Cobalt-mediated [2 + 2 + 2] cycloadditions of alkynes to the indole 2,3-double bond: an extremely facile entry into the novel 4a,9a-dihydro-9H-carbazole nucleus

1986 ◽  
Vol 108 (8) ◽  
pp. 2091-2093 ◽  
Author(s):  
Douglas B. Grotjahn ◽  
K. Peter C. Vollhardt
Keyword(s):  
Double Bond ◽  
The Novel

Porcine glutathione transferase Alpha 2-2 is a human GST A3-3 analogue that catalyses steroid double-bond isomerization

2010 ◽  
Vol 431 (1) ◽  
pp. 159-167 ◽  
Author(s):  
Natalia Fedulova ◽  
Françoise Raffalli-Mathieu ◽  
Bengt Mannervik
Keyword(s):  
Double Bond ◽  
Glutathione Transferase ◽  
Biological Species ◽  
Glutathione Transferases ◽  
Special Role ◽  
Primary Role ◽  
The Novel ◽  
Protective Function ◽  
Isomerase Activity

A primary role of GSTs (glutathione transferases) is detoxication of electrophilic compounds. In addition to this protective function, hGST (human GST) A3-3, a member of the Alpha class of soluble GSTs, has prominent steroid double-bond isomerase activity. The isomerase reaction is an obligatory step in the biosynthesis of steroid hormones, indicating a special role of hGST A3-3 in steroidogenic tissues. An analogous GST with high steroid isomerase activity has so far not been found in any other biological species. In the present study, we characterized a Sus scrofa (pig) enzyme, pGST A2-2, displaying high steroid isomerase activity. High levels of pGST A2-2 expression were found in ovary, testis and liver. In its functional properties, other than steroid isomerization, pGST A2-2 was most similar to hGST A3-3. The properties of the novel porcine enzyme lend support to the notion that particular GSTs play an important role in steroidogenesis.

The Reaction of 8-Amino-p-menthene Derivatives with Electrophiles

2004 ◽  
Vol 57 (6) ◽  
pp. 583
Author(s):  
Paul V. Bernhardt ◽  
Raymond M. Carman ◽  
Roger P. C. Derbyshire
Keyword(s):  
Double Bond ◽  
Nitrogen Atom ◽  
The Novel

Attempts to ring-close the nitrogen atom of 8-amino-p-menth-1-ene and of N-substituted 8-amino-p-menth-1-enes onto the C1–C2 double-bond carbons has led to a range of bicyclo[2.2.2] and bicyclo[3.2.1] products, together with the novel bicyclo[4.3.1]-1,3-oxazepine 9.

scholarly journals Selective Dealkenylative Functionalization of Styrenes via C-C Bond Cleavage

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jianzhong Liu ◽  
Jun Pan ◽  
Xiao Luo ◽  
Xu Qiu ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Double Bond ◽  
Late Stage ◽  
Bond Cleavage ◽  
Fine Chemicals ◽  
The Novel ◽  
Single Bond ◽  
The Past ◽  
Aryl Amines ◽  
Site Selective ◽  
Important Building Block

As a readily available feedstock, styrene with about 25 million tons of global annual production serves as an important building block and organic synthon for the synthesis of fine chemicals, polystyrene plastics, and elastomers. Thus, in the past decades, many direct transformations of this costless styrene feedstock were disclosed for the preparation of high-value chemicals, which to date, generally performed on the functionalization of styrenes through the allylic C-H bond, C(sp2)-H bond, or the C=C double bond cleavage. However, the dealkenylative functionalization of styrenes via the direct C-C single bond cleavage is so far challenging and still unknown. Herein, we report the novel and efficient C-C amination and hydroxylation reactions of styrenes for the synthesis of valuable aryl amines and phenols via the site-selective C(Ar)-C(alkenyl) single bond cleavage. This chemistry unlocks the new transformation and application of the styrene feedstock and provides an efficient protocol for the late-stage modification of substituted styrenes with the site-directed dealkenylative amination and hydroxylation.

scholarly journals Stereoselective synthesis of tetrasubstituted alkenes via a sequential carbocupration and a new sulfur–lithium exchange

2012 ◽  
Vol 8 ◽  
pp. 2202-2206 ◽  
Author(s):  
Andreas Unsinn ◽  
Cora Dunst ◽  
Paul Knochel
Keyword(s):  
Double Bond ◽  
Stereoselective Synthesis ◽  
Good Control ◽  
The Novel ◽  
Tetrasubstituted Olefins

We have designed a new sequential carbocupration and sulfur–lithium exchange that leads stereo- and regioselectively to trisubstituted alkenyllithiums. Subsequent trapping with various electrophiles yields tetrasubstituted olefins with good control of the double-bond geometry (E/Z ratio up to 99:1). The novel sulfur–lithium exchange could be extended to the stereoselective preparation of Z-styryl lithium derivatives with almost complete retention of the double-bond geometry.

A Two-Step Synthesis of a Novel 7,8-Dihydro-5,8-ethanoindolizine-6,9(5H)-dione

Synlett ◽  
2020 ◽  
Author(s):  
Luis Chacón-García ◽  
Salvador Gallardo-Alfonzo ◽  
Carlos Jesus Cortés-Garcia ◽  
Itzel Mejía-Farfán ◽  
Yliana López ◽  
...  
Keyword(s):  
Double Bond ◽  
Michael Addition ◽  
The Novel ◽  
Tetrabutylammonium Fluoride

A two-step synthesis of the novel 5,8-dimethyl-7,8-dihydro-5,8-ethanoindolizine-6,9(5H)-dione from 2,3-dimethyl-1,4-benzoquinone is described. The key step of the synthesis of this unusual fused tricyclic system is the intramolecular regiospecific aza-Michael addition of a pyrrole to an activated double bond by reaction with tetrabutylammonium fluoride under mechanochemical conditions.

scholarly journals A novel synthetic approach to hydroimidazo[1,5-b]pyridazines by the recyclization of itaconimides and HPLC–HRMS monitoring of the reaction pathway

2017 ◽  
Vol 13 ◽  
pp. 2561-2568 ◽  
Author(s):  
Dmitry Yu Vandyshev ◽  
Khidmet S Shikhaliev ◽  
Andrey Yu Potapov ◽  
Michael Yu Krysin ◽  
Fedor I Zubkov ◽  
...  
Keyword(s):  
Double Bond ◽  
Reaction Pathway ◽  
Synthetic Approach ◽  
Amino Group ◽  
The Novel ◽  
Two Stage ◽  
Intramolecular Recyclization

The novel cascade two-stage reaction between itaconimides and 1,2-diamino-4-phenylimidazole proceeds regio- and chemoselectively to form tetrahydroimidazo[1,5-b]pyridazines and includes nucleophilic C-addition by the activated C=C double bond and subsequent intramolecular recyclization of the intermediate with the amino group involved.

The novel steroidal glycoside from the dried bulb of Allium Macrostemon Bunge inhibits platelet activation

2010 ◽  
Vol 34 (8) ◽  
pp. S33-S33
Author(s):  
Wenchao Ou ◽  
Haifeng Chen ◽  
Yun Zhong ◽  
Benrong Liu ◽  
Keji Chen
Keyword(s):  
Platelet Activation ◽  
The Novel ◽  
Steroidal Glycoside ◽  
Allium Macrostemon
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