Synthesis and X-Ray Crystal Structure of Cynandione B Analogues

2012 ◽  
Vol 65 (1) ◽  
pp. 58 ◽  
Author(s):  
Lisa P. T. Hong ◽  
Jonathan M. White ◽  
Christopher D. Donner
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
Structural Requirements ◽  
Relative Configuration ◽  
X Ray ◽  
One Step ◽  
The One

The synthesis of analogues of cynandione B, a phenolic acetophenone from Cynanchum taiwanianum, is described. The one-step conversion of benzochromenones to the heptacyclic spiroacetal core of cynandione B using methylmagnesium bromide is investigated and structural requirements for this novel transformation established. X-ray crystal structure analysis has established the relative configuration in these unusual heterocycles.

1,3-Dipolar [3+3] Cycloaddition of 1,4-Benzodiazepinone-Based Nitrones with α-Halohydroxamates for Diastereoselective Synthesis of Novel d-Edge Heterocycle-Fused 1,4-Benzodiazepinones

Synlett ◽  
2021 ◽  
Author(s):  
Hong-Wu Zhao ◽  
Heng Zhang ◽  
Lu-Yu Cai ◽  
Zhe Tang ◽  
Xiao-Zu Fan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Reaction Mechanism ◽  
Single Crystal ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
Diastereoselective Synthesis ◽  
Reaction Conditions ◽  
Relative Configuration ◽  
X Ray ◽  
Single Crystal Structure Analysis

Promoted by K2CO3 (2.0 equiv), the 1,3-dipolar [3+3] cycloaddition between 1, 4-benzodiazepinone-based nitrones and α-halohydroxamates processed smoothly under the mild reaction conditions and delivered structurally novel and complex cis or trans-configured d-edge-heterocycle-fused 1,4-benzodiazepinones in up to >99% isolated yield with >20:1 dr. The relative configuration of the title chemical entities was clearly identified with the use of X-ray single crystal structure analysis. The reaction mechanism was assumed to interpret the diastereoselective production of the obtained cis or trans-configured d-edge-heterocycle-fused 1, 4-benzodiazepinones.

Synthesis and One-Electron Oxidation Chemistry of Stable β,β-Dimesityl Enols with Heteroaryl Substituents

2003 ◽  
Vol 58 (9) ◽  
pp. 877-884 ◽  
Author(s):  
Michael Schmittel ◽  
Mukul Lal ◽  
Wolfdieter A. Schenk ◽  
Michael Hagel ◽  
Nicolai Burzlaff ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Intramolecular Cyclization ◽  
Crystal Structure Analysis ◽  
X Ray ◽  
Oxidation Potentials ◽  
The One ◽  
Oxidation Chemistry

Four novel stable enols (one characterized by X-ray crystal structure analysis) were synthesized and investigated under oxidative conditions to yield benzofurans. Depending on the donor qualities of the heteroaryl substituent the reaction following the one-electron oxidation could be stopped on the stage of the cyclohexadienyl cation whose lifetime was measured. Oxidation potentials were determined for the enols, the enolates and the α-carbonyl radicals. Oxidation of benzofurans yielded dimeric species or intramolecular cyclization products.

Synthesis of morphan derivatives with additional substituents in 8-position

2016 ◽  
Vol 71 (10) ◽  
pp. 1057-1069
Author(s):  
Janine Stefaowitz ◽  
Dirk Schepmann ◽  
Constantin Daniliuc ◽  
Susumu Saito ◽  
Bernhard Wünsch
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Primary Amine ◽  
Crystal Structure Analysis ◽  
One Pot ◽  
Relative Configuration ◽  
X Ray ◽  
Major Interest ◽  
System 2 ◽  
Sequential Transformation

AbstractThe morphan system (2-azabicyclo[3.3.1]nonane) as a substructure of morphine is of major interest in medicinal chemistry. Herein, the synthesis of morphan derivatives with additional substituents at the propano bridge is reported. In order to avoid the isolation of the smelly and volatile nitrile 6 and the very polar primary amine 9, an efficient one-pot, three-step sequential transformation of the mesylate 5 into amides 10 was developed. The key step of the synthesis was the stereoselective intramolecular opening of the epoxides 11a–d leading to the exo-configured 8-hydroxymorphans 12a–d. The configuration of the exo-configured hydroxymorphan 12d bearing the κ- and σ-pharmacophoric 3,4-dichlorophenylacetyl moiety was inverted by oxidation and stereoselective reduction. An X-ray crystal structure analysis of the benzamide 12c confirmed the relative configuration of the hydroxymorphans 12a–d and 14d.

scholarly journals Preparative-scale HPLC Resolution of Metallacyclic η3-Allyltricarbonyliron Complexes and Determination of the Absolute Configuration by X-Ray Crystal Structure Analysis

1999 ◽  
Vol 23 (9) ◽  
pp. 578-579
Author(s):  
Rainer Schobert ◽  
Hermann Pfab ◽  
Jutta Böhmer ◽  
Frank Hampel ◽  
Andreas Werner
Keyword(s):  
Crystal Structure ◽  
Silica Gel ◽  
Structure Analysis ◽  
Absolute Configuration ◽  
Crystal Structure Analysis ◽  
Preparative Scale ◽  
X Ray ◽  
The Absolute

Racemates of (η3-allyl)tricarbonyliron lactone complex Fe(CO)3{η1:η3-C(O)XCH2CHCMeCH2} 1a (X = O) and (η3-allyl)tricarbonyliron lactam complex 2a (X = NMe) are resolved on a preparative scale by HPLC on cellulose tris(3,5-dimethylphenyl)carbamate/silica gel RP-8 and the absolute configuration of (-)-2a is determined by X-ray crystal structure analysis.

Second-Generation Inhibitors for the Metalloprotease Neprilysin Based on Bicyclic Heteroaromatic Scaffolds: Synthesis, Biological Activity, and X-Ray Crystal-Structure Analysis

2005 ◽  
Vol 88 (4) ◽  
pp. 731-750 ◽  
Author(s):  
Stefan Sahli ◽  
Brian Frank ◽  
W. Bernd Schweizer ◽  
François Diederich ◽  
Denise Blum-Kaelin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Biological Activity ◽  
Structure Analysis ◽  
Second Generation ◽  
Crystal Structure Analysis ◽  
X Ray
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