The Question of Conformational Restriction in the trans-Cyclononene Ring of Caryophyllene

1973 ◽  
Vol 51 (23) ◽  
pp. 3955-3962 ◽  
Author(s):  
E. W. Warnhoff ◽  
V. Srinivasan
Keyword(s):  
Double Bond ◽  
Room Temperature ◽  
Membered Ring ◽  
Trans Double Bond ◽  
Conformational Restriction

The possibility that the barrier to rotation of the trans double bond within the nine-membered ring of caryophyllene might be high enough to prevent the interconversion of conformers 2 and 3 near room temperature has been examined. Contrary to earlier reports, it has been found that two trans epoxides are formed on peracid epoxidation of caryophyllene and hence both conformers are present. Attempts to determine whether 2 and 3 are interconverting near room temperature were inconclusive.

One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water

2018 ◽  
Vol 15 (3) ◽  
pp. 380-387
Author(s):  
Xia Zhao ◽  
Xiaoyu Lu ◽  
Lipeng Zhang ◽  
Tianjiao Li ◽  
Kui Lu
Keyword(s):  
Double Bond ◽  
Efficient Method ◽  
Room Temperature ◽  
Sulfonyl Chloride ◽  
Antibacterial Activities ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Amide Form

Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

scholarly journals Silylated gallium and indium chalcogenide ring systems as potential precursors to ME (E=O, S) materials

2013 ◽  
Vol 11 (7) ◽  
pp. 1225-1238
Author(s):  
Iliana Medina-Ramírez ◽  
Cynthia Floyd ◽  
Joel Mague ◽  
Mark Fink
Keyword(s):  
Thermal Decomposition ◽  
Room Temperature ◽  
Membered Ring ◽  
Molecular Structures ◽  
Nmr Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
High Yields ◽  
Vt Nmr ◽  
State 1

AbstractThe reaction of R3M (M=Ga, In) with HESiR′3 (E=O, S; R′3=Ph3, iPr3, Et3, tBuMe2) leads to the formation of (Me2GaOSiPh3)2(1); (Me2GaOSitBuMe2)2(2); (Me2GaOSiEt3)2(3); (Me2InOSiPh3)2(4); (Me2InOSitBuMe2)2(5); (Me2InOSiEt3)2(6); (Me2GaSSiPh3)2(7); (Et2GaSSiPh3)2(8); (Me2GaSSiiPr3)2(9); (Et2GaSSiiPr3)2(10); (Me2InSSiPh3)3(11); (Me2InSSiiPr3)n(12), in high yields at room temperature. The compounds have been characterized by multinuclear NMR and in most cases by X-ray crystallography. The molecular structures of (1), (4), (7) and (8) have been determined. Compounds (3), (6) and (10) are liquids at room temperature. In the solid state, (1), (4), (7) and (9) are dimers with central core of the dimer being composed of a M2E2 four-membered ring. VT-NMR studies of (7) show facile redistribution between four- and six-membered rings in solution. The thermal decomposition of (1)–(12) was examined by TGA and range from 200 to 350°C. Bulk pyrolysis of (1) and (2) led to the formation of Ga2O3; (4) and (5) In metal; (7)–(10) GaS and (11)–(12) InS powders, respectively.

Additionen an die Si=N-Doppelbindung – Kristallstruktur eines (SiNCO)-Vierringes / Additions to the Si=N-Double Bond - Crystal Structure of a (SiNCO)-Four Membered Ring

1991 ◽  
Vol 46 (6) ◽  
pp. 709-713 ◽  
Author(s):  
Susanne Vollbrecht ◽  
Uwe Klingebiel ◽  
Dieter Schmidt-Bäse
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Single Crystals ◽  
Membered Ring ◽  
Thermal Cleavage

In the reaction with benzophenone and phenylaldehyde lithiated aminofluorosilanes behave like iminosilanes. Four membered rings are formed in (2+2) cycloadditions. The oxaazasilacyclobutane ((CMe3)2Si—NCMe3—C6H5CH—O—) was purified by destillation. Single crystals were obtained by recrystallization from hexane. The thermal cleavage of the (SiNCO)-rings leads to carboimines and cyclosiloxanes. The lithium derivate of di-tert-butylfluorosilyl-2.6-diisopropylphenylamine reacts with 2-methyl-propenal-2 in two competing ways. In a (2+4) cycloaddition an 1-oxa-3-aza-2-sila-5-cyclohexene is formed, and in a (2+2) cycloaddition 2-methyl-2-propenyl-N-(2.6-diisopropylphenyl)imine is generated via an (SiNCO)-ring intermediate.

scholarly journals Photochemische Reaktionen von Übergangsmetall-Olefin-Komplexen, V [1]. Die Umsetzung von Tricarbonyl-η-6.6-dimethylfulven-chrom(0) mit 7-Methyl- und 7-Methoxycycloheptatrien / Photochemical Reactions of Transition Metal Olefin Complexes, V [1]. The Reactions of Tricarbonyl-η-6,6-dimethylfulvene-chromium(0) with 7-Methyl- and 7-Methoxycycloheptatriene

1982 ◽  
Vol 37 (10) ◽  
pp. 1322-1326 ◽  
Author(s):  
Cornelius G. Kreiter ◽  
Hans Kurz
Keyword(s):  
Nmr Spectroscopy ◽  
Transition Metal ◽  
Column Chromatography ◽  
Room Temperature ◽  
Photochemical Reactions ◽  
Membered Ring ◽  
Reaction Products ◽  
Methyl Group

Abstract The stereochemistry of the photo reaction products of tricarbonyl-η-6,6-dimethyl-fulvene-chromium(O) (1) with 7-methyl-and 7-methoxycycloheptatriene was studied by NMR-spectroscopy. Both trienes add to 1, displace a CO ligand, and form substituted dicarbonyl-η3-2-cycloheptadienylene-η5-2-cyclopentadienylidene-propane-chromium(0) complexes. With C7H7CH3 only one isomer (3) is formed with the methyl-group in endo-position and the enyl system encompassing C(1′)-C(3′) of the seven membered ring. C7H7OCH3 yields 3 isomers which were separated by column chromatography. 5 has the same constitution as 3. The isomers 4 and 5 bear the OCH3-group in e^o-position. The enyl system of 4 is located on C(1′)-C(3′), that of 6 on C(3′)-C(5′). 6 rearranges at room temperature to 4.

Das dynamische Verhalten des 1-Methyl-1-benzothiepinium-Ringsystems/The Dynamic Behaviour of the 1-Methyl-1-benzothiepinium Ring System

1981 ◽  
Vol 36 (8) ◽  
pp. 974-977 ◽  
Author(s):  
Hans Hofmann ◽  
Franz Dickert
Keyword(s):  
Nmr Spectroscopy ◽  
Room Temperature ◽  
Dynamic Behaviour ◽  
Ring System ◽  
Membered Ring ◽  
Ring Inversion ◽  
Methyl Group ◽  
H Nmr ◽  
Pyramidal Inversion ◽  
Mutual Conversion

Abstract By 1H NMR spectroscopy the stereochemistry of the 1-methyl-1-benzothiepinium ring system was investigated both in thermodynamic and kinetic respects. It was shown that in solution a rapid mutual conversion of the boat shaped seven membered ring system with exo-respectively endo-S-methyl group occurs via a ring inversion and not by a pyramidal inversion at the sulfonium ion. At room temperature predominantly the conformation with the exo-S-methyl group is present.

scholarly journals Oxidation of geraniol using niobia modified with hydrogen peroxide

2019 ◽  
Author(s):  
Jairo Cubillos ◽  
José J. Martínez ◽  
Hugo Rojas ◽  
Norman Marín-Astorga
Keyword(s):  
Hydrogen Peroxide ◽  
Transition State ◽  
Kinetic Data ◽  
Room Temperature ◽  
Membered Ring ◽  
Morphological Properties ◽  
Peroxo Complex ◽  
Complex Species ◽  
Ring Transition State

Nb2O5 bulk and Nb2O5 modified with H2O2 were studied in the epoxidation of geraniol at 1 bar and room temperature. The structural and morphological properties for both catalysts were very similar, indicating that the peroxo-complex species were not formed. The order of the reaction was one respect to geraniol and close to zero respect to H2O2, these values fit well with the kinetic data obtained. The geraniol epoxidation is favored by the presence of peroxo groups, which is reached using an excess of H2O2. Moreover, the availability of the geraniol to adopt the three-membered-ring transition state was found as the best form for this type of compound.

Heats of vaporization and gaseous heats of formation of some five- and six-membered ring alkenes

1979 ◽  
Vol 57 (17) ◽  
pp. 2302-2304 ◽  
Author(s):  
Richard Fuchs ◽  
L. Alan Peacock
Keyword(s):  
Gas Chromatography ◽  
Double Bond ◽  
Heat Capacities ◽  
Membered Ring ◽  
Heats Of Formation ◽  
Group Additivity ◽  
Liquid Heat ◽  
Heats Of Vaporization

The heats of vaporization of 1-methylcyclopentene, 3-methylcyclopentene, ethylidenecyclopentane, 1-ethylcyclopentene, methylenecyclohexane, allylcyclopentane, vinylcyclohexane, ethylidenecyclohexane, allylcyclohexane, 3,3-diethylpentane, 2,2,4,4-tetramethylpentane, and trans-2,2,5,5-tetramethyl-3-hexene have been measured by the gas chromatography – calorimetry method. These values have been combined with previously reported liquid heats of formation to give gaseous values of ΔHf. The results indicate that the internal double bond is favored by about 0.5 kcal over the exo in both 5- and 6-membered rings, but the endo–exo differences are much smaller than previously believed. Several of the liquid heat capacities that were measured were not well predicted by group additivity schemes.

scholarly journals 1-Phenyl-3H-2,3-benzodiazepin-4(5H)-one

2012 ◽  
Vol 68 (8) ◽  
pp. o2443-o2443
Author(s):  
Ballo Daouda ◽  
Frédéric Bihel ◽  
Mouhamadou Lamine Doumbia ◽  
El Mokhtar Essassi ◽  
Seik Weng Ng
Keyword(s):  
Hydrogen Bond ◽  
Double Bond ◽  
Title Compound ◽  
Membered Ring ◽  
Unit Cell ◽  
Orthorhombic Unit Cell ◽  
Compound C

The seven-membered ring in the title compound, C15H12N2O, adopts a boat-shaped conformation (with the methylene C atom as the prow and the double-bond C=N pair of atoms as the stern). In the crystal, adjacent molecules are linked by an N—H...O hydrogen bond to generate helical chains running along theaaxis of the orthorhombic unit cell.

The methylgallium-2-carboxylatobenzimidazolato hexamer, [MeGa·C8H4N2O2]6·C6H6·(Me2C6H4)2; synthesis and X-ray crystal structure

1999 ◽  
Vol 77 (4) ◽  
pp. 434-438 ◽  
Author(s):  
Steven J Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Room Temperature ◽  
Direct Methods ◽  
Membered Ring ◽  
Coordination Geometry ◽  
Temperature Reaction ◽  
Full Matrix ◽  
X Ray ◽  
Solvent Molecules

The room-temperature reaction of Me3Ga with benzimidazole 2-carboxylic acid in xylene solvent has yielded a novel crystalline hexameric gallium compound with "MeGa" moieties bridged by the doubly depronotated ligand precursor. Crystals of [MeGa(4,5-benzimidazolato-2-carboxylato)]6·(C6H6)·(m-Me2C6H4)2 are monoclinic, a = 18.091(2), b = 17.094(2), c = 13.2215(5) Å, Z = 2, space group C2/m. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R (F, I [Formula: see text] 3σ(I)) = 0.064 (Rw (F2, all data) = 0.134). The hexameric Ga complex contains a six-membered ring of Ga atoms, bridged by the benzimidazolate ligands with the benzo rings projecting alternately above and below the Ga plane, thus forming a ball-shaped molecule. The complex could have ideal D3d symmetry, but it contains an encapsulated molecule of benzene, which distorts the regularity of the Ga6 hexagon, and reduces the symmetry of the complex to the crystallographically observed C2h. The coordination geometry at each of the two independent GaO2N2C centres approximates a trigonal bipyramid, with a N2C trigonal plane, and the O atoms above and below; average dimensions are Ga-O = 2.176(2), Ga-N = 1.973(3), Ga-C = 1.927(5) Å, O-Ga-O = 165°. The unit cell also contains four m-xylene solvent molecules (outside the molecular cage).Key words: gallium, crystal structure, benzene intercalate, benzimidazolecarboxylic acid.

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