Synthesis of progesterone derivatives and evaluation of their efficiency as pneumococcal vaccines

Mohareb, Rafat M.; Farouk, Fatma Omar Al; Sherif, Sherif M.; Karaghiosoff, Konstantin

doi:10.1007/s00044-013-0894-8

Cited by 7 publications

(4 citation statements)

References 26 publications

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“…[1] Aldol and Knoevenagel condensation reactions share a common electrophile: aldehydes, and due to the lower acidity of Knoevenagel nucleophiles, e. g., βdiketones, malonate esters, etc., precedent exists for Knoevenagel product formation in the presence of a ketone but not vice versa. [2] Both of these reactions can be catalyzed by amino acids, however the catalytic role of the amine in each reaction is different. [3,4] We consequently hypothesized that exploitation of this fact could permit a new type of chemoselectivity to be identified.…”

Section: Introductionmentioning

confidence: 99%

Harnessing Additional Capability from in Water Reaction Conditions: Aldol versus Knoevenagel Chemoselectivity

et al. 2021

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Aldol reaction chemoselectivity, racemic or enantioselective, has not been previously demonstrated in the presence of Knoevenagel active functional groups. Here, we show that unhindered β-diketones remain unreacted while a ketone moiety undergoes a highly enantioselective aldol desymmetrization resulting in three new stereogenic centers using in water reaction conditions. A mechanistic hypothesis for the chemoselective formation of either aldol or Knoevenagel products is presented. It elucidates how these amino acid catalyzed reactions completely suppress formation of the expected Knoevenagel product under in water (heterogeneous) reaction conditions, but not when water is present as a dissolved cosolvent (homogeneous). Finally, the developed hypothesis reinforces and expands the role of water at an organic-water interface.

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Section: Introductionmentioning

confidence: 99%

Harnessing Additional Capability from in Water Reaction Conditions: Aldol versus Knoevenagel Chemoselectivity

et al. 2021

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“…When progesterone was used as substrate in the Gewald synthesis with either ethyl cyanoacetate or malononitrile as the active methylene component, two 2-aminothiophenes 86 (Figure 10) were obtained. [94] Their evaluation against different serotypes of S.…”

Section: Antimicrobial Agents With An Unsubstituted 2-aminothiophene ...mentioning

confidence: 99%

“…When progesterone was used as substrate in the Gewald synthesis with either ethyl cyanoacetate or malononitrile as the active methylene component, two 2‐aminothiophenes 86 (Figure 10) were obtained. [ 94 ] Their evaluation against different serotypes of S. pneumoniae clinical isolates using the agar microdilution method showed that compound 86 (R = CN) was very active against two isolates and moderately active against other two isolates.…”

Section: Aminothiophenes As Scaffolds For Antimicrobial Agentsmentioning

confidence: 99%

Thiophene‐containing compounds with antimicrobial activity

Roman¹

2022

Archiv der Pharmazie

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Thiophene, as a member of the group of five-membered heterocycles containing one heteroatom, is one of the simplest heterocyclic systems. Many synthetic strategies allow the accurate positioning of various functionalities onto the thiophene ring. This review provides a comprehensive, systematic and detailed account of the developments in the field of antimicrobial compounds featuring at least one thiophene ring in their structure, over the last decade.

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“…Knoevenagel pronucleophiles, most often methylene units flanked by two electron withdrawing groups (EWG), can be converted to their nucleophilic forms under acidic, neutral, or basic conditions [ 13 , 14 ]. Furthermore, their significantly lower pK a values, as compared to ketones, allow them to chemoselectively undergo Knoevenagel reactions in the presence of ketones [ 15 , 16 , 17 ]. Further supportive evidence of the greater reactivity of Knoevenagel versus aldol (ketone) nucleophiles comes from the literature reports on the amino acid catalyzed variants.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective Catalytic Aldol Reactions in the Presence of Knoevenagel Nucleophiles: A Chemoselective Switch Optimized in Deep Eutectic Solvents Using Mechanochemistry

Al Beiruty,

Zhylinska,

Kutateladze

et al. 2023

Molecules

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In the presence of different nucleophilic Knoevenagel competitors, cyclic and acyclic ketones have been shown to undergo highly chemoselective aldol reactions with aldehydes. In doing so, the substrate breadth for this emerging methodology has been significantly broadened. The method is also no longer beholden to proline-based catalyst templates, e.g., commercially available O-t-Bu-L-threonine is advantageous for acyclic ketones. The key insight was to exploit water-based mediums under conventional (in-water) and non-conventional (deep eutectic solvents) conditions. With few exceptions, high aldol-to-Knoevenagel chemoselectivity (>10:1) and good product profiles (yield, dr, and ee) were observed, but only in DESs (deep eutectic solvents) in conjunction with ball milling did short reaction times occur.

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Synthesis of progesterone derivatives and evaluation of their efficiency as pneumococcal vaccines

Cited by 7 publications

References 26 publications

Harnessing Additional Capability from in Water Reaction Conditions: Aldol versus Knoevenagel Chemoselectivity

Harnessing Additional Capability from in Water Reaction Conditions: Aldol versus Knoevenagel Chemoselectivity

Thiophene‐containing compounds with antimicrobial activity

Enantioselective Catalytic Aldol Reactions in the Presence of Knoevenagel Nucleophiles: A Chemoselective Switch Optimized in Deep Eutectic Solvents Using Mechanochemistry

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