Crystal structures of two 4-chromene derivatives: 2-amino-3-cyano-4-(3,4-di-chloro-phen-yl)-7-hy-droxy-4-benzo[1,2-]pyran 1,4-dioxane monosolvate and 2-amino-3-cyano-4-(2,6-di-chloro-phen-yl)-7-hy-droxy-4-benzo[1,2-]pyran.

In the title compounds, CHClNO·CHO and CHClNO, the bicyclic 4-chromene cores are nearly planar with maximum deviations of 0.081 (2) and 0.087 (2) Å.

Crystal structure of (E)-4-(acet-oxy-imino)-N-allyl-3-isopropyl-2,6-di-phenyl-piperi-dine-1-carbo-thio-amide.

The title compound, C26H31N3O2S, crystallizes with two mol-ecules (A and B) in the asymmetric unit. In each case, the piperidine ring exists in a twist-boat conformation. The dihedral angle between the phenyl rings is 46.

Crystal structure of isobutyl 4-(2-chloro-phen-yl)-5-cyano-6-{(E)-[(di-methyl-amino)-methyl-idene]amino}-2-methyl-4H-pyran-3-carboxyl-ate.

In the title compound, C21H24ClN3O3, the dihedral angle between the pyran ring (r.m.s.

(E)-3-Methyl-2,6-di-phenyl-piperidin-4-one O-(3-methyl-benzo-yl)oxime.

In the title compound, C26H26N2O2, the piperidine ring exhibits a chair conformation. The phenyl rings are attached to the central heterocycle in an equatorial position. The dihedral angle between the planes of the phenyl rings is 57.

Methyl ({[(4E)-1,3-dimethyl-2,6-di-phenyl-piperidin-4-yl-idene]amino}-oxy)acetate.

In the title compound, C22H26N2O3, the piperidine ring exhibits a chair conformation. The phenyl rings attached to the piperidine at the 2- and 6-positions have axial orientations. These rings make a dihedral angle of 49.