for a fixed positive integer , we say a ring with identity is n-generalized right principally quasi-baer, if for any principal right ideal of , the right annihilator of is generated by an idempotent. this class of rings includes the right principally quasi-baer rings and hence all prime rings. a certain n-generalized principally quasi-baer subring of the matrix ring are studied, and connections...

The title compound, C(22)H(22)O(5), crystallizes with two independent mol-ecules in the asymmetric unit, both of which possess pseudo-C(s) symmetry. The central 1,3-dioxanone rings have envelope conformations, with the C atom bearing the two methyl groups at the flap. The benzene rings of the meth-oxy-benzyl-idene units, attached in the 4- and 6-positions on the central 1,3-dioxanone rings, are...

The central residue in the title compound, C(21)H(21)N(3)O(3), is close to planar (r.m.s. deviation = 0.0753 Å for all non-H atoms from OH to NH inclusive): the hy-droxy, amino and carbonyl groups all lie to the same side of the mol-ecule (the conformation about the ethene bond is Z), facilitating the formation of intra-molecular O-H⋯O and N-H⋯O hydrogen bonds that close S(6) rings. However, ov...

The title compound, C27H26O3, crystallized with two independent mol-ecules (A and B) in the asymmetric unit. In mol-ecule A, the plane of the central benzene ring forms dihedral angles of 75.78 (14) and 52.75 (16)° with that of the terminal benzene rings, and the dihedral angle between the planes of the terminal benzene rings is 51.49 (17)°. The corresponding values for mol-ecule B are 75.18 (1...

In the title compound, C14H17N3OS2, the central piperidinone ring adopts a chair conformation and the thia-zole rings are inclined to its mean plane by 80.16 (12) and 67.15 (12)°. The O atom and methyl group C atom deviate significantly from the mean plane of the central piperidinone ring, by 0.8138 (2) and 0.3175 (2) Å, respectively. The dihedral angle between the thia-zole rings is 51.88 (13)...

In the title solvate, C22H18O6·2C3H7NO, the complete dicarboxylic acid molecule is generated by a crystallographic twofold axis, which bisects the central benzene ring and one N,N-di-methyl-formamide solvent mol-ecule. The dihedral angle between the central and pendant benzene rings is 54.53 (5)° while that between the pendant rings is 45.44 (5)°. In the crystal, the acid molecules are linked t...

In the title compound, C(24)H(28)N(2)O(4)S(2), the dihedral angles between the central benzene ring and the pendant rings are 77.44 (11) and 79.23 (10)°, and the dihedral angle between the pendant rings is 23.31 (12)°. Both sulfonamide groups project to the same side of the central benzene ring and the mol-ecule has approximate non-crystallographic mirror symmetry. One of the ethyl side chains ...

This work presents a metaheuristic approach to solve the Capacitated m-Ring Star Problem (CmRSP), a problem introduced by Baldacci et al. [1] which models the design of telecommunication networks with survivability properties. The CmRSP consists of finding a set of m cycles (rings), each of them including the central depot (the central telephone office), a subset of customers, and a set of opti...

In the title benzyl-idenemalono-nitrile derivative, C17H12N2O, the dihedral angles between the central benzene ring and the Y-shaped C=C(CN)2 group (r.m.s. deviation = 0.006 Å) and the terminal benzene ring are 12.72 (8) and 37.60 (11)°, respectively. The Car-O-Csp (3)-Car torsion angle is -174.52 (13)° and the major twist between the aromatic rings occurs about the Csp (3)-Car bond. Weak aroma...

In the mol-ecule of the title compound, C(21)H(19)NO, the terminal saturated six-membered ring of the dihydro-acridine unit adopts an envelope conformation, while the other two fused rings are nearly coplanar, with a dihedral angle of 2.61 (3)°. The coplanar ring system is oriented with respect to the phenyl ring at a dihedral angle of 74.58 (3)°. In the crystal structure, there is a C-H⋯π cont...