At RHF, MPn, and DFT levels, a procedure of geometry optimization under the restrictions of pi-orbital interactions (GOR) was developed, thus providing a conjugated molecule with the following two types of localized reference geometries: a "GL" geometry where all double bonds are localized, and n different "GE-n" geometries, in each of which only two double bonds were permitted to conjugate. In...

In the title thia-zolidine-4-one derivative, C20H21NO6S, the central thia-zolidine ring is essentially planar (r.m.s. deviation for all non-H atoms = 0.0287 Å) and forms a dihedral angle of 88.25 (5)° with the meth-oxy-substituted benzene ring and 74.21 (4)° with the 1,3-benzodioxole ring. The heterocyclic ring (with two O atoms) fused to benzene ring adopts an envelope conformation with the no...

The title thia-calix[4]arene derivative, C(36)H(34)Br(2)O(8)S(4), adopts an unusual pinched cone conformation with the prop-oxy-substituted benzene rings inclined inward [forming a dihedral angle of 33.4 (1)°] and with the brominated benzene rings bent outward, making a dihedral angle of 66.1 (1)°. In the crystal, the mol-ecules form chains along [001] via C-H⋯S hydrogen bonds and S⋯S contacts ...

In the title compound, C(23)H(15)BrO(3), the anthracene ring system is essentially planar [maximum deviation = 0.29 (2) Å] and makes a dihedral angle of 5.74 (8)° with the mean plane of the bromo-substituted benzene ring. An intra-molecular C-H⋯O hydrogen bond generates an S(9) ring motif. In the crystal, mol-ecules are linked by C-H⋯O inter-actions, forming a two-dimensional network parallel t...

The asymmetric unit of the title compound, C(24)H(24)N(2)O(4), comprises two crystallographically independent mol-ecules A and B. The dihedral angles between the central dimethyl-substituted benzene ring and the two outer benzene rings are 49.5 (1) and 5.06 (11)° in mol-ecule A, and 42.55 (8) and 5.77 (9)° in mol-ecule B. In each mol-ecule, two strong intra-molecular O-H⋯N hydrogen bonds genera...

The mol-ecule of the title hydrazine derivative, C15H14N4O6, is essentially planar, the dihedral angle between the substituted benzene rings being 2.25 (9)°. The eth-oxy and hy-droxy groups are almost coplanar with their bound benzene ring [r.m.s. deviation = 0.0153 (2) Å for the ten non-H atoms]. Intra-molecular N-H⋯O and O-H⋯Oeth-oxy hydrogen bonds generate S(6) and S(5) ring motifs, respecti...

Silk cocoons, produced by Bombyx mori L. (Bombicidae) are used to treat heart palpitation, cough, asthma and catarrh. Phytochemical investigation of the cocoons led to the isolation of alkyl substituted dioxymethylene benzene derivatives and two citronellyl glucosides for the first time characterized as n-pentanyl-3,4-(dioxymethylene) benzene (1), n-pentanyl-2,3-dioxymethylene-4-hydroxybenzene ...

Abstract A capture reaction of hexadehydro-Diels–Alder (HDDA) derived benzyne with various substituted oxazoles is reported. With methyl, hydrogen, or phenyl as the substituent at 2-position oxazole, tetraynes afforded epoxyanthracene derivatives underwent dicarbonylation on benzene ring. The does not require any catalyst additive. mechanism behind was investigated. obtained polycyclic product ...