2-Amino-4-(2-methoxy­phen­yl)-7,7-dimethyl-5-oxo-5,6,7,8-tetra­hydro-4H-chromene-3-carbonitrile and 2-amino-4-(2-methoxy­phen­yl)-7,7-dimethyl-3-nitro-4,6,7,8-tetra­hydro-5H-chromen-5-one hemihydrate

Calculations of the conformational preferences of the methoxy­phenyl substituent with respect to the pyran ring have been carried out for the two title compounds, C19H20N2O3, (II), and C18H20N2O5·0.5H2O, (III). In both mol­ecules, the heterocyclic ring adopts a flattened boat conformation and the fused cyclo­hexenone ring adopts a `sofa' conformation. The dihedral angles between these two flat fragments are 14.5 (1) and 9.3 (1)° in (II) and (III), respectively. In both mol­ecules, the methoxy group of the pseudo‐axial aryl substituent is syn with respect to the pyran ring. The dihedral angles between the 2‐methoxy­phenyl rings and the flat parts of the pyran rings are 86.3 (1) and 87.0 (1)°, respectively. In the crystal structure of (II), inter­molecular N—H⋯N and N—H⋯O hydrogen bonds link mol­ecules into a three‐dimensional framework. In the crystal structure of (III), a strong intra­molecular N—H⋯O hydrogen bond links the flat conjugated H—N—C=C—N—O fragment into a six‐membered ring. In (III), the water mol­ecule lies on a twofold axis and forms bifurcated O—H⋯O hydrogen bonds with the NO2 group of the mol­ecule. Also in (III), hydrogen bonds link the organic and water mol­ecules into infinite tapes along the c axis.