The synthesis and reactivity of α-oxosulfines

1989 ◽  
Vol 67 (3) ◽  
pp. 369-381 ◽  
Author(s):  
Ian W. J. Still ◽  
Donald V. Frazer ◽  
Donna K. T. Hutchinson ◽  
Jeffery F. Sawyer
Keyword(s):  
Crystal Structures ◽  
Reaction Pathway ◽  
Reactive Intermediates ◽  
Crystallographic Analysis ◽  
Diels Alder ◽  
Electrophilic Addition ◽  
X Ray ◽  
Major Reaction ◽  
Sulfenic Acids

Thiochroman-4-one and cyclohexanone have been converted into the corresponding α-oxosulfines and the behaviour of these reactive intermediates with a range of alkenes and alkynes has been examined. In contrast to some earlier work, the major reaction pathway does not involve formation of the initially expected Diels–Alder adducts but instead a series of adducts involving electrophilic addition to the alkene or alkyne, with concomitant deoxygenation and incorporation of chlorine. The structures of these adducts have been determined by the usual spectroscopic means and, in two representative cases, by X-ray crystallographic analysis. The crystal structures, which include unusual features such as relatively short S … O nonbonding contacts, are discussed in detail. Keywords: (α-oxo)sulfines, sulfenic acids, X-ray analysis, electrophilic addition.

The Chemistry of the Zinc Oxide Cure of Halobutyl

1984 ◽  
Vol 57 (4) ◽  
pp. 813-825 ◽  
Author(s):  
I. Kuntz ◽  
R. L. Zapp ◽  
R. J. Pancirov
Keyword(s):  
Zinc Oxide ◽  
Zinc Chloride ◽  
Reaction Pathway ◽  
Diels Alder ◽  
Crosslinking Reaction ◽  
Conjugated Diene ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds ◽  
Chloride Catalyst ◽  
Major Reaction

Abstract The studies described in this papier lead to certain conclusions. The crosslinking reaction of halobutyl with zinc oxide does not give rise to ether crosslinks. All the evidence indicates that the chemistry involves the formation of carbon-carbon bonds by an alkylation type chemistry. The dehydrohalogenation of the halobutyl to form a zinc chloride catalyst is a key feature of the crosslinking chemistry. But conjugated diene butyl and Diels-Alder reactions are not the major reaction pathway for the zinc oxide crosslinking reaction. These conclusions have significance for the zinc oxide cure of CR which has an active allylic halide structure formed by 1,2-monomer enchainment.

Imidazole/benzimidazole-modified cyclotriphosphazenes as highly selective fluorescent probes for Cu2+: synthesis, configurational isomers, and crystal structures

2017 ◽  
Vol 46 (28) ◽  
pp. 9140-9156 ◽  
Author(s):  
Aylin Uslu ◽  
Süreyya Oğuz Tümay ◽  
Ahmet Şenocak ◽  
Fatma Yuksel ◽  
Elif Özcan ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Fluorescent Probes ◽  
Copper Ion ◽  
Crystallographic Analysis ◽  
Ion Detection ◽  
X Ray

We present a comprehensive work and discuss the fluoroprobe properties of synthesized compounds for copper ion detection with a stereochemical approach using X-ray crystallographic analysis results.

Silaheterocyclen, XX Aminosubstituierte Vinylchlorsilane und Silaethene: Bausteine zur Synthese von 1,3-Diaza-2-silacyclopentanen / Silaheterocycles, XX Aminosubstituted Vinylchlorosilanes and Silenes: Building Blocks for the Synthesis of 1,3-Diaza-2-silacyclopentanes

1992 ◽  
Vol 47 (10) ◽  
pp. 1377-1385 ◽  
Author(s):  
Norbert Auner ◽  
Erika Penzenstadler ◽  
Eberhardt Herdtweck
Keyword(s):  
Reaction Pathway ◽  
Addition Product ◽  
Building Blocks ◽  
Diels Alder ◽  
Main Reaction ◽  
Intramolecular Rearrangement ◽  
X Ray Diffraction ◽  
Great Tendency ◽  
X Ray ◽  
Frame Work

The amino-substituted vinylchlorosilanes 4-7 are synthesized from N,N,N′-trimethylethylenediamine (8a) or tris(trimethylsilyl)ethylenediamine (8b), Li Bun and organodichlorovinylsilanes. 5 eliminates trimethylchlorosilane when distilled and yields 1,3-diaza-2-silacyclopentane 9, whereas the compounds 6 and 7 show a great tendency to oligomerize. The reaction of 4 with LiBut gives a neopentylsilene intermediate 10 a which can be trapped by isoprene or 1,3-butadiene yielding small amounts of the Diels-Alder products 11 and 12, respectively. The main reaction pathway for 10 a is rearrangement with migration of a Me3Sigroup from nitrogen to the silene’s carbon atom and a new N—Si bond formation to give the diazasilacyclopentane 10 which has been characterized by X-ray diffraction analysis. This intramolecular rearrangement appears to involve a pentacoordinated silene Si-atom. No dimerisation of 10a to a disilacyclobutane is observed. The introduction of a second Si-tris(trimethylsilyl)ethylenediamine substituent at the SiC frame work does not result in silene stabilisation: there is no evidence for Si-hexacoordination in silene 15 nor in the [4+2] cyclo-addition product with isoprene (14).

Intramolecular Hydrolysis of Coordinated Acetonitrile in a Binuclear Complex of Cobalt(III): X-Ray Crystallographic Analysis of Salts of [(tren)Co(μ-NH2,μ-L)Co(tren)]4+(L=OH, CH3C(O)NH)

1990 ◽  
Vol 43 (4) ◽  
pp. 643 ◽  
Author(s):  
NW Alcock ◽  
II Creaser ◽  
NJ Curtis ◽  
L Roecker ◽  
AM Sargeson ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Binuclear Complex ◽  
Binding Mode ◽  
Crystallographic Analysis ◽  
Bridging Ligands ◽  
X Ray ◽  
Hydrolysis Of

A synthesis of [( tren )Co(μ-NH2,μ-OH)Co( tren )]4+(3)( tren = tris (2- aminoethyl )amine) is reported along with a series of derivatives: [( tren ) XCo (μ-NH2) CoX ( tren )]n+, where X = CF3SO3- (n = 3)(4), X = CH3CN (n = 5)(5), and [( tren )Co(μ-NH2,μ-CH3C(O)NH)Co( tren )]4+ (6). The substitution of (4) by CH3CN to yield (5) was studied in CH3CN at 20°C, k = 9.0×10-3 s-1, and the intramolecular hydrolysis of (5) to yield the bridging acetamide complex (6) was studied at various acid concentrations. The X-ray crystal structures were determined for (3b) (exafluorophosphate, dihydrate) and (6b) (dithionate, tetrahydrate ). Both crystals are monoclinic, respectively P21/n with a 11.082(2), b 10.402(2), c 15.611(2)Ǻ, β 99.13(2)°, Z 2, and C2/c with a 14.328(2), b 14.046(1), c 16.497(2)Ǻ, β 101.90(1)°, Z 4. For the salt of (3), 2389 data with 1 ≥ 2σ(I) were refined to R 0.070 ( Rw 0.066), and, for the salt of (6), 3087 data with I ≥ 3σ(I) were refined to R 0.041 ( Rw 0.056). Both ions lie on pseudo-symmetric sites involving disorder of the bridging ligands . The structures establish the binding mode of the acetamido ion and the orientation of the tren groups in the isolated complexes.

Chemistry and crystal structures of tetrabenzoylethylene, its photolysis product and tetraacetylethylene

1978 ◽  
Vol 31 (6) ◽  
pp. 1265 ◽  
Author(s):  
JR Cannon ◽  
VA Patrick ◽  
CL Raston ◽  
AH White
Keyword(s):  
Solid State ◽  
Crystal Structures ◽  
Molecular Conformation ◽  
Crystallographic Analysis ◽  
Stable Form ◽  
Photolysis Product ◽  
Molecular Conformations ◽  
X Ray ◽  
The Difference ◽  
The Stability

X-ray crystallographic analysis has revealed that the light-sensitive form (A) and the light-stable form (A') of tetrabenzoylethylene are not valence tautomers but are two crystalline modifications of the same substance. The difference in the stability of these forms to light appears to be a consequence of their different molecular conformations and packing in the solid state. The molecular conformation of the A form is represented by (8) and that of the A' form by (9). The related tetraacetylethylene has the conformation (10) in the solid state. X-ray crystallographic analysis has also revealed that the photolysis product (B) of tetrabenzoylethylene is 4-phenoxy-3,4,6-triphenyl-1H,4H-furo[3,4-c]-furan-1-one (11). ��� The crystal structures of (8), (9), (10) and (11) were determined by X-ray diffraction: diffractometer data at 295 K were refined by least-squares techniques to residuals of 0.064 (2161 'observed' reflections) for (8), 0.057 (1310) for (9), 0.049 (1295) for (10) and 0.061 (1639) for (11). Crystals of (8) are monoclinic, P21/n, a 8.775(5), b 17.352(9), c 30.985(8)Ǻ, β 93.01(3)°, Z 8. Crystals of (9) which contain carbon disulfide are monoclinic, A2/a, a 21.21(2), b 6.181(4), c 20.35(2) Ǻ, β 102.77(7)°, Z 4. Crystals of (10) are monoclinic, P21/n, a 7.540(2), b 4.392(2), c 14.770(4) Ǻ, β 96.29(2)°, Z 2. Crystals of (11) are monoclinic, P1/n, a 14.820(4), b 15.000(3), c 10.819(4)Ǻ, β 106.02(2)°, Z 4.

X-ray Structural Analysis for the Prediction on the Nature of the Retro Diels - Alder Pathway: Concerted or Stepwise. Structural Studies on Nitrosobenzene Cycloadducts

2009 ◽  
Vol 62 (12) ◽  
pp. 1695 ◽  
Author(s):  
Jesse Roth-Barton ◽  
Jonathan M. White
Keyword(s):  
Structural Analysis ◽  
Crystal Structures ◽  
Diels Alder ◽  
Structure Parameters ◽  
Structural Studies ◽  
Structural Effects ◽  
X Ray ◽  
Early Stages ◽  
Clear Differentiation

Crystal structures of nitrosobenzene cycloadducts 5–7 reveal structural effects consistent with the early stages of the retro Diels–Alder fragmentation. There is a clear differentiation between the structure parameters of cycloadduct 5, which reacts by a concerted synchronous pathway and that of cycloadduct 6, which must react by a two-step pathway. Based on these data, cycloadduct 7 is predicted to react by a highly asynchronous or two-step pathway.

Stereoselective synthesis and X-ray crystallographic analysis of mixed 6,6-dihalo penicillanates

1985 ◽  
Vol 63 (11) ◽  
pp. 3177-3181 ◽  
Author(s):  
Diego U. Belinzoni ◽  
Oreste A. Mascaretti ◽  
Pedro M. Alzari ◽  
Graciela Punte ◽  
Carlos Faerman ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Stereoselective Synthesis ◽  
Crystallographic Analysis ◽  
Displacement Reaction ◽  
X Ray ◽  
Single Crystal Analysis

The pivaloyloxy methyl 6,6-dihalo penicillanates 1a, 1b, and 1c have been stereoselectively prepared from the reaction of pivaloyloxy methyl 6-diazo penicillanate 2 with either N-halosuccinimide/halide or the interhalogens Xl (X = Cl, Br). The crystal structures of 3S,5R,6R pivaloyloxy methyl 6-bromo, 6-chloro penicillanate1a; 3S,5R,6R pivaloyloxy methyl 6-iodo, 6-bromo penicillanate 1b, and 3S, 5R, 6R pivaloyloxymethyl 6-iodo, 6-chloro penicillanate 1c have been determined by X-ray single crystal analysis. The stereochemistry of the displacement reaction is discussed.

3,10-Dihydroxydielmentha-5,11-Diene-4,9-Dione. A Diterpenoid (Bismonoterpenoid) With a Novel Carbon Skeleton

1986 ◽  
Vol 39 (11) ◽  
pp. 1843 ◽  
Author(s):  
RM Carman ◽  
LK Lambert ◽  
WT Robinson ◽  
n Vandonge
Keyword(s):  
High Field ◽  
Crystallographic Analysis ◽  
Diels Alder ◽  
Carbon Skeleton ◽  
Two Dimensional ◽  
X Ray

3,10-Dihydroxydielmentha-5,11-diene-4,9-dione, a diterpenoid (C20H28O4) from Callitris macleayana heartwood, is shown by degradation, by both one- and two-dimensional high-field n.m.r. exploration, and by X-ray crystallographic analysis to have a unique carbon skeleton formally based upon the Diels-Alder self- dimerization of a p- menthadienone.

X-Ray Crystallographic Analysis of 2,5-Bis(diphenylmethylsilyl)thiophene Monooxide and the Diels-Alder Reaction of Thiophene Monooxide with Dienophiles

Heterocycles ◽  
1998 ◽  
Vol 47 (2) ◽  
pp. 793 ◽  
Author(s):  
Naomichi Furukawa ◽  
Shao-Zhong Zhang ◽  
Ernst Horn ◽  
Ohgi Takahashi ◽  
Soichi Sato ◽  
...  
Keyword(s):  
Alder Reaction ◽  
Crystallographic Analysis ◽  
Diels Alder ◽  
X Ray ◽  
Diels Alder Reaction

Diels–Alder reactions of 3,6-disubstituted 1,2,4,5-tetrazines. Synthesis and X-ray crystal structures of diazafluoranthene derivatives

2009 ◽  
Vol 7 (10) ◽  
pp. 2082 ◽  
Author(s):  
Nelli Rahanyan ◽  
Anthony Linden ◽  
Kim K. Baldridge ◽  
Jay S. Siegel
Keyword(s):  
Crystal Structures ◽  
Diels Alder ◽  
X Ray
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