Volume 2 Chapter 7 Numeric Sub-menu *CELA *CELB AND *CELC
*CLASS is used to test for entries having a specified chemical class number or numbers.
CSD Contents
Following changes made in October 1997, there are now just 11 chemical class numbers:
| Chemical Class | Old Number(s) | New Number | |||||||||||||||||||||||||||||||||
| Carbohydrates | 45 | 1 | |||||||||||||||||||||||||||||||||
| Nucleosides & nucleotides | 47 | 2 | |||||||||||||||||||||||||||||||||
| Amino-acids, peptides and complexes | 48, 82 | 3 | |||||||||||||||||||||||||||||||||
| Porphyrins, corrins & complexes | 49 | 4 | |||||||||||||||||||||||||||||||||
| Antibiotics | 50 | 5 | |||||||||||||||||||||||||||||||||
| Steroids | 51 | 6 | |||||||||||||||||||||||||||||||||
| Terpenes | 52-57 | 7 | |||||||||||||||||||||||||||||||||
| Alkaloids | 58 | 8 | |||||||||||||||||||||||||||||||||
| Miscellaneous natural products | 59 | 9 | |||||||||||||||||||||||||||||||||
| Supramolecular entities | 60, 61 | 10 | |||||||||||||||||||||||||||||||||
| High polymers | 11 |
An entry can be assigned up to four class numbers so, for example, a steroidal alkaloid would belong to class 6 and class 8.
Graphics QUEST3D Procedure
Select *CLASS from the NUMERIC sub-menu and respond to the standard numeric prompts.
Basic QUEST Procedure
Ex.
T1 *CLAS .EQ. 8
This will register hits for all alkaloids, steroidal alkaloids, etc.
This is an ideal use of chemical class searching since alkaloids exhibit such a great variety of chemical connectivities.
Related Bit Screens
As a result of the changes made in October 1997:
Bit screen 136 (chemical classification field present) is no longer used.
Bit screen 57 (entry is an "organic" compound class 1-65 or 70) is now set to 1 if the compound does not contain any of TR, LN, AN, Al, Ga, In, Tl, Ge, Sn, Pb, Sb, Bi or Po.
