Johannes H. van Tonder

Nano CuFe2O4: an efficient, magnetically separable catalyst for transesterification of β-ketoesters

The preparation of a variety of β-ketoesters was achieved in high yields from methyl acetoacetate under neutral conditions through the utilization of magnetic CuFe2O4 nanoparticles as catalyst. Recycling of the catalyst was performed up to eight times without significant loss in activity. The catalyst was characterized using XRD, XPS, SEM and TEM techniques.

2',3,4,4'-Tetra-meth-oxy-chalcone.

In the title compound [systematic name: 1-(2,4-dimethoxyphenyl)-3-(3,4-dimethoxyphenyl)prop-2-en-1-one], C19H20O5, the dihedral angle between the benzene rings is 26.88 (5)°. One of the methoxy groups is twisted slightly away from the plane [C—O—C—C torsion angle = −12.8 (3)°] while the others are almost co-planer [C—O—C—C torsion angles = −3.2 (3), 2.6 (3) and −3.6 (3)°]. The crystal packing is stabilized by intermolecular C—H⋯O interactions. A weak intramolecular C—H⋯O interaction occurs.

The crystal structure of 6-(4-bromobenzyl)-1,3,5-trimethyl-7-phenyl-1,5-dihydro-2H-pyrrolo[3,2-d]pyrimidine-2,4(3H)-dione, C22H20BrN3O2

Abstract C22H20BrN3O2, monoclinic, P21/c (no. 14), a = 15.889(12) Å, b = 16.332(13) Å, c = 7.324(5) Å, β = 94.985(5), V = 1893(2) Å3, Z = 4, Rgt(F) = 0.0295, wRref(F2) = 0.0790, T = 100(2) K.

Racemic tricarbonyl[(4a,5,6,7,8,8a-η)-2-phenyl-3,4-dihydro-2H-1-benzopyran]chromium(0)

The title compound, [Cr(C15H14O)(CO)3], displays a distorted envelope configuration of the dihydropyrane ring. The dihedral angle between the phenyl and phenylene rings is 50.63 (4)°. The Cr0 atom is coordinated by three CO groups and the phenylene ring of the flavan ligand in an η6 mode, with a common arene-to-metal distance

Racemic tricarbon­yl(η6-7-meth­oxy­flavan)chromium(0)

In the title compound [systematic name: tricarbonyl(η6-7-methoxy-2-phenyl-3,4-dihydro-2H-1-benzopyran)chromium(0)], [Cr(C16H16O2)(CO)3], the Cr(CO)3 unit is coordinated by the phenylene ring of the flavan ligand, exhibiting a three-legged piano-stool conformation, with a point to plane distance of 1.750 (1) Å. The phenyl ring is twisted away from the fused ring system by 36.49 (5)° (r.m.s. deviation = 0.027 Å; fitted atoms are the C6 ring and the attached fused-ring C and O atoms). The dihydropyran ring displays a distorted envelope configuration by displacement of the phenyl-bearing and the adjacent ring C atoms from the fused-ring system plane by 0.356 (2) and 0.402 (2) Å, respectively.

2',3,4,4',5-Penta-meth-oxy-chalcone.

In the title chalcone [systemetic name 1-(2,4-dimethoxyphenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one], C20H22O6, the dihedral angle between the plane of the two benzene rings is 7.03 (4)° with all but one of the methoxy groups essentially co-planar with these rings [C—C—O—C torsion angles = −76.1 (2), −0.7 (3), 1.8 (3), −6.2 (3), 2.0 (3)°]. An intramolecular C—H⋯O interaction occurs. The crystal packing is stabilized by weak intermolecular C—H⋯O hydrogen bonds.

Tricarbon­yl(η6-flavone)chromium(0)

In the title compound, [Cr(C15H10O2)(CO)3], the Cr(CO)3 unit exhibits a three-legged piano-stool conformation. The chromium metal centre is coordinated by the phenyl ring of the flavone ligand [Cr—(phenyl centroid) distance = 1.709 (1) Å]. The ligand is approximately planar, the dihedral angles between the γ-pyrone ring and the phenyl ring and between the γ-pyrone and the phenylene ring being 2.91 (5) and 3.90 (5)°, respectively. The molecular packing shows π–π stacking between the flavone ligands of neighbouring molecules.

The crystal structure of 6-chloro-2,4-diphenylquinoline

Abstract C21H14ClN, orthorhombic, Pca21 (No. 29), a = 7.6860(5) Å, b = 10.1610(5) Å, c = 19.8990(5) Å, V = 1554.1(13) Å3, Z = 4, Rgt(F) = 0.0318, wRref(F2) = 0.0783, T = 100(2) K.

Crystal structure of 2,3-dicyano-1,4-phenylene bis(trifluoromethanesulfonate), C10H2F6N2O6S2

C10H2F6N2O6S2, orthorhombic, P212121 (no. 19), a = 8.1480(10) Å, b = 11.5550(15) Å, c = 16.178(2) Å, V = 1523.2 Å, Z = 4, Rgt(F) = 0.0390, wRref(F ) = 0.1081, T = 300 K.

2,5-Dihexyl­thio­phene 1,1-dioxide

In the title molecule, C16H28O2S, the two n-hexyl groups are in all-trans conformations. Their C atoms are situated close to the plane of the thiophene ring with a maximum deviation of 0.718 (6) Å for one of the terminal methyl groups. In the crystal, a short C—H⋯O contact is observed between thiophene 1,1-dioxide groups.