Using I Lab via ChemSketch 

Let: 

n

n

n

a

x

b

x

c

x x

jA

jB

jA

jB

j

1

j

1

j

1

. 

Let m be the value of the Minimum Coefficient list.  The following table describes how Web DB 

searches records by similarity for each item of the Similarity Coefficient list: 

Coefficient 

Parameter 

Condition 

Tanimoto 

Dice 

Cosine 

Based on Hamming Distance 

Based on Euclidian Distance 

If the condition is fulfilled, the record containing structure B will be shown as a result of the 

search. 

The program shows records in descending order by the coefficient. 

Reference: Willet, Peter, John M. Barnard, and Geoffrey M. Downs. "Chemical Similarity 

Searching." J. Chem. Inf. Sci. 1998, 38, 983 996. 

3.7.2 Substructure Search 

If you want to search for a  general  structure, use the Query buttons to modify the drawn 

structure according to search criteria.  These buttons are located at the top of the left vertical 

toolbar in the ChemSketch window as A and Any.  Click the triangle on the lower right corner of 

the A and Any buttons to get all the query atoms and query bonds.  They allow you to do the 

following: 

Query Atoms 

Query Bonds 

ACD/I Lab via ChemSketch  

User's Guide 

22