scholarly journals Synthesis of 2-Oxazolines from Ring Opening Isomerization of 3-Amido-2-Phenyl Azetidines

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 857
Author(s):  
Xin Zhou ◽  
Baiyi Mao ◽  
Zhanbin Zhang
Keyword(s):  
Carboxylic Acid ◽  
Asymmetric Catalysis ◽  
Amino Alcohol ◽  
Lewis Acids ◽  
Ring Opening ◽  
Building Blocks ◽  
Efficient Synthesis

Chiral 2-oxazolines are valuable building blocks and famous ligands for asymmetric catalysis. The most common synthesis involves the reaction of an amino alcohol with a carboxylic acid. In this paper, an efficient synthesis of 2-oxazolines has been achieved via the stereospecific isomerization of 3-amido-2-phenyl azetidines. The reactions were studied in the presence of both Brønsted and Lewis acids, and Cu(OTf)2 was found to be the most effective.

Design, synthesis and evaluation of structurally diverse ortho-acylphenol-diindolylmethane hybrids as anticancer agents

2022 ◽  
Author(s):  
Zhi-Gang Yin ◽  
Xiong-Wei Liu ◽  
Hui-Juan Wang ◽  
Min Zhang ◽  
Xiong-Li Liu ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Anticancer Agents ◽  
Nucleophilic Addition ◽  
Ring Opening ◽  
Building Blocks ◽  
Efficient Synthesis ◽  
Design Synthesis ◽  
Pyrone Ring ◽  
Ring Opening Reaction ◽  
First Time

A highly efficient synthesis of structurally diverse ortho-acylphenol–diindolylmethane hybrids 3 using carboxylic acid-activated chromones as versatile synthetic building blocks is reported here for the first time, through 1,4-nucleophilic addition and followed by a decarboxylation and pyrone ring opening reaction process.

scholarly journals SnCl4-catalyzed Solvent-free Acetolysis of 2,7-Anhydrosialic Acid Derivatives

2019 ◽  
Author(s):  
Kesatebrhan Haile Asressu ◽  
Cheng-Chung Wang
Keyword(s):  
Sialic Acid ◽  
Lewis Acids ◽  
Ring Opening ◽  
Building Blocks ◽  
Solvent Free ◽  
Biologically Active ◽  
Protecting Group ◽  
Free Ring ◽  
Ring Opening Reactions ◽  
Acid Catalyzed

Sialic acid-containing glycans are found in different sialic acid forms and a variety of glycosidic linkages in biologically active glycoconjugates. Hence, the preparation of suitably protected sialyl building blocks requires high attention in order to access glycans in pure form. In this line, various C-5 substituted 2,7-anhydrosialic acid derivatives bearing both electron donating and withdrawing protecting groups were synthesized and subjected to different Lewis acid-catalyzed solvent free ring opening reactions at room temperature in the presence of acetic anhydride. Among the various Lewis acids tested, the desired acetolysized products were obtained in moderate yields under a tin(IV) chloride catalysis system. Our methodology can be extended to regioselective protecting group installation and manipulation towards a number of thiosialoside and halide donors.

scholarly journals Exploring chemical diversity via a modular reaction pairing strategy

2012 ◽  
Vol 8 ◽  
pp. 1293-1302 ◽  
Author(s):  
Joanna K Loh ◽  
Sun Young Yoon ◽  
Thiwanka B Samarakoon ◽  
Alan Rolfe ◽  
Patrick Porubsky ◽  
...  
Keyword(s):  
Amino Alcohol ◽  
Building Blocks ◽  
Chemical Diversity ◽  
Nucleophilic Aromatic Substitution ◽  
Mitsunobu Reaction ◽  
Aromatic Substitution ◽  
Efficient Synthesis ◽  
Microwave Assisted ◽  
Computational Analyses ◽  
Pairing Protocol

The efficient synthesis of an 80-member library of unique benzoxathiazocine 1,1-dioxides by a microwave-assisted, intermolecular nucleophilic aromatic substitution (SNAr) diversification pathway is reported. Eight benzofused sultam cores were generated by means of a sulfonylation/SNAr/Mitsunobu reaction pairing protocol, and subsequently diversified by intermolecular SNAr with ten chiral, non-racemic amine/amino alcohol building blocks. Computational analyses were employed to explore and evaluate the chemical diversity of the library.

scholarly journals Controlled Ring-Opening Polymerization of N-(3-tert-Butoxy-3-oxopropyl) Glycine Derived N-Carboxyanhydrides towards Well-defined Peptoid-based Polyacids

2021 ◽  
Author(s):  
Donghui Zhang ◽  
Bailee Barrett ◽  
Garrett Sternhagen
Keyword(s):  
Carboxylic Acid ◽  
Ring Opening ◽  
Building Blocks ◽  
Ring Opening Polymerization ◽  
Supramolecular Assemblies ◽  
Stimuli Responsive ◽  
Carboxylic Acid Groups

Polypeptoids bearing carboxylic acid groups on the N-substituent are useful building blocks for the construction of peptidomimetic supramolecular assemblies with stimuli-responsive properties. Towards this end, N-(3-tert-butoxy-3-oxopropyl) glycine derived N-carboxyanhydride (tBuO2Pr-NCA)...

scholarly journals Synthesis of a potential bendamustine deschloro dimer impurity

2020 ◽  
pp. 174751982094593
Author(s):  
Jie Yuan ◽  
Hai-Bin Zhu
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Carboxylic Acid ◽  
Ring Opening ◽  
High Performance ◽  
Efficient Synthesis ◽  
Carboxylic Acid Groups ◽  
Ring Opening Reaction ◽  
Hydrolysis Of

Bendamustine deschloro dimer was considered as a potential impurity in bendamustine hydrochloride resulting from the hydrolysis of bendamustine followed by intermolecular esterification. An efficient synthesis of bendamustine deschloro dimer was achieved from 4-(5-amino-1-methyl-1H-benzo[d]imidazol-2-yl)butanoate involving nine sequential steps including benzyl-protection/deprotection of the amine and carboxylic acid groups, saponification, ring-opening reaction of oxirane as well as Fischer/Steglish esterfication and so on. The target bendamustine deschloro dimer was obtained using a high-performance liquid chromatography in a purity of 95.63%.

scholarly journals Efficient Synthesis Of 5-Substituted Ethyl 1,2,4-Triazole-3-Carboxylates

2016 ◽  
Vol 4 (2) ◽  
pp. 28-32 ◽  
Author(s):  
Dmytro Khomenko ◽  
Roman Doroschuk ◽  
Rostyslav Lampeka
Keyword(s):  
Carboxylic Acid ◽  
Organic Synthesis ◽  
Building Blocks ◽  
Efficient Synthesis

Easily accessible carboxylic acid hydrazides undergo cyclocondensation with ethyl carbethoxyformimidate, giving 5-substituted ethyl 1,2,4-triazole-3-carboxylates. These are important building blocks in organic synthesis. The approach we used to obtain title compounds made possible synthesis of 3-(2-aminophenyl)-1,2,4-triazole.

Asymmetric catalysis in aqueous media

2007 ◽  
Vol 79 (2) ◽  
pp. 235-245 ◽  
Author(s):  
Shū Kobayashi
Keyword(s):  
Asymmetric Catalysis ◽  
Lewis Acids ◽  
Ring Opening ◽  
Acid Catalysis ◽  
Aqueous Media ◽  
Asymmetric Reactions ◽  
Epoxide Ring ◽  
Mild Conditions ◽  
Ring Opening Reactions ◽  
Bipyridine Ligand

Lewis acid catalysis has attracted much attention in organic synthesis because of unique reactivity and selectivity attained under mild conditions. Although various kinds of Lewis acids have been developed and applied in industry, these Lewis acids must be generally used under strictly anhydrous conditions. The presence of even a small amount of water handles the reactions owing to preferential reactions of the Lewis acids with water rather than the substrates. In contrast, rare earth and other metal complexes have been found to be water-compatible. Several catalytic asymmetric reactions in aqueous media, including hydroxymethylation of silicon enolates with an aqueous solution of formaldehyde in the presence of Sc(OTf)3-chiral bipyridine ligand or Bi(OTf)3-chiral bipyridine ligand, Sc- or Bi-catalyzed asymmetric meso-epoxide ring-opening reactions with amines, and asymmetric Mannich-type reactions of silicon enolates with N-acylhydrazones in the presence of a chiral Zn catalyst have been developed. Water plays key roles in these asymmetric reactions.

scholarly journals SnCl4-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives

2019 ◽  
Vol 15 ◽  
pp. 2990-2999
Author(s):  
Kesatebrhan Haile Asressu ◽  
Cheng-Chung Wang
Keyword(s):  
Sialic Acid ◽  
Lewis Acids ◽  
Ring Opening ◽  
Building Blocks ◽  
Solvent Free ◽  
Biologically Active ◽  
Protecting Group ◽  
Free Ring ◽  
Ring Opening Reactions ◽  
Acid Catalyzed

Sialic acid-containing glycans are found in different sialic acid forms and a variety of glycosidic linkages in biologically active glycoconjugates. Hence, the preparation of suitably protected sialyl building blocks requires high attention in order to access glycans in a pure form. In line with this, various C-5-substituted 2,7-anhydrosialic acid derivatives bearing both electron-donating and -withdrawing protecting groups were synthesized and subjected to different Lewis acid-catalyzed solvent-free ring-opening reactions at room temperature in the presence of acetic anhydride. Among the various Lewis acids tested, the desired acetolysis products were obtained in moderate yields under tin(IV) chloride catalysis. Our methodology could be extended to regioselective protecting group installations and manipulations towards a number of thiosialoside and halide donors.

Adventures and Detours in the Synthesis of Hydropentalenes

Synlett ◽  
2020 ◽  
Author(s):  
Sabine Laschat ◽  
Max Deimling ◽  
Anna Zens ◽  
Natja Park ◽  
Christine Hess ◽  
...  
Keyword(s):  
Crown Ether ◽  
Asymmetric Catalysis ◽  
Ring Opening ◽  
Building Blocks ◽  
Biological Properties ◽  
Oxidative Cyclization ◽  
Ring Closing Metathesis ◽  
Ene Reactions ◽  
Cross Metathesis ◽  
Synthetic Approaches

Functionalized hydropentalenes (i.e., bicyclo[3.3.0]octanones) constitute important building blocks for natural products and for ligands for asymmetric catalysis. The assembly and tailored functionalization of this convex roof-shaped scaffold is challenging and has motivated a variety of synthetic approaches including our own contributions, which will be presented in this account.1 Introduction2 Biosynthesis of Hydropentalenes3 Hydropentalenes through the Pauson–Khand Reaction4 Hydropentalenes through Transannular Oxidative Cyclization of Cycloocta-1,4-diene5 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Dodecahydrocyclopenta[a]indenes6 Functionalization of Bicyclo[3.3.0]octan-1,4-diones to Crown Ether Hybrids7 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Cylindramide8 Tandem Ring-Opening Metathesis/Ring-Closing Metathesis/Cross-Metathesis of Bicyclo[2.2.1]heptanes9 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Geodin A10 Hydropentalenes through Enantioselective Desymmetrization of Weiss Diketones11 Functionalization of Weiss Diketones by Carbonyl Ene Reactions12 Functionalization of the Weiss Diketone to Cylindramide and Geodin A Core Units13 Biological Properties of Bicyclo[3.3.0]octanes14 Hydropentalenes through Vinylcyclopropane Cyclopentene Rearrangement15 Functionalization of Bicyclo[3.3.0]octanes toward Chiral Dienes16 Miscellaneous Syntheses of Hydropentalenes17 Conclusion and Outlook

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