Discovery-Oriented Approach To Organic Synthesis: Tandem Aldol Condensation-Michael Addition Reactions. Identifying Diastereotopic Hydrogens in an Achiral Molecule by NMR Spectroscopy

2001 ◽  
Vol 78 (9) ◽  
pp. 1264 ◽  
Author(s):  
Nanette Wachter-Jurcsak ◽  
Kendra Reddin
Keyword(s):  
Nmr Spectroscopy ◽  
Organic Synthesis ◽  
Michael Addition ◽  
Aldol Condensation ◽  
Addition Reactions ◽  
Oriented Approach

Organo-catalysis as emerging tools in organic synthesis: aldol and Michael reactions

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Nagaraju Kerru ◽  
Suresh Maddila ◽  
Sreekantha B. Jonnalagadda
Keyword(s):  
Organic Synthesis ◽  
Michael Addition ◽  
Addition Reactions ◽  
Chiral Molecules ◽  
Asymmetric Aldol ◽  
Bond Forming ◽  
Michael Reactions ◽  
Stereogenic Centers ◽  
Synthetic Hybrids ◽  
The Impact

Abstract Organocatalysis has occupied sustainable position in organic synthesis as a powerful tool for the synthesis of enantiomeric-rich compounds with multiple stereogenic centers. Among the various organic molecules for organocatalysis, the formation of carbon–carbon is viewed as a challenging issue in organic synthesis. The asymmetric aldol and Michael addition reactions are the most significant methods for C–C bond forming reactions. These protocols deliver a valuable path to access chiral molecules, which are useful synthetic hybrids in biologically potent candidates and desirable versatile pharmaceutical intermediates. This work highlighted the impact of organocatalytic aldol and Michael addition reactions in abundant solvent media. It focused on the crucial methods to construct valuable molecules with high enantio- and diastereo-selectivity.

scholarly journals ULTRASOUND-ASSISTED SYNTHESIS OF NOVEL 3-(PYRIDINYLAMINO)-1-FERROCENYLPROPAN-1-ONES

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Aleksandra Minić Jančić ◽  
Danijela Ilić Komatina ◽  
Anka Todosijević ◽  
Dragana Stevanović
Keyword(s):  
Nmr Spectroscopy ◽  
Organic Synthesis ◽  
Ultrasonic Irradiation ◽  
Michael Addition ◽  
Mannich Bases ◽  
Detailed Characterization ◽  
Ir And Nmr Spectroscopy ◽  
Elemental Analyses ◽  
Ultrasound Assisted

In this work we will report the formulation of novel 3-(pyridinylamino)-1-ferrocenylpropan-1-ones. A fruitful aza-Michael addition of pyridinamine moiety to a conjugated enone, 1-ferrocenylpropenone, has been accomplished by an ultrasonic irradiation of the mixture of these reactants. As the catalyst montmorillonite K-10 has been used and the reaction has been carried out as solvent-free, yielding ferrocene containing Mannich bases, compounds considered as important precursors in organic synthesis. The reaction score has been evaluated on three examples. The prepared products have been purified by column chromatography. In addition, a detailed characterization of the obtained 3-(pyridin-2-ylamino)-1-ferrocenylpropan-1-on and 3-(pyridin-3-ylamino)-1-ferrocenylpropan-1-on has been completed by IR and NMR spectroscopy, as well as elemental analyses.

Antioxidant properties of certain C5 substituted 4-arylimino-thiazolidin-2-ones

2020 ◽  
Vol 26 (4) ◽  
pp. 62-71
Author(s):  
Z.I. Chulovska ◽  
◽  
I.V. Drapak ◽  
U.B. Chulovska ◽  
◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Nmr Spectroscopy ◽  
Organic Synthesis ◽  
Elemental Analysis ◽  
Aldol Condensation ◽  
Azo Coupling ◽  
Dpph Radical ◽  
Condensation Reactions ◽  
Study Results ◽  
Aldol Condensation Reactions

Aim. Expanding the synthetic potential of 4-arylimino-thiazolidin-2-ones; a study of reactivity; and primary screening for antioxidant activity of synthesized compounds. Materials and Methods. All chemicals were of analytical grade and commercially available. When performing the synthetic part of the work, reagents manufactured by Merck (Germany) and Sigma-Aldrich (USA) were used. All the reagents and solvents were used without further purification and drying. Methods of organic synthesis, physical and physical-chemical methods of analysis of organic compounds (NMR spectroscopy, elemental analysis) were used in the study. Results and Discussions. The peculiar pharmacological activities of 4-iminothiazolidin-2-ones prompted us to synthesize certain С5 substituted 4-arylimino-thiazolidin-2-ones and test them for antioxidant activity. The specified scaffold represents a convenient intermediate in order to afford С5 substituteds 4-arylimino-thiazolidin-2-ones. The active methylene group presence in C5 position of the basic scaffold provides an entry for its utilization in azo coupling and aldol condensation reactions leading to appropriate 5-aryl-hydrazono and 5-arylidene derivatives of 4-arylimino-thiazolidin-2-one generation. The structures of the obtained compounds were confirmed by 1H NMR spectroscopy and elemental analysis. The spectroscopic data of all compounds correspond to the proposed structures. The antioxidant activity of the synthesized compounds was measured in vitro by the method of scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. DPPH radical found many applications due to its high stability in a methanolic solution and intense purple color. In its oxidized form, the DPPH radical has an absorbance maximum at a wavelength of 517 nm. For the first time, antioxidant activity was identified among С5 substituted 4-arylimino-thiazolidin-2-ones. Conclusions. Based on azo coupling and aldol condensation reactions, structural modification of the C5 position of certain 4-arylimino-thiazolidin-2-ones was conducted. For all synthesized compounds, primary pharmacological screening for antioxidant activity was performed. Three highly active compounds with a pronounced antioxidant effect have been identified, which approach or exceed ascorbic acid in terms of activity. Key words: organic synthesis, 4-arylimino-thiazolidin-2-ones, 2,2-diphenyl-1-picrylhydrazyl, antioxidant activity

Benzothiazines in Organic Synthesis. Stereoselectivity in the Intermolecular Michael Addition Reactions of Benzothiazines

2007 ◽  
Vol 9 (23) ◽  
pp. 4701-4704 ◽  
Author(s):  
Michael Harmata ◽  
Yugang Chen ◽  
Charles L. Barnes
Keyword(s):  
Organic Synthesis ◽  
Michael Addition ◽  
Addition Reactions

Thia-Michael Addition Reactions in Water Using 3-[Bis(Alkylthio) Methylene] Pentane-2,4-Diones as Odorless and Efficient Thiol Equivalents

2007 ◽  
Vol 4 (4) ◽  
pp. 281-284 ◽  
Author(s):  
Yanyan Chai ◽  
Dewen Dong ◽  
Yan Ouyang ◽  
Yongjiu Liang ◽  
Yan Wang ◽  
...  
Keyword(s):  
Michael Addition ◽  
Addition Reactions

scholarly journals Recoverable Phospha-Michael Additions Catalyzed by a 4-N,N-Dimethylaminopyridinium Saccharinate Salt or a Fluorous Long-Chained Pyridine: Two Types of Reusable Base Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1159
Author(s):  
Eskedar Tessema ◽  
Vijayanath Elakkat ◽  
Chiao-Fan Chiu ◽  
Jing-Hung Zheng ◽  
Ka Long Chan ◽  
...  
Keyword(s):  
Michael Addition ◽  
Polar Solvent ◽  
Addition Reaction ◽  
High Yield ◽  
Addition Reactions ◽  
Polar Solvents ◽  
Unsaturated Bond ◽  
Base Catalysts ◽  
Michael Additions

Phospha-Michael addition, which is the addition reaction of a phosphorus-based nucleophile to an acceptor-substituted unsaturated bond, certainly represents one of the most versatile and powerful tools for the formation of P-C bonds, since many different electrophiles and P nucleophiles can be combined with each other. This offers the possibility to access many diversely functionalized products. In this work, two kinds of basic pyridine-based organo-catalysts were used to efficiently catalyze phospha-Michael addition reactions, the 4-N,N-dimethylaminopyridinium saccharinate (DMAP·Hsac) salt and a fluorous long-chained pyridine (4-Rf-CH2OCH2-py, where Rf = C11F23). These catalysts have been synthesized and characterized by Lu’s group. The phospha-Michael addition of diisopropyl, dimethyl or triethyl phosphites to α, β-unsaturated malonates in the presence of those catalysts showed very good reactivity with high yield at 80–100 °C in 1–4.5 h with high catalytic recovery and reusability. With regard to significant catalytic recovery, sometimes more than eight cycles were observed for DMAP·Hsac adduct by using non-polar solvents (e.g., ether) to precipitate out the catalyst. In the case of the fluorous long-chained pyridine, the thermomorphic method was used to efficiently recover the catalyst for eight cycles in all the reactions. Thus, the easy separation of the catalysts from the products revealed the outstanding efficacy of our systems. To our knowledge, these are good examples of the application of recoverable organo-catalysts to the DMAP·Hsac adduct by using non-polar solvent and a fluorous long-chained pyridine under the thermomorphic mode in phospha-Michael addition reactions.

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