The electronic structure and stability of M?@Mn systems is considered using DFT. metal atom M? a rare earth, actinide, or d transition metal, M coinage (Group 11) metal. ? aromaticity along the Mn ring emphasized. As further indicator for it, magnetically induced currents are studied, found to be considerably larger than aromatic ? in benzene. A name saturnenes suggested these atom-inside-ring ...

The microwave spectrum of y-thiobutyrolactone has been observed and measured in the vibrational ground state and in several excited states of the ring-bending and ring-twisting modes. From the value of the /ic component of the dipole moment and inertial-defect considerations the ring skeleton was shown to be non-planar. The average intensity ratio for the rotational transitions between the grou...

REVIOUS papers from this laboratory have dealt with segregation of antiP genic characters of the red blood cells, peculiar to one or the other of the parental species, in hybrids from matings between Pearlneck (S t rep tope lk chinensis) and Ring dove (St. risoria) , Pearlneck and Senegal (St. senegalensis), and others. The use of the immunological technics described in these papers gave result...

The mol-ecule of the title compound, C(26)H(34)O(8), a prednisolone derivative, contains three six-membered rings (A, B and C) and one five-membered ring (D). Ring A is planar and rings B and C adopt chair conformations, while ring D adopts an envelope conformation with the C atom bonded to the methyl group at the flap. The crystal structure is stabilized by intermolecular O-H⋯O hydrogen bonds.

The title compound, C(21)H(32)O(3), results from modifications of the A and D rings of the aromatase substrate androstenedione. Ring A adopts a conformation between 10β-sofa and 1α,10β half-chair. Rings B and C are in slightly flattened chair conformations. Ring D approaches a 13β-envelope conformation, probably due to the acet-oxy substituent, and shows a very short Csp(3)-Csp(3) bond next to ...

The stereoselective synthesis of D-fagomine, D-3-epi-fagomine, and D-3-epi-fagomine analogs starting from readily available D-glyceraldehyde acetonide has been achieved. The synthesis involves diastereoselective anti-vinylation of its homoallylimine, ring-closing metathesis, and stereoselective epoxidation followed by regioselective ring-opening or stereoselective dihydroxylation. The lack of a...

The main purpose of this paper is to prove the following result. Let X be a real or complex Banach space, let L(X) be the algebra of all bounded linear operators on X, let A(X) ⊆ L(X) be a standard operator algebra, and let T : A(X) → L(X) be an additive mapping satisfying the relation T (A2n+1) = 2n+1 ∑ i=1 (−1)i+1Ai−1T (A)A2n+1−i, for all A ∈ A(X) and some fixed integer n ≥ 1. In this case T ...

The Boolean ring $B$ of measurable subsets of the unit interval, modulo sets of measure zero, has proper radical ideals (for example, ${0})$ that are closed under the natural metric, but has no prime ideal closed under that metric; hence closed radical ideals are not, in general, intersections of closed prime ideals. Moreover, $B$ is known to be complete in its metric. Togethe...

Let G be a nite subgroup of GL d (Z). Then G acts on the Laurent polynomial ring kX 1 1 d ] over the eld k via the natural G-action on the multiplicative group generated by the variables X 1 ; : : : ; X d (= Z d). We show that the class group of the ring of invariants of this action is isomorphic to Hom(G=N;k) H 1 (G=D; (Z d) D), where N denotes the subgroup of G that is generated by all reeect...

Highly accurate and precise crystal structures of methyl R-D-arabinofuranoside, methyl â-D-ribofuranoside, methyl R-D-lyxofuranoside, and methyl R-D-xylofuranoside have been determined at 100 K by X-ray crystallography. The structures of methyl R-D-arabinofuranoside and methyl â-D-ribofuranoside have also been determined at 15 K by neutron diffraction. Equilibrium (re) geometries of the same co...