Molecular Pharmaceutics 2007-01-01

Co-crystals of caffeine and hydroxy-2-naphthoic acids: unusual formation of the carboxylic acid dimer in the presence of a heterosynthon.

Dejan-Kresimir Bucar, Rodger F Henry, Xiaochun Lou, Richard W Duerst, Thomas B Borchardt, Leonard R MacGillivray, Geoff G Z Zhang

Index: Mol. Pharm. 4(3) , 339-46, (2007)

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Abstract

A group of caffeine-containing co-crystals of hydroxy-2-naphthoic acids were synthesized and analyzed via single-crystal X-ray diffraction and IR analysis. The imidazole-carboxylic acid synthon was observed in co-crystals involving 1-hydroxy-2-naphthoic and 3-hydroxy-2-naphthoic acid. In the case of 6-hydroxy-2-naphthoic acid, the co-crystal exhibits a hydrogen-bonded carboxylic acid dimer in the presence of a hydroxyl-caffeine heterosynthon.