Selective Bromochlorination of endo-1,4-Dibromotricyclo[5.2.1.02,6]deca-3,8-diene-5,10-dione 10-Ethylene Acetal at the Conjugated Carbon-Carbon Double Bond

1994 ◽  
Vol 47 (5) ◽  
pp. 963 ◽  
Author(s):  
RW Gable ◽  
KJ Parker ◽  
J Tsanaktsidis
Keyword(s):  
Double Bond ◽  
Thionyl Chloride ◽  
X Ray ◽  
Bromine Chloride ◽  
X Ray Crystallography ◽  
Carbon Double Bond ◽  
Selective Addition ◽  
Ethylene Acetal

Exposure of (1) to bromine in thionyl chloride/ dimethylformamide produced (5), the result of regio- and stereo-selective addition of bromine chloride across the carbonyl-conjugated double bond. The structure of (5) was determined by X-ray crystallography, and its mode of formation is discussed in terms of the carbonyl attack mechanism.

Heterometallische Cluster durch ligandunterstützte Metallfragmentkondensation / Heterometallic Clusters by Ligand Assisted Metal Fragment Condensation

1991 ◽  
Vol 46 (9) ◽  
pp. 1169-1176 ◽  
Author(s):  
Wolfgang Rohde ◽  
Gert Fendesak
Keyword(s):  
Double Bond ◽  
Chelate Complexes ◽  
Heterometallic Clusters ◽  
X Ray ◽  
X Ray Crystallography ◽  
Inert Solvent ◽  
Fragment Condensation ◽  
Olefinic Double Bond ◽  
High Yields ◽  
Iron Fragment

Dicobalt complexes of 3-vinylpropargylic alcohol derivatives react with biscyclooctenetricarbonyliron to give new chelate complexes of the iron tricarbonyl fragment with the olefinic double bond and the alcohol oxygen atom bound to the iron fragment. These compounds react upon heating in an inert solvent to give FeCo-alkynyl cluster complexes in high yields. One of these compounds has been structurally characterized by X-ray crystallography.

ChemInform Abstract: X-Ray Crystal and ab initio Structure of 3-Ethynylcyclopropene: A Curiously Short Carbon-Carbon Double Bond.

ChemInform ◽  
2010 ◽  
Vol 29 (38) ◽  
pp. no-no
Author(s):  
K. K. BALDRIDGE ◽  
B. BIGGS ◽  
D. BLAESER ◽  
R. BOESE ◽  
R. D. GILBERTSON ◽  
...  
Keyword(s):  
Double Bond ◽  
Ab Initio ◽  
X Ray ◽  
Carbon Double Bond ◽  
Ab Initio Structure ◽  
Short Carbon

Secondary compounds in the catalytic hydrogenation of enone and allylic alcohol prostaglandin intermediates: isolation, characterization, and X-ray crystallography

2019 ◽  
Vol 43 (20) ◽  
pp. 7582-7599
Author(s):  
Constantin I. Tănase ◽  
Florea Cocu ◽  
Constantin Drăghici ◽  
Anamaria Hanganu ◽  
Lucia Pintilie ◽  
...  
Keyword(s):  
Double Bond ◽  
Catalytic Hydrogenation ◽  
Secondary Compounds ◽  
Allylic Alcohol ◽  
Side Chain ◽  
X Ray ◽  
X Ray Crystallography

Hydrogenation of the double bond in the ω-side chain of prostaglandin intermediates: conditions to increase the yield and minimize the formation of secondary compounds.

A compound with a tin-carbon double bond, bis(2,4,6-triisopropylphenyl)(fluorenylidene)stannane: aspects of its reactivity and X-ray structure of its dimer

1993 ◽  
Vol 458 (1-2) ◽  
pp. 49-56 ◽  
Author(s):  
G. Anselme ◽  
J.-P. Declercq ◽  
A. Dubourg ◽  
H. Ranaivonjatovo ◽  
J. Escudié ◽  
...  
Keyword(s):  
Double Bond ◽  
X Ray ◽  
Carbon Double Bond

scholarly journals Polymerization of Propene with Modified Constrained Geometry Complexes. Double-Bond Isomerization in Pendant Alkenyl Groups Attached to Cyclopentadienyl Ligands

2003 ◽  
Vol 68 (6) ◽  
pp. 1119-1130 ◽  
Author(s):  
Oetze K. B. Staal ◽  
Dirk J. Beetstra ◽  
Andries P. Jekel ◽  
Bart Hessen ◽  
Jan H. Teuben ◽  
...  
Keyword(s):  
Double Bond ◽  
Spectroscopic Data ◽  
Catalyst Activity ◽  
X Ray ◽  
X Ray Crystallography ◽  
Molecular Weights ◽  
Constrained Geometry ◽  
Internal Position ◽  
Moderate Effect ◽  
C Nmr

Polymerization of propene with dimethylsilylene-bridged (amidocyclopentadienyl)dichlorotitanium(IV) complexes [TiCl2{η5-1-(t-BuSiMe2N-κN)-2,3,4-Me3-5-R-C5}], where R = Me (1), H (2), Ph (3), 4-fluorophenyl (4), but-2-en-2-yl (5), and butyl (6), combined with excess methylaluminoxane revealed a moderate effect of the substituent R on the catalyst activity and the molecular weight of polypropene. The asymmetric substitution in the position adjacent to the bridging carbon atom resulted in polymer yields decreasing in the order 1 > 6 > 3 ≈ 5 > 4 > 2 while polymers with the molecular weights (Mw) close to 2.5 × 105 for 1, 3, and 4, 1.5 × 105 for 5 and 6, and 7.5 × 104 for 2 were obtained. The 13C NMR analysis of the polymers has shown that atactic polypropene is slightly enriched with syndiotactic triads for all the catalysts. Investigation of the crystal structure of 5 by X-ray crystallography revealed that the double bond in but-3-en-2-yl had shifted to an internal position to give the isomeric, but-2-en-2-yl-substituted complex. Likewise, the spectroscopic data for complex 7 prepared from the ligand containing but-3-en-1-yl substituent, indicate the absence of terminal double bond.

A Convenient Synthesis of Tetrasubstituted Pyrazoles from Nitrile Imines and 2-(Thioxothiazolidin-5-ylidene)acetates

Synlett ◽  
2018 ◽  
Vol 29 (07) ◽  
pp. 918-921 ◽  
Author(s):  
Issa Yavari ◽  
Zohreh Taheri ◽  
Maryam Naeimabadi ◽  
Samira Bahemmat ◽  
Mohammad Halvagar
Keyword(s):  
Double Bond ◽  
Dipolar Cycloaddition ◽  
Pyrazole Derivatives ◽  
X Ray ◽  
X Ray Crystallography ◽  
Hydrazonoyl Chlorides ◽  
Convenient Synthesis ◽  
Nitrile Imines ◽  
Fast Access

Alkyl 2-(3-alkyl-4-oxo-2-thioxothiazolidin-5-ylidene)acetates react with hydrazonoyl chlorides in the presence of triethylamine to ­afford tetrasubstituted pyrazole derivatives. Formally, this transformation is regarded as a 1,3-dipolar cycloaddition of the exocyclic carbon–carbon double bond of the thioxothiazolidine derivatives with nitrile imines generated in situ. This efficient method provides fast access to a range of structurally diverse pyrazoles. The structure of a typical product is confirmed by X-ray crystallography.

A Concise Synthesis of 24,25-Dihydro-6-epi-Monanchosterol A

Synlett ◽  
2021 ◽  
Author(s):  
Hans-Günther Schmalz ◽  
Ömer Taspinar ◽  
Vladimir Kjartan Stojadinovic ◽  
Jörg-Martin Neudörfl
Keyword(s):  
Double Bond ◽  
Title Compound ◽  
Protecting Group ◽  
Structural Analogue ◽  
X Ray ◽  
X Ray Crystallography ◽  
Anti Inflammatory ◽  
Aldol Addition ◽  
Optimized Conditions

AbstractWe report the first synthetic entry to a steroid with an unusual bicyclo[4.3.1]dec-3-en-10-one A/B ring substructure as a close structural analogue of the anti-inflammatory monanchosterols. Under optimized conditions, regioselective cis-dihydroxylation of the Δ5-double bond of 7-dehydrocholesterol and subsequent Criegee oxidation yields the corresponding 5,6-seco-steroid as a pure Z-isomer which upon treatment with K2CO3 in MeOH diastereoselectively affords 24,25-dihydro-6-epi-monanchosterol A through intramolecular aldol addition (cyclization). The developed three-step sequence proceeds in 17% overall yield without the need of any protecting group. The title compound was characterized by X-ray crystallography.

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