A Strategy of In Situ Catalysis and Nucleation of Biocompatible Zinc Salts of Amino Acids towards Poly(l-lactide) with Enhanced Crystallization Rate

The intrinsic drawback of slow crystallization rate of poly(l-lactide) (PLLA) inevitably deteriorates its final properties of the molded articles. In this work, we proposed a new strategy towards poly(l-lactide) with enhanced crystallization rate by ring opening polymerization (ROP) of l-lactide (l-LA) catalyzed by biocompatible zinc salts of amino acids. For the first time we developed a one-pot facile method of zinc salts of amino acids acting dual roles of catalysis of l-LA polymerization and in situ nucleation of the as-prepared PLLA. Nine zinc salts of different amino acids, including three kinds of amino acids ligands (alanine, phenylalanine, and proline) with l/d-enantiomers and their equimolar racemic mixtures, were first prepared and tested as catalysts of l-LA polymerization. A partial racemization was observed for zinc salts of amino acids whereas no racemization was detected for the reference stannous octoate. The polymerization mechanism study showed that the interaction of zinc salts of amino acids and benzyl alcohol forms the actual initiator for l-LA polymerization. Isothermal crystallization kinetics analysis showed that the residual zinc salts of amino acids exhibited a significant nucleation effect on PLLA, evidenced by the promotion of the crystallization rate, depending on the amino acid ligand and its configuration. Meanwhile, the residual zinc salts of amino acids did not compromise the thermal stability of the pristine PLLA.

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A facile one pot route for the synthesis of imide tethered peptidomimetics

Organic & Biomolecular Chemistry ◽

10.1039/c5ob01708d ◽

2016 ◽

Vol 14 (2) ◽

pp. 556-563 ◽

Cited By ~ 6

Author(s):

Veladi Panduranga ◽

Girish Prabhu ◽

Roopesh Kumar ◽

Basavaprabhu Basavaprabhu ◽

Vommina V. Sureshbabu

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Efficient Method ◽

One Pot ◽

Protected Amino Acid

A simple and efficient method for the synthesis of N,N’-orthogonally protected imide tethered peptidomimetics is presented. The imide peptidomimetics were synthesized by coupling the in situ generated selenocarboxylate of Nα-protected amino acids with Nα-protected amino acid azides in good yields.

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One-pot synthesis of enantiomerically pure N-protected allylic amines from N-protected α-amino esters

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.12.94 ◽

2016 ◽

Vol 12 ◽

pp. 957-962 ◽

Cited By ~ 1

Author(s):

Gastón Silveira-Dorta ◽

Sergio J Álvarez-Méndez ◽

Víctor S Martín ◽

José M Padrón

Keyword(s):

Amino Acids ◽

Allylic Amines ◽

One Pot ◽

Enantiomerically Pure ◽

Amino Esters ◽

One Pot Synthesis ◽

Sequential Reduction ◽

Natural Amino Acids ◽

Hydroxy Groups

An improved protocol for the synthesis of enantiomerically pure allylic amines is reported. N-Protected α-amino esters derived from natural amino acids were submitted to a one-pot tandem reduction–olefination process. The sequential reduction with DIBAL-H at −78 °C and subsequent in situ addition of organophosphorus reagents yielded the corresponding allylic amines without the need to isolate the intermediate aldehyde. This circumvents the problem of instability of the aldehydes. The method tolerates well both Wittig and Horner–Wadsworth–Emmons organophosphorus reagents. A better Z-(dia)stereoselectivity was observed when compared to the previous one-pot method. The (dia)stereoselectivity of the process was affected neither by the reaction solvent nor by the amount of DIBAL-H employed. The method is compatible with the presence of free hydroxy groups as shown with serine and threonine derivatives.

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Multicomponent synthesis of spiropyrrolidine analogues derived from vinylindole/indazole by a 1,3-dipolar cycloaddition reaction

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.12.288 ◽

2016 ◽

Vol 12 ◽

pp. 2893-2897 ◽

Cited By ~ 5

Author(s):

Manjunatha Narayanarao ◽

Lokesh Koodlur ◽

Vijayakumar G Revanasiddappa ◽

Subramanya Gopal ◽

Susmita Kamila

Keyword(s):

Amino Acids ◽

Cycloaddition Reaction ◽

Thermal Conditions ◽

Azomethine Ylides ◽

Dipolar Cycloaddition ◽

Side Chains ◽

Multicomponent Synthesis ◽

One Pot ◽

Cyclic Adducts

A new series of spiropyrrolidine compounds containing indole/indazole moieties as side chains have been accomplished via a one-pot multicomponent synthesis. The method uses the 1,3-dipolar cycloaddition reaction between N-alkylvinylindole/indazole and azomethine ylides, prepared in situ from cyclic/acyclic amino acids. The 1,3-dipolar cycloaddition proceeds efficiently under thermal conditions to afford the regio- and stereospecific cyclic adducts.

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Assemblies of D-peptides for Targeting Cell Nucleolus

10.26434/chemrxiv.8247179.v1 ◽

2019 ◽

Author(s):

Huaimin Wang ◽

Zhaoqianqi Feng ◽

Weiyi Tan ◽

Bing Xu

Keyword(s):

Particle Morphology ◽

Side Chain ◽

Mechanism Study ◽

Structural Analogue ◽

Hydrophobic Residues ◽

Subcellular Organelles ◽

First Case ◽

New Strategy ◽

Peptide Derivative ◽

Peptide Nanoparticles

<p>Selectively targeting cell nucleolus remains a challenge. Here we report the first case that D-peptides form membraneless molecular condensates with RNA for targeting cell nucleolus. A D-peptide derivative, enriched with lysine and hydrophobic residues, self-assembles to form nanoparticles, which enter cells through clathrin dependent endocytosis and mainly accumulate at cell nucleolus. Structural analogue of the D-peptide reveals that particle morphology of the assemblies, which depends on the side chain modification, favors the cellular uptake. Contrasting to those of the D-peptide, the assemblies of the corresponding L-enantiomer largely localize in cell lysosomes. Preliminary mechanism study suggests that the D-peptide nanoparticles interact with RNA to form membraneless condensates in the nucleolus, which further induces DNA damage and results in cell death. This work illustrates a new strategy for rationally designing supramolecular assemblies of D-peptides for targeting subcellular organelles.</p>

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In-Situ Liquid Phase Catalytic Hydrogenation for One-Pot Synthesis of Quino-lines from Aromatic Nitro Compounds

CHINESE JOURNAL OF CATALYSIS (CHINESE VERSION) ◽

10.3724/sp.j.1088.2012.20341 ◽

2013 ◽

Vol 33 (8) ◽

pp. 1423-1426

Author(s):

Huizi GU ◽

Xiangsheng XU ◽

Ao’ang CHEN ◽

Xinhuan YAN

Keyword(s):

Liquid Phase ◽

Catalytic Hydrogenation ◽

Nitro Compounds ◽

One Pot ◽

Aromatic Nitro Compounds ◽

One Pot Synthesis ◽

Aromatic Nitro

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Indium Bromide-catalyzed Unprecedented Hydrogenolysis: A Novel One-Pot Synthesis of Per-O-Acetylated β-carboxymethyl O and S-glycosides

Current Organic Chemistry ◽

10.2174/1385272824999200407093625 ◽

2020 ◽

Vol 24 (8) ◽

pp. 900-908

Author(s):

Ram Naresh Yadav ◽

Amrendra K Singh ◽

Bimal Banik

Keyword(s):

Asymmetric Synthesis ◽

Chiral Auxiliary ◽

Bioactive Molecules ◽

One Pot ◽

Enantiomerically Pure ◽

Stereoselective Glycosylation ◽

One Pot Synthesis ◽

Wide Range

Numerous O (oxa)- and S (thia)-glycosyl esters and their analogous glycosyl acids have been accomplished through stereoselective glycosylation of various peracetylated bromo sugar with benzyl glycolate using InBr3 as a glycosyl promotor followed by in situ hydrogenolysis of resulting glycosyl ester. A tandem glycosylating and hydrogenolytic activity of InBr3 has been successfully investigated in a one-pot procedure. The resulting synthetically valuable and virtually unexplored class of β-CMGL (glycosyl acids) could serve as an excellent potential chiral auxiliary in the asymmetric synthesis of a wide range of enantiomerically pure medicinally prevalent β-lactams and other bioactive molecules of diverse medicinal interest.

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Synthesis of Unnatural Amino Acids via Microwave-assisted Regio-selective One-pot multi-component Reactions of Sulfamidates

Current Organic Chemistry ◽

10.2174/13852728113179990047 ◽

2013 ◽

Vol 17 (20) ◽

pp. 2323-2331 ◽

Cited By ~ 4

Author(s):

Nasir Baig ◽

Rajender Varma

Keyword(s):

Amino Acids ◽

Unnatural Amino Acids ◽

One Pot ◽

Microwave Assisted

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A Facile One-pot Synthesis of Substituted Quinolines via Cascade Friedlander Reaction from Isoxazoles with Ammonium Formate-Pd/C and Ketones

Letters in Organic Chemistry ◽

10.2174/1570178616666190618091617 ◽

2020 ◽

Vol 17 (3) ◽

pp. 211-215

Author(s):

Da Chen ◽

Xuan Wang ◽

Runnan Wang ◽

Yao Zhan ◽

Xiaohan Peng ◽

...

Keyword(s):

Hydrogen Transfer ◽

Ammonium Formate ◽

Aromatic Ketone ◽

Reaction Conditions ◽

One Pot ◽

Diverse Range ◽

Strong Base ◽

Aromatic Ketones ◽

Substituted Quinolines ◽

New Strategy

The Friedlander reaction is the most commonly used method to synthesis substituted quinolines, the essential intermediates in the medicine industry. A facile one-pot approach for synthesizing substituted quinolines by the reaction of isoxazoles, ammonium formate-Pd/C, concentrated sulfuric acid, methanol and ketones using Friedlander reaction conditions is reported. Procedures for the synthesis of quinoline derivatives were optimized, and the yield was up to 90.4%. The yield of aromatic ketones bearing electron-withdrawing groups was better than the ones with electron-donating substituents. The structures of eight substituted quinolines were characterized by MS, IR, H-NMR and 13CNMR, which were in agreement with the expected structures. The mechanism for the conversion was proposed, which involved the Pd/C catalytic hydrogen transfer reduction of unsaturated five-membered ring of isoxazole to produce ortho-amino aromatic ketones. Then the nucleophilic addition of with carbonyl of the ketones generated Schiff base in situ, which underwent an intermolecular aldol reaction followed by the elimination of H2O to give production of substituted quinolines. This new strategy can be readily applied for the construction of quinolines utilizing a diverse range of ketones and avoids the post-reaction separation of the o-amino aromatic ketone compounds. The conventionally used o-amino aromatic ketone compounds in Friedlander reaction to prepare substituted quinoline are laborious to synthesize and are apt to self-polymerize. While oxazole adopted in this work can be prepared at ease by the condensation of benzoacetonitrile and nitrobenzene derivatives under the catalysis of a strong base. Moreover, the key features of this protocol are readily available starting materials, excellent functional group tolerance, mild reaction conditions, operational simplicity, and feasibility for scaling up.

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