We study the orbital behavior of Saturn’s satellites Enceladus and Dione during their passage through the 2:1 mean-motion resonances to constrain their interior structures, parameterized by the quantity k2=Q (assumed constant). Enceladus’ evolution after escape from the second-order e-Enceladus e-Dione resonance requires that ðk2=QÞEnceladus < 8 10 , for that QSaturn > 18;000. This result is in...

The repeated introduction of an a-dione unit and its reaction with an arene-1,2-diamine allows the stepwise annulation of all four pyrrolic rings of a porphyrin, as is demonstrated by the synthesis of a trisquinoxalinoporphyrin, a tetrakisquinoxalinoporphyrin and the more elaborated bisporphyrin.

The mol-ecule of buthalital, (I) [systematic name: 5-(2-methyl-prop-yl)-5-(prop-2-en-1-yl)-2-sulfanyl-idene-1,3-diazinane-4,6-dione], C11H16N2O2S, exhibits a planar pyrimidine ring, whereas the pyrimidine ring of methitural, (II) [systematic name: 5-(1-methyl-but-yl)-5-[2-(methyl-sulfan-yl)eth-yl]-2-sulfanyl-idene-1,3-diazinane-4,6-dione], C12H20N2O2S2, is slightly puckered. (I) and (II) contai...

Isothiazolopyridines, pyridothiazines and pyridothiazepines are important compounds that possess valuable biological activities. This paper reports on the synthesis of these compounds using both conventional chemical methods and modern microwave techniques. 3-Bromo-6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-carboxamide, 5-arylazo-6-hydroxy-4-methyl-2-thioxo-1,2-dihydropyridine-3-carboxam...

A set of new bis-spirofused 1,2,4-trioxanes 4a-d was obtained from the reaction of cyclohexane-1,4-dione with allylic hydroperoxides 2a-d, bearing an additional hydroxy group in the homoallylic position, by diastereoselective photooxygenation of allylic alcohols 1a-d and subsequent BF(3)-catalyzed peroxyacetalization with the diketone. From the reaction of a monoprotected cyclohexane-1,4-dione ...

This study includes synthesis and characterization of new derivatives 3-(2-(6-oxo-1,3-thiazinan-3-yl)-R)-1,3-oxazepane-4,7-dione N-Bromo amines 1,3-oxazepane-4,7-dione derivatives. Schiff's bases reactions through one step process in inert solvents. Some employing [1- 4]; addition, synthesized by the reaction different with (Salicylaldehyde) absolute ethanol under reflux. Heterocyclic rings pre...

A concise method for the synthesis of heterocycle-fused naphthoquinones such as naphtho[2,3-b]-furan-4,9-dione, 1H-benz[f]indole-4,9-dione, and naphtho[2,3-b]thiophene-4,9-dione was developed. This method employed Sonogashira coupling and tandem addition-elimination/intramolecular cyclization, and it enabled the preparation of versatile heterocycle-fused naphthoquinones from one substrate.

In the title one-dimensional coordination polymer, [Ag(NO(3))(C(12)H(6)N(2)O(2))](n), the Ag(I) atom is penta-coordinated by two N atoms from a 1,10-phenanthroline-5,6-dione (phen-dione) ligand, one O atom from the nitrate anion and two O atoms from another phen-dione ligand. The coordination environment around silver is slightly distorted square-pyramidal. Inter-estingly, the Ag-O distances to...

Intra and intermolecular interactions found in the developed crystals of synthesized py-ron-2,4-dione derivatives play crucial rules molecular conformations crystal stabili-ties, respectively. In this regard, Hirshfeld calculations were used to quantitatively analyze different structures some functionalized py-ran-2,4-dione derivatives. The X-ray structure pyran-2,4-dione derivative namely (3E,...