Long-Range Effect of 17-Substituents in 3-Oxo Steroids on 4,5-Double Bond Hydrogenation

1998 ◽  
Vol 63 (10) ◽  
pp. 1528-1542 ◽  
Author(s):  
Romana Šídová ◽  
Karel Stránský ◽  
Alexander Kasal ◽  
Barbora Slavíková ◽  
Ladislav Kohout
Keyword(s):  
Acetic Acid ◽  
Double Bond ◽  
Carboxylic Acids ◽  
Chain Length ◽  
Long Range ◽  
Alkyl Chain ◽  
Platinum Catalyst ◽  
Alkyl Chain Length ◽  
Range Effect ◽  
Bond Hydrogenation

The long-range effect of substituents in the 17-position on the hydrogenation of double bond of the steroidal ∆4-3-ketones in acetic acid on a platinum catalyst is described in a series of testosterone (1) and epitestosterone (5) esters with carboxylic acids of varying alkyl chain length. The ratio 5α- to 5β-products is affected by the nature of substituents in the position 17.

Synthesis of Steroid O-(ω-Hydroxyalkyl)oximes by Reduction of Corresponding O-(ω-Carboxyalkyl)oxime Derivatives

1998 ◽  
Vol 63 (4) ◽  
pp. 557-576 ◽  
Author(s):  
Tereza Slavíková ◽  
Vladimír Pouzar ◽  
Ivan Černý
Keyword(s):  
Carboxylic Acids ◽  
Chain Length ◽  
Sodium Borohydride ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Side Product ◽  
Unexpected Reaction ◽  
Mixed Anhydrides ◽  
Oxime Derivatives

Steroid O-(ω-hydroxyalkyl)oximes with varying alkyl chain length were prepared from the corresponding carboxylic acids using the reduction of mixed anhydrides with sodium borohydride. An unexpected reaction course was observed with O-(2-carboxyethyl)oximes of 3-oxo-4-ene steroids, where a 4,5-dihydroisoxazol-3(2H)-one derivative was formed as a side product.

scholarly journals Influence of alkyl chain length on sulfated zirconia catalysed batch and continuous esterification of carboxylic acids by light alcohols

2016 ◽  
Vol 18 (20) ◽  
pp. 5529-5535 ◽  
Author(s):  
Amin Osatiashtiani ◽  
Lee J. Durndell ◽  
Jinesh C. Manayil ◽  
Adam F. Lee ◽  
Karen Wilson
Keyword(s):  
Liquid Phase ◽  
Carboxylic Acids ◽  
Chain Length ◽  
Sulfated Zirconia ◽  
Solid Acid ◽  
Alkyl Chain ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Alkyl Chain Length ◽  
Highly Dispersed

Sulfated zirconia in pure and highly dispersed form is a tunable and effective solid acid catalyst for the batch and continuous liquid phase esterification of carboxylic acids.

scholarly journals Silver Nanoparticles Stabilized with Phosphorus-Containing Heterocyclic Surfactants: Synthesis, Physico-Chemical Properties, and Biological Activity Determination

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1883
Author(s):  
Martin Pisárčik ◽  
Miloš Lukáč ◽  
Josef Jampílek ◽  
František Bilka ◽  
Andrea Bilková ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Biological Activity ◽  
Zeta Potential ◽  
Chain Length ◽  
Alkyl Chain ◽  
Chemical Properties ◽  
Alkyl Chain Length ◽  
Microbial Pathogens ◽  
Physico Chemical ◽  
Phosphorus Containing

Phosphorus-containing heterocyclic cationic surfactants alkyldimethylphenylphospholium bromides with the alkyl chain length 14 to 18 carbon atoms were used for the stabilization of silver nanodispersions. Zeta potential of silver nanodispersions ranges from +35 to +70 mV, which indicates the formation of stable silver nanoparticles (AgNPs). Long-chain heptadecyl and octadecyl homologs of the surfactants series provided the most intensive stabilizing effect to AgNPs, resulting in high positive zeta potential values and smaller diameter of AgNPs in the range 50–60 nm. A comparison with non-heterocyclic alkyltrimethylphosphonium surfactants of the same alkyl chain length showed better stability and more positive zeta potential values for silver nanodispersions stabilized with heterocyclic phospholium surfactants. Investigations of biological activity of phospholium-capped AgNPs are represented by the studies of antimicrobial activity and cytotoxicity. While cytotoxicity results revealed an increased level of HepG2 cell growth inhibition as compared with the cytotoxicity level of silver-free surfactant solutions, no enhanced antimicrobial action of phospholium-capped AgNPs against microbial pathogens was observed. The comparison of cytotoxicity of AgNPs stabilized with various non-heterocyclic ammonium and phosphonium surfactants shows that AgNPs capped with heterocyclic alkyldimethylphenylphospholium and non-heterocyclic triphenyl-substituted phosphonium surfactants have the highest cytotoxicity among silver nanodispersions stabilized by the series of ammonium and phosphonium surfactants.

scholarly journals Physico-chemical and gel properties of heat-induced pasteurized liquid egg white gel: effect of alkyl chain length of alcohol

2021 ◽  
Vol 24 (1) ◽  
pp. 1229-1243
Author(s):  
Danai Charoensuk ◽  
Robert G. Brannan ◽  
Wilailuk Chaiyasit ◽  
Wanlop Chanasattru
Keyword(s):  
Chain Length ◽  
Alkyl Chain ◽  
Egg White ◽  
Alkyl Chain Length ◽  
Gel Properties ◽  
Gel Effect ◽  
Physico Chemical
Sign in / Sign up

Export Citation Format

Share Document