Exclusion criteria for the Maybridge screening collection database

Reactive molecules have been excluded from the database in order to reduce the number of false positives or potential “false leads.” Specifically, compounds that contain the following chemical moieties have been excluded to produce a set of chemical structures that have the maximum diversity and drug-like properties. This is designed to result in a higher percentage of genuine leads for optimization and eliminate the time and money expended on following unsuitable hits. The excluded chemical moieties have been carefully selected from data and other information sources used to develop the Maybridge collection since the early 1990s, when high-throughput screening came to the forefront of lead identification. These data and our own experience of over 50 years ensure that this database will be an ideal candidate for use in high-throughput screening programs.

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Excluded chemical moieties:

Chemical moiety Reasoning
Acyl halides Covalent bonding
Sulphonyl halides Covalent bonding
Isocyanates Covalent bonding
Isothiocyanates Covalent bonding
Activated halides1 Covalent bonding
Anhydrides Covalent bonding
Aldehydes (incl. aminoformyl moieties) Covalent bonding
Hydrazines Covalent bonding
Azides Toxicity
Diazonium salts Toxicity
Quaternary salts (incl. N-oxides) Toxicity
Nitrosos Toxicity
Aziridines2 Toxicity/covalent bonding
Epoxides Covalent bonding
Thiols3 Toxicity/covalent bonding
Disulfides Toxicity/covalent bonding
Picrates Toxicity
Perchlorates (Periodates) Toxicity
Simple anilines and phenols Toxicity
1,2-dicarbonyls4 Toxicity
Vinyl ketones (Michael acceptors)5 Covalent bonding
Nitro groups (max. of 2)6 Toxicity/solubility
Halo atoms (max. of 5) Toxicity
Metals7 Toxicity
Simple molecules Simple
MW <150 Simple

1Compounds classified as activated halides consist of the 4 following moieties: a) halide with a NO2 ortho to the halide, e.g., 2-chloronitrobenzene, b) halide with a NO2 para to the halide, e.g., 4-chloronitrobenzene, c) halide with a hetero ring N ortho to the halide, e.g., 2-chloropyridine, and d) halide with a hetero ring N para to the halide, e.g., 4-chloropyridine (where N activation may be of some significance in some screening programs).

2Aziridines which have a free NH moiety on the aziridine ring.

3Thiols where the thiol moiety cannot exist as the thione, i.e., benzene thiol excluded, but 1,2,4-triazole-3-thione included.

4Chain dicarbonyls are excluded, ring dicarbonyls are included, i.e., glyoxalates excluded, ring-substituted isatin moieties included.

5Vinyl ketones moieties have been excluded where the vinyl ketone is directly attached to a ring system and the other end of the moiety has not been substituted, i.e. cinnamic acid, simple ester, amide nitrile, etc. would be excluded. Where a cinnamoyl chloride has been reacted with a R-NH2, these would be included. Compounds of type ring-COCH=CH-ring (chalcones) are excluded. For further information on this exclusion criteria, please contact us.

6Halo atoms maximum 5. When calculating this, exclusion salts are not included and a trifluoromethyl group is taken as only 1 halo. All trichlorovinyl moieties have been excluded.

7Metals, sodium, and potassium salts of acids are included. Compounds excluded from the Maybridge screening collection for any of the above reasons are still held by the Maybridge compounds team. For customers requiring a database of these compounds, please contact us.

Examples of excluded chemical structures

The figure below shows examples of chemical structures excluded from the screening library. 

Examples of chemical structures excluded from Maybridge Screening Collection
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