Synthesis of acetylenedicarboxylic acid esters and asymmetric Diels–Alder reactions of the bis(methyl (S)-lactyl) ester

1995 ◽  
Vol 73 (9) ◽  
pp. 1454-1462 ◽  
Author(s):  
James L. Charlton ◽  
Gaiklean Chee ◽  
Heather McColeman
Keyword(s):  
Diels Alder ◽  
Asymmetric Induction ◽  
Hydroxyl Group ◽  
Acetylenedicarboxylic Acid ◽  
Chiral Esters ◽  
Acid Esters ◽  
General Method

A general method has been developed for the preparation of acetylenedicarboxylic acid esters and applied to the synthesis of both achiral and chiral esters. Diels–Alder reactions of one of the chiral esters, the bis(methyl (S)-lactyl) ester, with various types of dienes, such as phenylbutadiene, orthoquinodimethanes, and isobenzofuran, have been investigated. Moderate asymmetric induction was observed in reactions with dienes bearing an α-hydroxyl group. In one case, an unusual solvent-induced reversal of asymmetric induction was observed. Keywords: acetylenedicarboxylic acid esters, phenylbutadiene, orthoquinodimethanes, isobenzofurans, Diels–Alder, asymmetric.

α-Glucosidase Inhibition and Docking Studies of 5-Deoxyflavonols and Dihydroflavonols Isolated from Abutilon pakistanicum

2019 ◽  
Vol 23 (17) ◽  
pp. 1857-1866
Author(s):  
Munawar Hussain ◽  
Zaheer Ahmed ◽  
Shamsun N. Khan ◽  
Syed A. A. Shah ◽  
Rizwana Razi ◽  
...  
Keyword(s):  
Methanolic Extract ◽  
Docking Studies ◽  
Hydroxyl Group ◽  
Coumaric Acid ◽  
In Vitro Activity ◽  
Aerial Parts ◽  
First Time ◽  
Acid Esters ◽  
Phenol Moiety

Three new 5-deoxyflavonoid and dihydroflavonoids 2, 3 and 4 have been isolated from the methanolic extract of Abutioln pakistanicum aerial parts, for which structures were elucidated explicitly by extensive MS- and NMR-experiments. In addition to these, 3,7,4′-trihydroxy-3′-methoxy flavonol (1) is reported for the first time from Abutioln pakistanicum. Compound 2 and 4 are p-coumaric acid esters while compounds 2–4 exhibited α-glucosidase inhibitory activity. Docking studies indicated that the ability of flavonoids 2, 3 and 4 to form multiple hydrogen bonds with catalytically important residues is decisive hence is responsible for the inhibition activity. The docking results signified the observed in-vitro activity quite well which is in accordance with previously obtained conclusion that phenol moiety and hydroxyl group are critical for the inhibition of α-glucosidase enzyme.

The synthesis of trisubstituted cyclopentadienes and their reactivity in the intramolecular Diels–Alder reaction

1984 ◽  
Vol 62 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Sandra J. Alward ◽  
Alex G. Fallis
Keyword(s):  
Adverse Effect ◽  
Alder Reaction ◽  
Diels Alder ◽  
Keto Ester ◽  
Diels Alder Reaction ◽  
General Method

The intramolecular Diels–Alder reactivity of several trisubstituted cyclopentadienes is described and a general method for their preparation reported. In general, sidechain keto-ester functionality has an adverse effect on these internal cycloadditions.

scholarly journals The Search for Biologically Active Compounds in the Series of N-ethoxyethylpiperidine Derivatives

2019 ◽  
Vol 21 (2) ◽  
pp. 125
Author(s):  
U.B. Issayeva ◽  
G.S. Akhmetova ◽  
U.M. Datkhayev ◽  
M.T. Omyrzakov ◽  
K.D. Praliyev ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Biologically Active ◽  
Hydroxyl Group ◽  
Diffusion Method ◽  
Acylation Reaction ◽  
Gram Positive Bacteria ◽  
Cyclopropanecarboxylic Acid ◽  
Yeast Fungus ◽  
Acid Esters

With the aim to introduce fragment of cyclopropane and fragments of p-, m-, o-fluorophenyls into the structures of N-ethoxyethylpiperidines, acylation of oxime and phenylacetylenic alcohol of 1-(2-ethoxyethyl)-4-ketopiperidine by cyclopropanecarbonylchloride was carried out; on the basis of 1-(2-ethoxyethyl)-4-ethynyl-4-hydroxypiperidine (cascaine alcohol), acylation by 4-fluoro-, 3-fluoro-, 2-fluorobenzoylchlorides was carried out with formation of the corresponding piperidine containing hydrochlorides of cyclopropanecarboxylic acid esters and para-, meta-, ortho-fluorobenzoic esters. Acylation reaction on the hydroxyl group of compounds is carried out in absolute dioxane, the acylating agents are cyclopropanecarbonylchloride, p-, m-, o-fluorobenzoyl chlorides taken in excess. The obtained esters of cyclopropanecarboxylic and para-, meta-, ortho-fluorobenzoic acids are crystalline substances with a clear melting point, well soluble in water, ethanol, acetone. P-fluorobenzoates are obtained with better yields, m-fluorobenzoates occupy an intermediate position, and o-fluorobenzoates are formed with the lowest yields. The best yields of fluorobenzoates are obtained using dioxane as a solvent. Para-, meta-, ortho-fluorobenzoic esters of 1-(2-ethoxyethyl)-4-ethynyl-4-hydroxypiperidine coded A-4 – A-6 were studied for the presence of antimicrobial activity, the actions of these preparations were evaluated in vitro in relation to strains of gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, gram-negative strains of Escheriсhia coli, Pseudomonas aeruginosa and to yeast fungus Сandida albicans by the diffusion method into agar (holes). Introduction of fluorine atom into the structure of cascaine lead to manifestation of antimicrobial activity.

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