The title compound, C(23)H(20)N(2)O(7), consists of three fused six-membered rings (A, B and C) and one five-membered ring (D), linked to two ethyl acetate groups. The four fused rings are slightly folded around the O=C⋯C=O direction of the anthraquinone system, with a dihedral angle of 3.07 (8)° between the fused five- and six-membered rings (C and D) and the terminal ring (A). The planes thro...

Polycyclic aromatic hydrocarbons (PAHs) in which five-membered rings have been interspersed among the six-membered rings generally display curved p systems that can be either fully closed (fullerenes) or partially open (bowl-shaped fullerene fragments), depending on the number of five-membered rings. Both classes of compounds belong to the larger family we call ‘GEODESIC POLYARENES.’ Herein, we...

In the title compound, C(18)H(26)O(3)S(8), the two five-membered rings exhibit envelope conformations. The two S atoms in the 17-membered macrocycle deviate from the plane of the fused five-membered ring by 1.429 (3) and -1.434 (3) Å in opposite directions.

In the title mol-ecule, C(20)H(26)O(3), a clerodane diterpenoid isolated from Dodonaea viscosa-, the trans-fused six-membered rings of the deca-line system display chair conformations. The five-membered lactone ring adopts an envelope conformation and the five-membered furan ring is essentially planar with a maximum deviation of 0.0052 (12) Å.

The mol-ecular structure of the title compound, C(28)H(20)N(4)O(6), consists of three fused six-membered rings (A,B,C) and one five-membered ring (D). The latter is linked to an isoxazole ring (E) via a methyl-ene unit. A 4-nitro-phenyl substituent (F) is attached to the isoxazole. The fused five and six-membered rings (C,D) are almost coplanar with an r.m.s. deviation of 0.0345 Å and make a di...

In the title compound, C21H15FN2O2, the furan ring has a flattened half-chair conformation [the methine C atom lies 0.136 (2) Å above the C5 plane which has an r.m.s. deviation of 0.0229 Å]. Overall, the 1H-benzo[f]chromene fused-ring system approximates a plane (r.m.s. deviation of the 14 non-H atoms = 0.049 Å). The fluoro-benzene ring is almost perpendicular to this plane [dihedral angle = 89...

A series of 18-membered macrocyclic complexes of metal Ni(II) of the type [M(H2Cy )] have been synthesized and characterized on the basis of spectral, magnetic and conductivity studies. The macrocyclic ligands H 4 Cy1-4 (Fig. 1) are tetrabasic having four imido hydrogen but behave in a dibasic manner. Out of eight nitrogens, four imido and four imino, ligands utilize four imido nitrogens for sq...

The title compound, C34H38ClN5O2, has spiro links connecting the pyrrolidine ring and indole residue, as well as the piperidine and pyrrolidine rings. A half-chair conformation is found for the piperidine ring with the C atom connected to the spiro-C atom lying 0.738 (4) Å out of the plane of the remaining five atoms (r.m.s. deviation = 0.0407 Å). The methyl-ene C atom is the flap in the envelo...

We suggest four new benzene dimers, (C(6)H(6))(2), all featuring one or more cyclohexadiene rings trans-fused to 4- or 6-membered rings. These hypothetical dimers are 50-99 kcal/mol less stable than two benzenes, but have computed activation energies to fragmentation ≥27 kcal/mol. A thorough search of potential escape routes was undertaken, through cyclobutane ring cleavage to 12-annulenes, sig...

In the title compound, C(15)H(16)BrNO(3)S, the boat form of the six-membered ring is almost symmetrical with respect to the ep-oxy bridge. The two five-membered rings generated by the ep-oxy bridge of the six-membered ring adopt envelope conformations, whereas the N-containing five-membered ring adopts a twisted conformation. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds.