The structure of the title Schiff base, C16H17N3O, displays a trans configuration with respect to the C=N double bond, with a dihedral angle of 14.98 (9)° between the benzene rings. In the crystal, mol-ecules are linked by N-H⋯O and C-H⋯O hydrogen-bonding inter-actions, giving sheets extending across the (001) plane. Hirshfeld surface analysis gave fingerprint plots showing enrichment ratios fo...

In the title compound, C(13)H(14)N(2)O, the N(pyrrole)-C(H(2))-C-C torsion angle is -7.7 (3)° and the dihedral angle between the pyrrole and benzene rings is 83.6 (2)°. In the crystal, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into chains extending along the c axis. We have previously reported another polymorphic form of this title compound, which has the same space group with di...

In the title mol-ecule, C(10)H(12)N(2)O, the dihedral angle between the benzene and imidazole rings is 14.86 (16)°. The approximately planar arrangement of the mol-ecule results in a distance of 2.54 Å between an ortho-H atom of the benzene ring and the double-bonded N atom of the imidazole ring. In the crystal structure, symmetry-related mol-ecules are linked by inter-molecular N-H⋯N hydrogen ...

Two rational primes p, q are called dual elliptic if there is an elliptic curve E mod p with q points. They were introduced as an interesting means for combining the strengths of the elliptic curve and cyclotomy primality proving algorithms. By extending to elliptic curves some notions of galois theory of rings used in the cyclotomy primality tests, one obtains a new algorithm which has heurist...

In the title compound, C(15)H(13)NO(3)S, the benzene ring and the five-membered heterocyclic ring are oriented at a dihedral angle of 12.00 (6)°. In the crystal, C-H⋯O inter-actions generate two types of cyclic motifs, R(2) (2)(14) and R(2) (2)(26), connecting the mol-ecules into tapes extending along [101]. In addition, there are π-π stacking inter-actions between the benzene and thio-phene ri...

In the title compound, C(18)H(12)Cl(2)N(2)O, the pyrazole ring is almost planar [r.m.s. deviation = 0.002 Å] while the two chloro-phenyl rings are twisted out from the plane of the pyrazole ring, making dihedral angles of 5.3 (1) and 65.34 (4)°. In the crystal, centrosymmetric R(2) (2)(24) dimers are formed about crystallographic inversion centres through a pair of C-H⋯Cl inter-actions. These d...

The destruction wrought by North Atlantic hurricanes in 2004 and 2005 dramatically emphasizes the need for better understanding of tropical cyclone activity apart from the records provided by meteorological data and historical documentation. We present a 220-year record of oxygen isotope values of alpha-cellulose in longleaf pine tree rings that preserves anomalously low isotope values in the l...

The crystal structure of the title compound, 2C(3)H(5)N(4)O(2) (+)·SO(4) (2-)·2H(2)O, displays a three-dimensional framework in which mixed infinite chains [oriented parallel to (510) and ([Formula: see text]10)] inter-fere, forming tunnels extending parallel to the c axis. Inter-molecular O-H⋯O, N-H⋯O and O-H⋯N hydrogen bonds ensure the unity of the structure and generate centrosymmetric R(4) ...

In the title compound, C(17)H(18)N(4)O(5)·2C(3)H(7)NO, two solvent mol-ecules are linked to the main mol-ecule via N-H⋯O and O-H⋯O hydrogen bonds, forming a hydrogen-bonded trimer. Intra-molecular O-H⋯N hydrogen bonds influence the mol-ecular conformation of the main mol-ecule, and the two benzene rings form a dihedral angle of 10.55 (18)°. In the crystal, inter-molecular O-H⋯O hydrogen bonds l...

In the title compound, C27H27NO5 (systematic name: 17-cyclopropylmethyl-14-hydroxy-6-oxo-4,5-epoxymorphin-an-6-yl benzoate), which is the benzoate ester of the opioid receptor antagonist naltrexone, the dihedral angle between the two phenyl rings is 77.1 (1)°. In the crystal, a weak aromatic C-H⋯Ocarbox-yl hydrogen bond involving the benzoate groups of adjacent mol-ecules gives rise to a chain ...