard for chemical information, contains more than 70 million unique organic and inorganic chemical substances, such as alloys, coordination compounds, minerals, mixtures, polymers and salts. When structure searching in REGISTRY and the other exemplified compound databases, the element counts option with generic groups provides a useful means to conduct broad searches with specific element count requirements. You can apply element counts to generic groups using Query Definition/Element Count in STN Express Structure Drawing. The software gives different element count options depending on the selected generic group (Table 1). The Element Count option applied to generic groups limits the retrieval to an exact number (can be zero), minimum, maximum or range of atoms. For example, you can draw a heterocycle with exactly one oxygen molecule located at any position using the generic heterocycle group (Hy) with an element count of exactly one oxygen. Table 1: Element Count Options for Generic Groups Using Query Definition/Element Count or Query Definition/Generic Definition Generic Group Definition Element Count Options (Exact, Minimum, Maximum or Range) Generic Definition Options Related to Element Count Cy ring element (default) system No. of Heteroatoms: 2 or more OR Exactly 1 No. of Carbons: Hy Heterocycle element (default) No. of heteroatoms: 2 or more OR Exactly 1 No. of carbons: Cb Carbocycle Carbon only (default) No. of carbons: Ak Alkyl Carbon only (default) No. of carbons: The available Generic group options under Query Definition/Generic Definition provide set element counts to select, but lack the specificity of the Element Count option. Either option (Element Count or Generic Definition) can suffice depending on the search query requirements.

2 In the following example, we show how using the Element Count settings in conjunction with Query Definition/Generic Definition (Table 2) together provide a useful way to retrieve the precise structures of interest. Table 2: Generic Definition Options Generic group Type of Chain Note: Applies only to Ak. Number of Hetero Atoms Note: Applies only to Hy and Cy. Note: Applies only to Hy, Cy and Cb. Number of Carbon Atoms Options Unsaturated Saturated Branched Linear 2 or more Exactly 1 Monocyclic Polycyclic 7 or more Less than 7 In our search example, we fixed the structure query, Hy (example below) as always unsaturated and monocyclic, but vary the element count settings. The queries in the example include those with: No element count restriction An element count restriction of minimum of 3 nitrogen atoms Element count requirement of nitrogen and oxygen each with a minimum of 1, and sulfur and phosphorus each with an element count of exactly zero. Example: Search for structures with different element counts for the heterocyclic group (Hy) using the structure query below in CAS REGISTRY.

3 => FILE REGISTRY => Uploading nucleoside hy unlimited.str Hy: - unsaturated, monocyclic - no element count restrictions Generic attributes : 14: : Unsaturated : Monocyclic L1 STRUCTURE UPLOADED => SEARCH L1 SSS FULL L SEA SSS FUL L1 => DISPLAY SCAN L ANSWERS REGISTRY COPYRIGHT 2013 ACS on STN L ANSWERS REGISTRY COPYRIGHT 2013 ACS on STN Continued on next page

4 => Uploading nucleoside hy nitrogen.str Hy: - unsaturated, monocyclic - element count with nitrogen minimum of three Generic Attributes: 14: : Unsaturated : Monocyclic Element Count : Node 14: Unlimited N,Min,3 L4 STRUCTURE UPLOADED => S L4 SSS FULL L6 995 SEA SSS FUL L4 => D SCAN L6 995 ANSWERS REGISTRY COPYRIGHT 2013 ACS on STN CM 2 Continued on next page

5 => Uploading nucleoside hy nitrogen oxygen.str Generic attributes : 14: Element Count : Node 14: Unlimited N,Min,1 S,Exact,0 O,Min,1 P,Exact,0 : Unsaturated : Monocyclic Hy: - unsaturated, monocyclic - element count with - Nitrogen: minimum of 1 - Oxygen: minimum of 1 - Sulfur: exactly 0 - Phosphorus: exactly 0 L7 STRUCTURE UPLOADED => S L7 SSS FULL L9 39 SEA SSS FUL L7 => D SCAN L9 39 ANSWERS REGISTRY COPYRIGHT 2013 ACS on STN L9 39 ANSWERS REGISTRY COPYRIGHT 2013 ACS on STN Rotation (+). This example highlights the use of element count options for cases with unfixed heteroatoms in a heterocycle. The table below (Table 3) summarizes the precision achieved by using element count restrictions based on the decreasing number of hits retrieved with each of the searches.

6 Table 3. Summary of Search Results in the Example Restrictions No element count restriction An element count restriction of minimum of 3 nitrogen atoms Element count requirement of nitrogen and oxygen each with a minimum of 1, and sulfur and phosphorus each with an element count of exactly zero Substances Retrieved (L#) 7828 substances (L3) 995 substances (L6) 39 substances (L9) By using settings for both Element Count and Generic Definition, the search retrieved precise substances meeting both of the requirements. STN provides access to key science, technology and patent databases, and is the premier single source for the world s disclosed scientific and technical research. STN databases such as CAS REGISTRY can be accessed through STN Express, STN on the Web SM and STN Easy. To find more information about the REGISTRY database or other display fields, please contact CAS Customer Center or refer to the CAS REGISTRY Database Summary Sheet at: Note: This search example was provided by Science IP, the CAS Search Service.