Crystal structures of 5,5 '-bis(hydroxymethyl)-3,3 '-biisoxazole and 4,4 ',5,5 '-tetrakis(hydroxymethyl)-3,3 '-biisoxazole

The molecular structure of 5,5'-bis(hydroxymethyl)-3,3'-biisoxazole, C8H8N2O4 (1), is composed of two trans planar isoxazole rings [r.m.s deviation = 0.006 (1) angstrom], each connected with a methyl hydroxyl group. Similarly, the structure of 4,40,5,5'-tetrakis(hydroxymethyl)-3,3'-biisoxazole, C10H12N2O6 (2), is composed of two planar isoxazole rings [r.m.s. deviation = 0.002 (1) angstrom], but with four hydroxymethyl groups as substituents. Both molecules sit on a center of inversion, thus Z' = 0.5. The crystal structures are stabilized by networks of O-H center dot center dot center dot N [for (1)] and O-H center dot center dot center dot O hydrogen-bonding interactions [for (2)], giving rise to corrugated supramolecular planes. The isoxazole rings are packed in a slip-stacked fashion, with centroid-to-centroiddistances of 4.0652 (1) angstrom for (1) (along the b-axis direction) and of 4.5379 (angstrom) for (2) (along the a-axis direction).