Search

A strategy of combining [3 + 2] cycloaddition and intramolecular Diels-Alder reaction is developed for the synthesis of a novel polycyclic scaffold with skeletal and substitutional diversities. Intermediates generated from stereoselective [3 + 2] cycloaddition of azomethine ylides and maleimides were derivatized for intramolecular Diels-Alder reaction of furan to form highly condensed heterocyclic products as racemic single diastereomers.

The nickel(II) complex of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide has been synthesized and characterized by Fourier transform-infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, and mass spectrometry (atmospheric pressure chemical ionization mass spectrometry). The single-crystal X-ray structures of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide (1) and bis[N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide]nickel(II) (2) have been determined from single-crystal X-ray diffraction data. Loss of the N–H proton resonance and the N–H stretching vibration and the shift of the νC=O and νC=S stretching vibrations confirm formation of the metal complex. These studies show that the metal complex is neutral in cis-configuration. The complex has been used as a single-source precursor for the deposition of nickel sulfide nanocrystals by thermolysis. The nickel sulfide nanocrystals were characterized by X-ray powder diffraction and transmission electron microscopy.

In the title compound, C14H10ClF2NO, the dihedral angle between the mean planes of the 4-chlorophenyl and 3,4-difluorophenyl rings is 65.2 (1)°. These two planes are twisted by 83.5 (5) and 38.9 (9)°, respectively, from that of the acetamide group. In the crystal, N—H...O hydrogen bonds form infinite chains along [100]. Weak C—H...O and C—H...F interactions are also observed and stack molecules along the b axis.

A multicomponent double [3 + 2] cycloaddition reaction of azomethine ylides has been developed for the synthesis of pyrrolidine-fused tetracyclic compounds. This reaction efficiently and stereoselectively generates six bonds and seven chiral centers in a one-pot reaction process.

In the title compound, C16H15FN2O, the dihedral angles between the benzene rings are74.7(8), 74.1 (1), 74.2 (7) and 74.3 (5)° in the four independent mol­ecules in the asymmetric unit. In the crystal, N—H—O hydrogen bonds involving the hydrazide and acetyl groups, which form R 2 2(18) ring motifs, link the mol­ecules into dimers, which form columns along [010].

In the title mol­ecule, C17H18N2O2, the benzene rings form a dihedral angle of 83.0 (7)°. In the crystal, N—H⋯O hydrogen bonds, in an R 2 2(8) graph-set motif, link mol­ecules into centrocymmetric dimers, and weak C—H⋯π inter­actions further link these dimers into columns in [100].

In the title compound, C8H9N3O3, the dihedral angle between the benzene ring and the acetohydrazide C—C(=O)—N—N plane [maximum deviation = 0.0471 (13) Å] is 87.62 (8)°. The nitro group is twisted by 19.3 (2)° with respect to the benzene ring. In the crystal, N—H...O hydrogen bonds link the molecules into a double-column structure along the b axis.

In the title compound, C16H13NOS, the central benzene ring makes dihedral angles of 3.25 (7) and 41.32 (8)°, respectively, with the thiazole and phenyl rings. In the crystal, O—H...N hydrogen bonds link the molecules into a chain along the c axis. A weak C—H...O interaction further connects the chains into a layer parallel to the ac plane.

In the title compound, C19H33NO, all three cyclohexane rings adopt chair conformations. The crystal packing features weak C—H...O interactions, forming a supramolecular chain along the c axis.

In the title compound, C(19)H(33)NO, all three cyclo-hexane rings adopt chair conformations. The crystal packing features weak C-H⋯O inter-actions, forming a supra-molecular chain along the c axis.

In the title compound, C19H20F2N2O, the six-membered piperazine group adopts a slightly distorted chair conformation. The dihedral angle between the mean planes of the two benzene rings is 73.4 (6)°. The mean plane of the ethanone group is twisted from the mean planes of the two benzene rings by 66.7 (8) and 86.2 (6)°. In the crystal, C—H...O and C—H...F interactions link the molecules, forming a three-dimensional structure.

In the phosphoric triamides N,N,N',N'-tetrabenzyl-N''-(2-chloro-2,2-difluoroacetyl)phosphoric triamide, C(30)H(29)ClF(2)N(3)O(2)P, (I), N,N,N',N'-tetrabenzyl-N''-(3-fluorobenzoyl)phosphoric triamide, C(35)H(33)FN(3)O(2)P, (II), and N,N,N',N'-tetrabenzyl-N''-(3,5-difluorobenzoyl)phosphoric triamide, C(35)H(32)F(2)N(3)O(2)P, (III), the tertiary N atoms of the dibenzylamido groups have sp(2) character with minimal deviation from planarity. The sums of the three bond angles about the N atoms in (I)-(III) deviate by less than 8° from the planar value of 360°. The geometries of the tertiary N atoms in all phosphoric triamides with C(O)NHP(O)[N](2) skeletons deposited in the Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B58, 380-388] have been examined and the bond-angle sums at the two tertiary N atoms (SUM1 and SUM2) and the parameter ΔSUM (= SUM1 - SUM2) considered. It was found that in compounds with a considerable ΔSUM value, the more pyramidal N atoms are usually oriented so that the corresponding lone electron pair is anti with respect to the P=O group. In (I), (II) and (III), the phosphoryl and carbonyl groups, separated by an N atom, are anti with respect to each other. In the C(O)NHP(O) fragment of (I)-(III), the P-N bond is longer and the O-P-N angle is contracted compared with the other two P-N bonds and the O-P-N angles in the molecules. These effects are also seen in analogous compounds deposited in the CSD. Compounds with [C(O)NH]P(O)[N]X (X ≠ N), such as compounds with a [C(O)NH]P(O)[N][O] skeleton, have not been considered here. Also, compounds with a [C(O)NH](2)P(O)[N] fragment have not been reported to date. In the crystal structures of all three title compounds, adjacent molecules are linked via pairs of P=O···H-N hydrogen bonds, forming dimers with C(i) symmetry.

In the title compound, C15H10ClNO3, a substituted chalcone, the dihedral angle between the benzene rings is 5.1 (7)°. The nitro group makes a dihedral angle of 12.5 (3)° with the benzene ring to which it is attached. In the crystal, weak C—H⋯O inter­actions link the mol­ecules into a one-dimensional array along [010]. The crystal studied was an inversion twin, with a refined ratio for the twin components of 0.6060 (9):0.3939 (1).

In the crystal structure of the title compound, [Cu(2)Br(2)(C(9)H(14)N(2)S)(2)], the mol-ecule resides about a crystallographic inversion center. The coordination sphere around each copper ion has a distorted tetra-hedral geometry, with ligation by two bridging bromide ions, an amine N atom and an imine N atom. The thio-phene ring is disordered over two sites, with occupancies of 0.719 (3) and 0.281 (3). Weak C-H⋯π inter-actions feature in the crystal packing.

The title compound, C30H26O4, contains an oxo-cyclohexane ring in a distorted half-chair configuration, with disorder of two C atoms in a 0.859 (4):0.141 (4) ratio. The dihedral angle between the mean planes of the two napthalene ring systems is 58.6 (8)°.

In the title molecule, C20H16O2, the dihedral angle between the phenyl rings of the diphenylmethyl group is 68.3 (2)°. The benzoate group is essentially planar, with a maximum deviation of 0.017 (2) Å for the carbonyl O atom, and the two phenyl rings are twisted by 27.5 (4) and 85.6 (9)° from this plane. In the crystal, weak C—H...O hydrogen bonds link molecules along [100].

In the title mol-ecule, C(16)H(17)ClF(2)N(3)O(2)P, the N-H unit of the C(=O)NHP(=O) fragment adopts a syn orientation with respect to the P=O group. The two F atoms and the Cl atom of the ClF(2)C group are disordered over two sets of sites with refined occupancies of 0.605 (6) and 0.395 (6). In the crystal, mol-ecules are linked via N-H⋯O=C hydrogen bonds the and the (N-H⋯)(N-H⋯)O=P group into chains along [010].

In the title molecule, C7H7N3S2, the dihedral angle between the thiophene and thiadiazole rings is 72.99 (5)°; the two rings are oriented so that the S atoms in each ring are on the same side. In the crystal, the three-dimensional network involves strong N—H...O hydrogen bonds, as well as C—H...π and π–π stacking interactions [centroid–centroid distances = 3.654 (1) and 3.495 (1) Å].

A multicomponent double [3 + 2] cycloaddition reaction of azomethine ylides has been developed for the synthesis of pyrrolidine-fused tetracyclic compounds. This reaction efficiently and stereoselectively generates six bonds and seven chiral centers in a one-pot reaction process.