Synthesis and X-ray structural investigations of 2-amino-7-methyl-4-(1-naphthyl)-5-oxo4H,5H-pyrano[4,3-b]pyran-3-carbonitrile and 2-amino-4-(1-naphthyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile

摘要

Synthesis and X-ray structural investigations have been carried out for the two title compounds C20H14N2O3 (4) and C(23)H(14)N(2)O(3)center dot C2H3N (5). Compound 4 crystallizes in the monoclinic space group P2(1), with a = 7.0542(5), b = 8.822(1), c = 24.833(2) angstrom, beta = 94.30(4)degrees, V = 1541.0(4) angstrom(3), and Z = 4. Compound 5 crystallizes with an acetonitrile solvent molecule in the monoclinic space group P2(1), with a = 11.075(1), b = 7.854(1), c = 22.703(2) angstrom, beta = 90.67(1)degrees, V = 1974.5(3) angstrom(3), and Z = 4. In both molecules, the 4H-pyran ring adopts a flattened-boat conformation. The naphthalene substituent occupies a pseudo-axial position and the dihedral angle with the flat part of the pyran ring is equal to 94.6(3) in 4 and 76.8(3)degrees in 5. The mutual orientation of these fragments and the flatness of the heterocyclic rings lead to H center dot center dot center dot H intramolecular steric interactions: H4A center dot center dot center dot H18A 1.98 angstrom in 4 and 2.11 angstrom in 5. In the crystal of 4, intermolecular hydrogen bonds N-H center dot center dot center dot O and C-H center dot center dot center dot N link molecules into infinite tapes along the b axis. In the crystals of 5, intermolecular hydrogen bonds N-H center dot center dot center dot O and C-H center dot center dot center dot N link molecules into infinite layers parallel to the bc plane. In each case, the C-H center dot center dot center dot N interaction can be considered to be a weak hydrogen bond. The acetonitrile molecules link via intermolecular weak C-H center dot center dot center dot N hydrogen bonds to form infinite chains along the b axes.