In the title mol-ecule, C(20)H(18)O(4), the three methyl groups of the tert-butyl substituent show rotational disorder. Each methyl group is split over three positions, with refined site-occupation factors of 0.711 (4), 0.146 (3) and 0.144 (4). The benzene ring of the benzoate group is oriented at a dihedral angle of 60.70 (7)° with respect to the planar chromene ring [maximum deviation = 0.046...

The phenyl ring in title mol-ecule, C(16)H(11)NO(3), forms a dihedral angle of 7.69 (6)° with the fused ring system. The observed conformation is stabilized by intra-molecular N-H⋯O and C-H⋯O inter-actions. In the crystal, supra-molecular chains are formed along the b axis which are mediated by π-π inter-actions [centroid-centroid distance = 3.614 (2) Å].

In title compound, C(16)H(9)ClO(4), the coumarin ring system is approximately planar [maximum deviation = 0.056 (1) Å] and is oriented with respect to the benzene ring at an angle of 22.60 (7)°. Inter-molecular C-H⋯O hydrogen bonding is present in the crystal.

In the title compound, [Zn(C(10)H(5)O(4))(2)(H(2)O)(2)], the Zn(II) atom lies on a crystallographic inversion center and is six-coordinated by two O atoms from water mol-ecules in the axial positions and four O atoms from two deprotonated coumarin-3-carb-oxy-late ligands in the equatorial plane, forming a slightly distorted octa-hedral coordination geometry. O-H⋯O hydrogen-bonding inter-actions...

In the title compound, C12H10O4, the dihedral angle between the coumarin ring system [maximum deviation = 0.033 (8) Å] and the propionate side chain is 78.48 (8)°. In the crystal, weak C-H⋯O hydrogen bonds generate inversion dimers and and C-H⋯π and π-π inter-actions link the dimers into a three-dimensional network. A quantum chemical calculation is in good agreement with the observed structure.

An efficient chiral squaramide-catalysed enantioselective Michael addition of pyrazolin-5-ones to 3-nitro-2H-chromenes for the synthesis of chiral heterocyclic systems containing both chroman and pyrazolone derivatives has been developed. This reaction afforded the desired products in high to excellent yields (up to 98%) with high enantioselectivities (up to 96%) and excellent diastereoselectiv...

The title compound {systematic name: 2-[7-fluoro-3,4-di-hydro-3-oxo-4-(prop-2-yn-1-yl)-2H-1,4-benzoxazin-6-yl]-4,5,6,7-tetra-hydro-1H-iso-indole-1,3(2H)-dione}, C19H15FN2O4, is a dicarboximide herbicide. The dihedral angle between the male-imide and benzene ring planes is 66.13 (5)°. In the crystal, C-H⋯O and C-H⋯F hydrogen bonds and weak C-H⋯π inter-actions [3.5601 (19) Å] link adjacent mol-ec...

A series of some new bisadducts possessing five, six membered and coumarin subunits were synthesized by the condensation of heterocyclic aldehydes with active methylene compounds and characterized by IR, NMR and X-ray crystallographic studies and were assayed as antitubercular agents. Among the bisadducts, 4-hydroxy-3-[(4-hydroxy-2-oxo-2H-3-chromenyl)(3-thienyl)methyl]-2H-2-chromenone 3a was fo...

The asymmetric unit of the title compound, C(14)H(17)N(3)O(3), contains two independent mol-ecules with different conformations of the ethyl groups. In the crystal, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into ribbons extending along the a axis.

The asymmetric unit of the title compound, C17H12O4, consists of two independent mol-ecules. The chromen-2-one ring and the 4-methyl-benzoate side chain are inclined to one another at a dihedral angle of 64.79 (10)° in one mol-ecule and 88.3 (1)° in the other. In the crystal, mol-ecules form R 2 (2)(8) centrosymmetric dimers via C-H⋯O hydrogen bonds. These dimers are stacked by C-H⋯O hydrogen b...