Crystal Structure Prediction of a Co-Crystal Using a Supramolecular Synthon Approach: 2-Methylbenzoic Acid-2-Amino-4-methylpyrimidine

The crystal structure prediction (CSP) of the 1: 1 binary crystal of 2-methylbenzoic acid and 2-amino-4-methylpyrimidine was performed in the recently held fourth blind test (organized by the Cambridge Crystallographic Data Centre) using a supramolecular synthon based approach. Further work was done on this system after the blind test was concluded. A combined quantum mechanical and Cambridge Structural Database (CSD) study of the individual components was carried out to assess the viability of possible synthons both energetically and statistically. CSP of a few selected co-crystals from the CSD and from our own in-house experimental database was carried out in order to standardize the methodology for the prediction of the crystal structure of the target compound. The CSP of the co-crystal was accomplished successfully showing the applicability of a synthon based approach to CSP for this category of substance, especially with a combination of computational and experimental techniques.