'compound space' is not a part of correct and usable English grammar.
There is no instance in which you would use the two words together to form this phrase.
When looking at the distributions in Figure 9 of the per-AID results, it is interesting to see, for a single conformer per compound anyway, that the per-AID average similarity distribution of NN pairs (primarily corresponding to the reputed "active/active" compound space) overlaps extensively with those of the NI pairs (essentially the reputed "active/inactive" compound space).
Overall, tandem mass spectral databases cover less than one per cent of the compound space that is covered in Chemspider or PubChem with 50 to 90 million compounds, respectively.
Third, despite the size of the commercial compound space, compounds containing some rather simple core fragments are lacking.
Assembling the focused kinase library where examples of specific structural classes were sought revealed gaps in commercial compound space.
In contrast, PubChem contains more than 48 million small molecule structures; the natural compound space is estimated to be larger than 250 000 compounds.
Even though our database contains 20,000 phytochemicals, this is still just a fraction of the natural compound space, which is estimated to be more than 150,000 compounds.
Recent activities in the construction, storage and exploration of very large virtual compound spaces are reviewed by this report.
As expected, the systematic exploration of compound spaces at the highest resolution (individual atoms and bonds) is intrinsically intractable.
Our server enables scientists to interactively browse chemical compound spaces by changing between different levels of structural detail while maintaining relationships between similar (neighbouring) compound classes.
Multiple search methods have been developed to perform searches (e.g. similarity, exact and substructure) into those compound spaces without the need for full enumeration.
By contrast, by staying within a finite number of reactions and a finite number of reactants or fragments, several virtual compound spaces have been constructed in a combinatorial fashion with sizes ranging from 1011 to 1020 compounds.
