Synthesis and structural characterization of an azatitanacyclobutene: the key intermediate in the catalytic anti-Markovnikov addition of primary amines to α-alkynes

2004 ◽  
pp. 704-705 ◽  
Author(s):  
Benjamin D. Ward ◽  
Aline Maisse-François ◽  
Philip Mountford ◽  
Lutz H. Gade
Keyword(s):  
Structural Characterization ◽  
Primary Amines ◽  
Markovnikov Addition

scholarly journals Copper(II) Ketimides in sp3 C-H Amination

2021 ◽  
Author(s):  
Isuri Jayasooriya ◽  
Abolghasem (Gus) Bakhoda ◽  
Rachel Palmer ◽  
Kristi Ng ◽  
Nour Khachemoune ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Primary Amines ◽  
Alkyl Radicals

<p>Commercialy available benzphenone imine (HN=CPh<sub>2</sub>) reacts with b-diketiminato copper(II) <i>tert</i>-butoxide complexes [Cu<sup>II</sup>]-O<i><sup>t</sup></i>Bu to form isolable copper(II) ketimides [Cu<sup>II</sup>]-N=CPh<sub>2</sub>. Structural characterization of the three coordinate copper(II) ketimide [Me<sub>3</sub>NN]Cu-N=CPh<sub>2</sub> reveals a short Cu-N<sub>ketimide</sub> distance (1.700(2) Å) with a nearly linear Cu-N-C linkage (178.9(2)°). Copper(II) ketimides [Cu<sup>II</sup>]-N=CPh<sub>2</sub> readily capture alkyl radicals R• (PhCH(•)Me and Cy•) to form the corresponding R-N=CPh<sub>2</sub> products that competes with N-N coupling of copper(II) ketimides [Cu<sup>II</sup>]-N=CPh<sub>2</sub> to form the azine Ph<sub>2</sub>C=N-N=CPh<sub>2</sub>. Copper(II) ketimides [Cu<sup>II</sup>]-N=CAr<sub>2</sub> serve as intermediates in catalytic sp<sup>3</sup> C-H amination of substrates R-H with ketimines HN=CAr<sub>2</sub> and <i><sup>t</sup></i>BuOO<i><sup>t</sup></i>Bu as oxidant to form <i>N</i>-alkyl ketimines R-N=CAr<sub>2</sub>. This protocol enables the use of unactivated sp<sup>3</sup> C-H bonds to give R-N=CAr<sub>2</sub> products easily converted to primary amines R-NH<sub>2</sub> via simple acidic deprotection.</p>

scholarly journals Copper(II) Ketimides in sp3 C-H Amination

2021 ◽  
Author(s):  
Isuri Jayasooriya ◽  
Abolghasem (Gus) Bakhoda ◽  
Rachel Palmer ◽  
Kristi Ng ◽  
Nour Khachemoune ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Primary Amines ◽  
Alkyl Radicals

<p>Commercialy available benzphenone imine (HN=CPh<sub>2</sub>) reacts with b-diketiminato copper(II) <i>tert</i>-butoxide complexes [Cu<sup>II</sup>]-O<i><sup>t</sup></i>Bu to form isolable copper(II) ketimides [Cu<sup>II</sup>]-N=CPh<sub>2</sub>. Structural characterization of the three coordinate copper(II) ketimide [Me<sub>3</sub>NN]Cu-N=CPh<sub>2</sub> reveals a short Cu-N<sub>ketimide</sub> distance (1.700(2) Å) with a nearly linear Cu-N-C linkage (178.9(2)°). Copper(II) ketimides [Cu<sup>II</sup>]-N=CPh<sub>2</sub> readily capture alkyl radicals R• (PhCH(•)Me and Cy•) to form the corresponding R-N=CPh<sub>2</sub> products that competes with N-N coupling of copper(II) ketimides [Cu<sup>II</sup>]-N=CPh<sub>2</sub> to form the azine Ph<sub>2</sub>C=N-N=CPh<sub>2</sub>. Copper(II) ketimides [Cu<sup>II</sup>]-N=CAr<sub>2</sub> serve as intermediates in catalytic sp<sup>3</sup> C-H amination of substrates R-H with ketimines HN=CAr<sub>2</sub> and <i><sup>t</sup></i>BuOO<i><sup>t</sup></i>Bu as oxidant to form <i>N</i>-alkyl ketimines R-N=CAr<sub>2</sub>. This protocol enables the use of unactivated sp<sup>3</sup> C-H bonds to give R-N=CAr<sub>2</sub> products easily converted to primary amines R-NH<sub>2</sub> via simple acidic deprotection.</p>

New ultrastructural findings about Borrelia burgdorferi by cryofixation, negative staining, thin sectioning and scanning techniques

1990 ◽  
Vol 48 (3) ◽  
pp. 582-583
Author(s):  
S. F. Hayes ◽  
M. D. Corwin ◽  
T. G. Schwan ◽  
D. W. Dorward ◽  
W. Burgdorfer
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Structural Characterization ◽  
Negative Staining ◽  
Low Speed ◽  
Thin Sectioning ◽  
Ultrastructural Findings

Characterization of Borrelia burgdorferi strains by means of negative staining EM has become an integral part of many studies related to the biology of the Lyme disease organism. However, relying solely upon negative staining to compare new isolates with prototype B31 or other borreliae is often unsatisfactory. To obtain more satisfactory results, we have relied upon a correlative approach encompassing a variety EM techniques, i.e., scanning for topographical features and cryotomy, negative staining and thin sectioning to provide a more complete structural characterization of B. burgdorferi.For characterization, isolates of B. burgdorferi were cultured in BSK II media from which they were removed by low speed centrifugation. The sedimented borrelia were carefully resuspended in stabilizing buffer so as to preserve their features for scanning and negative staining. Alternatively, others were prepared for conventional thin sectioning and for cryotomy using modified procedures. For thin sectioning, the fixative described by Ito, et al.

Structural characterization of the PPIase domain of FKBP51, a cochaperone of human Hsp90

2011 ◽  
Vol 44 (06) ◽  
Author(s):  
A Bracher ◽  
C Kozany ◽  
AK Thost ◽  
F Hausch
Keyword(s):  
Structural Characterization ◽  
Ppiase Domain

Structural characterization of dendrobine-type sesquiterpene alkaloids from the stems of Dendrobium nobile using LC-MS/MS

Planta Medica ◽  
2014 ◽  
Vol 80 (10) ◽  
Author(s):  
YH Wang ◽  
B Avula ◽  
N Abe ◽  
F Wei ◽  
M Wang ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Dendrobium Nobile

Structural characterization of monacolin compounds from red yeast rice by liquid chromatography and tandem mass

Planta Medica ◽  
2015 ◽  
Vol 81 (11) ◽  
Author(s):  
YH Wang ◽  
B Avula ◽  
Z Zhang ◽  
M Wang ◽  
S Sagi ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Structural Characterization ◽  
Red Yeast Rice ◽  
Tandem Mass ◽  
Red Yeast
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