title: 4-Oxo-N-phenyl-4H-chromene-2-carboxamide and of a new polymorph of 7-methoxy-4-oxo-N-p-tolyl-4H-chromene-2-carboxamide and its hemihydrate.
abstract: 4-Oxo-N-phenyl-4H-chromene-2-carboxamide, C16H11NO3, crystallizes in the space group P2(1)/n and its derivative 7-methoxy-4-oxo-N-p-tolyl-4H-chromene-2-carboxamide, C18H15NO4, forms two polymorphs which crystallize in the space groups P2(1)/c and P1. The structures have an anti-rotamer conformation about the C-N bond; however, the amide O atom can be either trans- or cis-related to the O atom of the pyran ring. The latter compound also crystallizes as a hemihydrate, C18H15NO4·0.5H2O, in the space group C2/c. This compound has a similar structure to that of the unsolvated compound.
authors: CIQ/Departamento de Quιmica e Bioquιmica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal.
authors: Joana
authors: J
authors: Reis
authors: Alexandra
authors: A
authors: Gaspar
authors: Fernanda
authors: F
authors: Borges
authors: Ligia R
authors: LR
authors: Gomes
authors: John Nicolson
authors: JN
authors: Low
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D015394:Molecular Structure; D014050:Toluene / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: C587651:4-Oxo-N-phenyl-4H-chromene-2-carboxamide; C587654:7-methoxy-4-oxo-N-p-tolyl-4H-chromene-2-carboxamide; D001578:Benzopyrans; D014050:Toluene
keywords: chromones; conformation; crystal structure; drug design; supramolecular structure