The title mol-ecule, C18H21Cl2NO3S2, contains one chiral carbon center and the absolute sterochemistry has been confirmed as as R. An intra-molecular N-H⋯O hydrogen bond occurs and the dihedral angle between the benzene rings is 64.5 (1)°. In the crystal, the mol-ecules are linked by weak C-H⋯O hydrogen bonds, forming a zigzag chain structure extending along the c-axis direction.

The title compound, C(14)H(11)NO(3), was isolated from the roots of Clausena wallichii. The carbazole ring system is approx-imately planar (r.m.s. deviation = 0.039 Å) and the dihedral angle between the two benzene rings is 4.63 (7)°. An intra-molecular O-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol-ecules are linked into a zigzag network extending parallel to the ac plan...

In the title compound, C(20)H(18)N(4)O(2), the dihedral angles between the central benzene ring and the pyridine rings are 57.55 (6) and 22.05 (8)°. The mol-ecular conformation is stabilized by intra-molecular N-H⋯N inter-actions and in the crystal structure an inter-molecular asymmetric cyclic hydrogen-bonding association involving both amide N-H donors and a common amide O-atom acceptor gives...

We give an explicit characterisation of pairs of orders in a quartic CM-field that admit the same polarised ideal class group structure. This generalises a simpler result for imaginary quadratic fields. We give applications to computing endomorphism rings of abelian surfaces over finite fields, and extending a completeness result of Murabayashi and Umegaki [13] to a list of abelian surfaces ove...

In the title compound, C(11)H(6)Cl(2)FN, the dichloro-benzene and the 2-fluoro-pyridine rings are oriented at a dihedral angle of 47.73 (3)°. In the crystal, pairs of C-H⋯N inter-actions link the mol-ecules into dimers with R(2) (2)(12) motifs. Mol-ecules are arranged in stacks extending along [100] via π-π inter-actions with a centroid-centroid distance of 3.8889 (3) Å.

In the racemic title compound, C(22)H(21)NO(3), the nitro-gen-containing ring of the pyran-oquinoline moiety adopts a slightly distorted half-chair conformation and the oxygen-containing ring adopts a slightly distorted chair conformation. The benzene rings make a dihedral angle of 84.97 (8)°. In the crystal, weak C-H⋯O inter-actions link the mol-ecules into chains extending along the a-axis di...

Let G be a finite group and let δ(G) be the number of prime order subgroups of G. We determine the groups G with the property δ(G) > |G|/2− 1, extending earlier work of C. T. C. Wall, and we use our classification to obtain new results on the generation of near-rings by units of prime order. 2000 Mathematics subject classification: primary 20D06; secondary 20D10, 16Y30.

In the title compound, C(17)H(16)O(6), the two methyl salicylate moieties are related by crystallographic twofold rotational symmetry with the two benzene rings close to being perpendicular [inter-ring dihedral angle = 86.6 (8)°]. Intra-molecular phenolic O-H⋯O hydrogen bonds with carboxyl O-atom acceptors are present, with these groups also involved in centrosymmetric cyclic inter-molecular O-...

The title compound, C(15)H(13)N(3)O(2)S, was synthesized by the reaction of 2-amino-5,6,7,8-tetra-hydro-4H-cyclo-hepta-[b]thio-phene-3-carbonitrile and o-fluoro-nitro-benzene. The dihedral angle between the thio-phene and nitro-phenyl rings is 75.15 (2)°. In the crystal, inter-molecular N-H⋯N and C-H⋯O inter-actions lead to the formation of a supra-molecular chain extending along the c-axis dir...

In the imidazolium cation of the title compound, C19H19N4O2(+)·Cl(-)·C3H7NO, the dihedral angles between the imidazole ring and the phenyl rings are 85.86 (4) and 70.26 (5)°. In the crystal, N-H⋯Cl hydrogen bonds link the imdiazo-lium cations and chloride anions into zigzag chains along [110] and together with C-H⋯Cl and C-H⋯O hydrogen bonds, which involve also the dimethyl-formamide solvent mo...