Synthesis of the novel conjugated ω,ω′-diaryl/heteroaryl hexatriene system with the central double bond in a heteroaromatic ring: photochemical transformations of 2,3-divinylfuran derivatives

Tetrahedron ◽  
2006 ◽  
Vol 62 (31) ◽  
pp. 7396-7407 ◽  
Author(s):  
Irena Škorić ◽  
Ivana Flegar ◽  
Željko Marinić ◽  
Marija Šindler-Kulyk
2010 ◽  
Vol 431 (1) ◽  
pp. 159-167 ◽  
Author(s):  
Natalia Fedulova ◽  
Françoise Raffalli-Mathieu ◽  
Bengt Mannervik

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.


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

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.


1964 ◽  
Vol 42 (1) ◽  
pp. 79-83 ◽  
Author(s):  
George Just ◽  
Clifford C. Leznoff

The photolysis of 3-alkoxycholesta-3,5-dienes in an alcohol has been found to result in a stereospecific addition of the alcohol to the Δ3 double bond with formation of β,γ-unsaturated ketals. On silica gel, the non-cyclic β,γ-unsaturated ketals gave cholest-5-en-3-one.


Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jianzhong Liu ◽  
Jun Pan ◽  
Xiao Luo ◽  
Xu Qiu ◽  
Cheng Zhang ◽  
...  

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.


2012 ◽  
Vol 8 ◽  
pp. 2202-2206 ◽  
Author(s):  
Andreas Unsinn ◽  
Cora Dunst ◽  
Paul Knochel

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.


Synlett ◽  
2020 ◽  
Author(s):  
Luis Chacón-García ◽  
Salvador Gallardo-Alfonzo ◽  
Carlos Jesus Cortés-Garcia ◽  
Itzel Mejía-Farfán ◽  
Yliana López ◽  
...  

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.


2017 ◽  
Vol 13 ◽  
pp. 2561-2568 ◽  
Author(s):  
Dmitry Yu Vandyshev ◽  
Khidmet S Shikhaliev ◽  
Andrey Yu Potapov ◽  
Michael Yu Krysin ◽  
Fedor I Zubkov ◽  
...  

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.


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