The collection, curation and modeling of Open Melting Point measurements August 26, th Meeting on U.S. Government Chemical Databases and Open Chemistry Jean-Claude Bradley Department of Chemistry Drexel University Andrew Lang Department of Mathematics Oral Roberts University Antony Williams ChemSpider Royal Society of Chemistry
The Problem of Data Quality in Chemistry Lack of provenance Reliance on a system of “trusted sources” CRC Handbook Merck Index Chemical Vendor Catalogs (e.g. Sigma-Aldrich) Peer-Reviewed Journals In the case of melting points:
Strategy for the curation of melting points Using technology, we can begin to replace the “trusted source” model with one based on transparency and provenance 1.Rely on redundancy when possible 2.Provide the maximum level of provenance when necessary (Open Notebook Science) 3.Adhere to Open Data, Open Descriptors and Open Algorithms for measurements and modeling
The Chemical Information Validation Sheet 567 curated and referenced measurements from Fall 2010 Chemical Information Retrieval course
Investigating the m.p. inconsistencies of EGCG
Most popular data sources
Alfa Aesar donates melting points to the public
Open Melting Point Explorer
Outliers MDPI dataset EPA/PhysProp (donated all data to public also)
Outliers for ethanol: Alfa Aesar and Oxford MSDS
Inconsistencies and SMILES problems within MDPI dataset
MDPI Dataset labeled with High Trust Level
EPA/PHYSPROP Structure Errors (Incorrect Valence): 2315 out of were contained pentavalent nitrogens
EPA/PHYSPROP Errors: Structure displayed is for the neutral compound dopamine but the associated CAS Number and chemical name in the file are for the hydrobromide salt.
Common errors in datasets 1.multiple melting points for the same compound in the same database 2.stereochemistry issues 3.sign inversion 4.conversion errors (Kelvin/Celcius Fahrenheit/Celcius) 5.bad SMILES (non-rendering) 6.salts associated with SMILES for free base 7.using boiling point for melting point
Open melting point datasets Double+ validated: 2706 compounds (7413 highly curated measurements. range: C. Compounds that had at least one chiral center, possessed cis/trans isomerism, were inorganic or a salt removed.) Entire dataset: unique compounds (27684 measurements – no inorganics or salts)
Open Models with Open Data Using Open Descriptors (CDK)
Modeling Results ModelTraining setTest set (TS) DescriptorsTS AAETS RMSETS R D D/3D D D
Melting point prediction service
Melting point predictions and measurements on iPhone/iPad (Alex Clark)
Publication of double+ validated melting point dataset to Nature Precedings and LuLu
For all Formats of ONS Projects
Open Melting Point Datasets Currently 20,000 compounds with Open MPs
Some melting points can’t be resolved only with literature: 4-benzyltoluene
Motivation: Faster Science, Better Science
Open Lab Notebook page measuring the melting point of 4-benzyltoluene
Using melting point for temperature dependent solubility prediction
Crowdsourcing Solubility Data
Integration of Multiple Web Services to Recommend Solvents for Reactions
All ONS web services
Google Apps Scripts web services
Google Apps Scripts for conveniently exploring melting point data
Straight chain carboxylic acids from 1 to 10 carbons Straight chain alcohols from 1 to 10 carbons Comparison of model with triple validated measurements
Cyclic primary amines from 3 to 6 carbons (cyclobutylamine flagged for validation – only single source available)
Google Apps Scripts for planning reactions and creating schemes
Open Melting Points in Supplementary Data Pages of Wikipedia (Martin Walker)
Conclusions For science to progress quickly there is great benefit in moving away from a “trusted source” model to one based on transparency and data provenance Open Notebook Science offers an efficient way to make research transparent and discoverable