scholarly journals Regeneration of Raney®-Nickel Catalyst for the Synthesis of High-Value Amino-Ester Renewable Monomers

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 229
Author(s):  
Ana Soutelo-Maria ◽  
Jean-Luc Dubois ◽  
Jean-Luc Couturier ◽  
Magali Brebion ◽  
Giancarlo Cravotto
Keyword(s):  
Nickel Catalyst ◽  
Catalyst Regeneration ◽  
Amino Ester ◽  
Amino Esters ◽  
Activity Recovery ◽  
Unsaturated Nitrile ◽  
Solvent Wash

Aiming to synthesize high-value renewable monomers for the preparation of renewable specialty polyamides, we designed a new protocol. Amino-esters, produced via the hydrogenation of unsaturated nitrile-esters, are alternative monomers for the production of these polymers. A high monomer yield can be obtained using a Raney®-nickel catalyst despite the drawback of fast deactivation. The hydrogenation of 10-cyano-9-decenoate (UNE11) was tentatively reactivated by three different regeneration procedures: solvent wash, regeneration under hydrogen, and regeneration under sonication. Among these procedures, the in-pot catalyst regeneration (H2 30 bar, 150 °C) demonstrated complete activity recovery and full recycling.

scholarly journals Constrained Dipeptide Surrogates: 5- and 7-Hydroxy Indolizidin-2-one Amino Acid Synthesis from Iodolactonization of Dehydro-2,8-diamino Azelates

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 67
Author(s):  
Ramakotaiah Mulamreddy ◽  
William D. Lubell
Keyword(s):  
Amino Acids ◽  
Acid Synthesis ◽  
Ring System ◽  
Dihedral Angles ◽  
Type Ii ◽  
Amino Ester ◽  
Amino Acid Synthesis ◽  
X Ray ◽  
Amino Esters ◽  
Peptide Mimicry

The constrained dipeptide surrogates 5- and 7-hydroxy indolizidin-2-one N-(Boc)amino acids have been synthesized from L-serine as a chiral educt. A linear precursor ∆4-unsaturated (2S,8S)-2,8-bis[N-(Boc)amino]azelic acid was prepared in five steps from L-serine. Although epoxidation and dihydroxylation pathways gave mixtures of hydroxy indolizidin-2-one diastereomers, iodolactonization of the ∆4-azelate stereoselectively delivered a lactone iodide from which separable (5S)- and (7S)-hydroxy indolizidin-2-one N-(Boc)amino esters were synthesized by sequences featuring intramolecular iodide displacement and lactam formation. X-ray analysis of the (7S)-hydroxy indolizidin-2-one N-(Boc)amino ester indicated that the backbone dihedral angles embedded in the bicyclic ring system resembled those of the central residues of an ideal type II’ β-turn indicating the potential for peptide mimicry.

scholarly journals Optimisation and feature selection of poly-beta-amino-ester as a drug delivery system for cartilage

2020 ◽  
Vol 8 (23) ◽  
pp. 5096-5108 ◽  
Author(s):  
Stefano Perni ◽  
Polina Prokopovich
Keyword(s):  
Drug Delivery ◽  
Feature Selection ◽  
Drug Delivery System ◽  
Delivery System ◽  
Polymer Structure ◽  
Full Potential ◽  
Amino Ester ◽  
Amino Esters ◽  
Drug Conjugates ◽  
Selection Of

Drug localisation is one of the main challenges in treating cartilage; poly-beta-amino-esters (PBAEs) drug conjugates are a possible solution; their efficacy depends on the polymer structure hence the full potential of this system is still unknown.

scholarly journals Stereoselective synthesis of perillaldehyde-based chiral β-amino acid derivatives through conjugate addition of lithium amides

2014 ◽  
Vol 10 ◽  
pp. 2738-2742 ◽  
Author(s):  
Zsolt Szakonyi ◽  
Reijo Sillanpää ◽  
Ferenc Fülöp
Keyword(s):  
Amino Acids ◽  
Stereoselective Synthesis ◽  
Minor Component ◽  
Conjugate Addition ◽  
Building Blocks ◽  
Major Product ◽  
Amino Ester ◽  
Chiral Amine ◽  
Amino Esters ◽  
Lithium Amides

The Michael addition of dibenzylamine to (+)-tert-butyl perillate (3) and to (+)-tert-butyl phellandrate (6), derived from (S)-(−)-perillaldehyde (1), resulted in diastereomeric β-amino esters 7A–D in a moderately stereospecific reaction in a ratio of 76:17:6:1. After separation of the diastereoisomers, the major product, cis isomer 7A, was quantitatively isomerized to the minor component, trans-amino ester 7D. All four isomers were transformed to the corresponding β-amino acids 10A–D, which are promising building blocks for the synthesis of β-peptides and 1,3-heterocycles in three steps. The steric effects of the isopropyl group at position 4 and of the α-methyl substituent of (R)-N-benzyl-N-α-methylbenzylamine on the reactivity were also studied and, upon application of a chiral amine, excellent stereoselectivity of the conjugate addition was observed. Amino ester 11 was obtained as a single product and transformed to the corresponding amino acids 10A and 10D in good yields on the gram scale.

Total synthesis of (–)-pateamine A, a novel immunosuppressive agent from Mycale sp

2004 ◽  
Vol 82 (2) ◽  
pp. 353-365 ◽  
Author(s):  
Gerald Pattenden ◽  
Douglas J Critcher ◽  
Modesto Remuiñán
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Marine Sponge ◽  
Coupling Reaction ◽  
Immunosuppressive Agent ◽  
Side Chain ◽  
Amino Ester ◽  
Stille Reaction ◽  
Amino Esters ◽  
Pateamine A

A convergent synthesis of the unique thiazole-containing polyene bis-lactone pateamine A (1) isolated from the marine sponge Mycale sp is described. The synthesis features the ubiquitous Stille sp2–sp2 coupling reaction to elaborate the E,Z-diene macrolide core 23 and the all-E polyenamine side chain in the natural product. It also highlights the scope for enantiopure sulfinimine intermediates in the synthesis of chiral β-amino ester moieties in complex structures.Key words: pateamine A, immunosuppressive agent from marine sponge Mycale sp, total synthesis, novel 19-membered bis-lactone, thiazole metabolite, polyenamine, Stille reaction, sulfinimines, chiral β-amino esters.

An Alternative Synthesis of Some Carbohydrate α-Amino Acids

2004 ◽  
Vol 57 (1) ◽  
pp. 25 ◽  
Author(s):  
Grant S. Forman ◽  
Adrian Scaffidi ◽  
Robert V. Stick
Keyword(s):  
Amino Acids ◽  
Sodium Azide ◽  
Subsequent Treatment ◽  
Amino Ester ◽  
Alternative Synthesis ◽  
Tertiary Alcohols ◽  
Amino Esters

Several carbohydrate ketones have been converted into their trichloromethyl-branched tertiary alcohols. A subsequent treatment of these alcohols under Corey–Link conditions (base, sodium azide, methanol) has given rise to α-azido esters, transformable into azido acids, amino esters, and amino acids. An amino ester and an azido acid have been coupled to form a dipeptide.

Sign in / Sign up

Export Citation Format

Share Document