scholarly journals Direct Asymmetric Hydroxyamination Reaction Catalyzed by an Axially Chiral Secondary Amine Catalyst.

ChemInform ◽  
2006 ◽  
Vol 37 (39) ◽  
Author(s):  
Taichi Kano ◽  
Mitsuhiro Ueda ◽  
Jun Takai ◽  
Keiji Maruoka
Keyword(s):  
Secondary Amine ◽  
Axially Chiral

Direct Asymmetric Hydroxyamination Reaction Catalyzed by an Axially Chiral Secondary Amine Catalyst

2006 ◽  
Vol 128 (18) ◽  
pp. 6046-6047 ◽  
Author(s):  
Taichi Kano ◽  
Mitsuhiro Ueda ◽  
Jun Takai ◽  
Keiji Maruoka
Keyword(s):  
Secondary Amine ◽  
Axially Chiral

CONJUGATED OESTROGENS. I

1963 ◽  
Vol 43 (3) ◽  
pp. 345-360 ◽  
Author(s):  
Stanley Kushinsky ◽  
Jane (Wu) Tang
Keyword(s):  
Molecular Weight ◽  
Formic Acid ◽  
Ethyl Acetate ◽  
High Molecular Weight ◽  
Secondary Amine ◽  
Aqueous Ammonia ◽  
Organic Solution ◽  
Extraneous Material

ABSTRACT A convenient and mild procedure is described in this paper whereby free and conjugated oestrogens may be extracted from urine. The extracts containing approximately 90 per cent of the oestrogens are devoid of most of the extraneous material and may be reduced in volume to less than 1/15 of that of the urine. The procedure consists of the following steps: (1) a 10 per cent (v/v) solution of a high molecular weight secondary amine (Amberlite LA-2, Rohm and Haas) in ethyl acetate is washed with formic acid and water, (2) the oestrogens in urine (acidified to pH 2 or 3 with H2SO4) are extracted with the LA-2 solution, (3) the oestrogen fraction is back-extracted from the organic solution with dilute aqueous ammonia.

Total Synthesis of Axially-Chiral Cannabinols: A New Platform for Cannabinoid-Based Drug Discovery

2019 ◽  
Author(s):  
Primali Navaratne ◽  
Jenny Wilkerson ◽  
Kavindri Ranasinghe ◽  
Evgeniya Semenova ◽  
Lance McMahon ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Total Synthesis ◽  
Ground State ◽  
Chemical Space ◽  
Modern Medicine ◽  
The Novel ◽  
Pharmaceutical Development ◽  
Bioactive Component ◽  
Axially Chiral ◽  
New Directions

<div> <div> <div> <p>Phytocannabinoids, molecules isolated from cannabis, are gaining attention as promising leads in modern medicine, including pain management. Considering the urgent need for combating the opioid crisis, new directions for the design of cannabinoid-inspired analgesics are of immediate interest. In this regard, we have hypothesized that axially-chiral-cannabinols (ax-CBNs), unnatural (and unknown) isomers of cannabinol (CBN) may be valuable scaffolds for cannabinoid-inspired drug discovery. There are multiple reasons for thinking this: (a) ax-CBNs would have ground-state three-dimensionality akin to THC, a key bioactive component of cannabis, (b) ax-CBNs at their core structure are biaryl molecules, generally attractive platforms for pharmaceutical development due to their ease of functionalization and stability, and (c) atropisomerism with respect to phytocannabinoids is unexplored “chemical space.” Herein we report a scalable total synthesis of ax-CBNs, examine physical properties experimentally and computationally, and provide preliminary behavioral and analgesic analysis of the novel scaffolds. </p> </div> </div> </div>

Regio-, Stereo- and Enantioselective α-Addition of Carbonyl Nucleo-philes to Allenamides Catalyzed by a Synergistic Copper/Enamine System

2020 ◽  
Author(s):  
Rémi Blieck ◽  
Sebastien Lemouzy ◽  
Marc Taillefer ◽  
Florian Monnier
Keyword(s):  
Catalytic System ◽  
Secondary Amine ◽  
Primary Amine ◽  
Synergistic Catalysis ◽  
Enantioselective Addition ◽  
Amine Catalysts

A dual copper/enamine catalytic system is found to enable an intermolecular enantioselective α-addition of various carbonyl nucleophiles to allenamides. Secondary amine catalysts allowed the highly enantioselective addition of aldehydes, while using primary amine catalysts led to the enantioselective addition of ketoester nucleophiles. The process was found to be highly regio-, stereo- and enantio-selective and represented the first allene hydrofunctionalization using an synergistic catalysis involving copper

Synthesis of Axially Chiral 2,2’-Bisphosphobiarenes via a Nickel-Catalyzed Asymmetric Ullmann Coupling: General Access to Privileged Chiral Ligands without Optical Resolution

2020 ◽  
Author(s):  
Ziqing Zuo ◽  
Raphael Kim ◽  
Donald Watson
Keyword(s):  
Optical Resolution ◽  
Chiral Ligands ◽  
Chiral Auxiliaries ◽  
Axially Chiral ◽  
Ullmann Coupling

<div><p>We report an asymmetric Ullmann-type homocoupling of <i>ortho-</i>(iodo)arylphosphine oxides and <i>ortho</i>-(iodo)arylphosphonates that results in highly enantioenriched axially chiral bisphosphine oxides and bisphosphonates in good yields and excellent enantioselectivities. These products are readily converted to enantioenriched biaryl bisphosphines without need for chiral auxiliaries or optical resolution. This process provides a straightforward and practical route for the development of previously uninvestigated atroposelective biaryl bisphosphine ligands.</p></div>

Axially Chiral Bis(α-amino Acid)s and Their Deamino Analogues. Synthesis and Configurational Assignment

1998 ◽  
Vol 63 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Miloš Tichý ◽  
Luděk Ridvan ◽  
Miloš Buděšínský ◽  
Jiří Závada ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nmr Spectra ◽  
Building Blocks ◽  
X Ray Diffraction ◽  
Amino Groups ◽  
X Ray ◽  
Configurational Assignment ◽  
Symmetry Properties ◽  
Axially Chiral ◽  
Polymeric Structures

The axially chiral bis(α-amino acid)s cis-2 and trans-2 as possible building blocks for polymeric structures of novel type of helicity were prepared. Their configuration has been determined by NMR spectroscopy and, in the case of the trans-isomer, confirmed by single-crystal X-ray diffraction. Analogous pair of stereoisomeric diacids cis-3 and trans-3, devoid of the amino groups, was also prepared and their configuration assigned. The observed differences in the NMR spectra of cis- and trans-isomers of 2 and 3 are discussed from the viewpoint of their different symmetry properties.

Synthesis of N4-Substituted Derivatives of 1-[2-(Phosphonomethoxy)ethyl]cytosine and Its Diisopropyl Ester as a Model Reaction for the Synthesis of N4-Substituted Derivatives of Cidofovir

2005 ◽  
Vol 70 (12) ◽  
pp. 2066-2074 ◽  
Author(s):  
Šárka Chalupová ◽  
Antonín Holý ◽  
Milena Masojídková
Keyword(s):  
Secondary Amine ◽  
Model Reaction ◽  
Aqueous Methanol ◽  
Derivatives Of ◽  
Amine Salts

We have studied the reaction of 1-[2-(phosphonomethoxy)ethyl]cytosine (1) and its diisopropyl ester (2) with triethylammonium hydrogensulfite in 60% aqueous methanol. In the presence of some primary or secondary amine salts, at 25-70 °C, this reaction affords transaminated derivatives 4a-4e and 5a, 5b as main products accompanied by uracil compounds. However, with certain amines the reaction failed.

Effect of the number of arms on the mechanical properties of a star-shaped cyclic olefin copolymer

2019 ◽  
Vol 10 (41) ◽  
pp. 5578-5583 ◽  
Author(s):  
Takumitsu Kida ◽  
Ryo Tanaka ◽  
Koh-hei Nitta ◽  
Takeshi Shiono
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Physical Properties ◽  
Secondary Amine ◽  
Aggregation Number ◽  
Drastic Change ◽  
Cyclic Olefin Copolymer ◽  
Cyclic Olefin

The increase of aggregation number in a star-shaped cyclic olefin copolymer was succeeded by using a triazine-based secondary amine, which caused a drastic change in physical properties without changing the thermal properties.

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