219915-20-5Relevant academic research and scientific papers
Synthesis and self-association of 4-pyrimidinones
Vaillancourt, Louis,Simard, Michel,Wuest, James D.
, p. 9746 - 9752 (2007/10/03)
Crystallization of 4-pyrimidinone from CHCl3 produced colorless needles that were shown by X-ray crystallography to consist of cyclic hydrogen- bonded dimers 2 of the 4(3H)-pyrimidinone tautomer 1. Vapor-pressure osmometry established that a simple derivative, 5-(2-phenylethyl)- 4(3H)pyrimidinone (5), self-associates in solution with a value of K(a) (220 ± 110 m-1 at 26 °C in CH2Cl2) close to that measured for 2-pyridinone under similar conditions. These observations suggest that 4-pyrimidinones and 2-pyridinones have similar modes and degrees of association and should be equally suitable for use as sticky functional groups that can be incorporated in complex molecules to make them associate in particular ways. This hypothesis was tested by synthesizing three dipyrimidinones (12, 16, and 21) designed to form strongly hydrogen-bonded dimers and by making a tetrapyrimidinone (26) designed to self-associate and to thereby generate a three-dimensional hydrogen-bonded network. In all cases, however, the compounds proved to have very low solubilities in organic solvents, and crystals suitable for X-ray diffraction could not be obtained despite intensive effort. It is possible that the simultaneous presence of multiple tautomers, all capable of strong intermolecular association, disfavors the sustained growth of single crystalline phases.
