1,8-Naphthyridinecarbaldehydes and Their Methyl-Substituted Precursors: Synthesis, Molecular Structures, Supramolecular Motifs and Trapped Water Clusters

Article abstract of DOI:10.1002/ejoc.201701193

1,8-Naphthyridinecarbaldehydes bearing chlorine, pyrrolidinyl, piperidinyl or morpholinyl groups, were synthesised by oxidation of their methyl-substituted precursors. The prepared carbaldehydes represent valuable starting materials for the construction of systems that are useful for supramolecular and medicinal chemistry. Single-crystal X-ray diffraction studies of four carbaldehydes and six methyl derivatives provided interesting information about the supramolecular motifs in the crystal structures of solvent-free and solvated naphthyridines. The formation of interesting water clusters, for example, T4(2) water tape, was observed in the case of 7-methyl-2-(piperidin-1-yl)-1,8-naphthyridine as well as in the crystal structure of a by-product 7-(morpholin-1-yl)-1,8-naphthyridine-2-carboxylic acid. Knowledge of the detailed structural properties of water clusters is of great research interest to a broad range of scientific disciplines.