scholarly journals Amino acid-derived bisphenolate palladium complexes as C-C coupling catalysts

2021 ◽  
Author(s):  
Eszter Fazekas ◽  
David T Jenkins ◽  
Andrew A Forbes ◽  
Brendan Gallagher ◽  
Georgina Rosair ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Ester ◽  
Amino Acid Ester ◽  
Palladium Complexes ◽  
Synthetic Method ◽  
Naturally Occurring ◽  
Chiral Amino Acids ◽  
Pendant Arms

A series of amine bisphenol (ABP) pro-ligands featuring amino acid ester pendant arms were prepared. Optimisation of the synthetic method allowed the facile incorporation of naturally occurring, chiral amino acids...

scholarly journals Transdermal Delivery Systems for Ibuprofen and Ibuprofen Modified with Amino Acids Alkyl Esters Based on Bacterial Cellulose

2021 ◽  
Vol 22 (12) ◽  
pp. 6252
Author(s):  
Paula Ossowicz-Rupniewska ◽  
Rafał Rakoczy ◽  
Anna Nowak ◽  
Maciej Konopacki ◽  
Joanna Klebeko ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Bacterial Cellulose ◽  
Acid Ester ◽  
Active Pharmaceutical Ingredient ◽  
Amino Acid Ester ◽  
Isopropyl Ester ◽  
Isopropyl Esters ◽  
Transdermal Application

The potential of bacterial cellulose as a carrier for the transport of ibuprofen (a typical example of non-steroidal anti-inflammatory drugs) through the skin was investigated. Ibuprofen and its amino acid ester salts-loaded BC membranes were prepared through a simple methodology and characterized in terms of structure and morphology. Two salts of amino acid isopropyl esters were used in the research, namely L-valine isopropyl ester ibuprofenate ([ValOiPr][IBU]) and L-leucine isopropyl ester ibuprofenate ([LeuOiPr][IBU]). [LeuOiPr][IBU] is a new compound; therefore, it has been fully characterized and its identity confirmed. For all membranes obtained the surface morphology, tensile mechanical properties, active compound dissolution assays, and permeation and skin accumulation studies of API (active pharmaceutical ingredient) were determined. The obtained membranes were very homogeneous. In vitro diffusion studies with Franz cells were conducted using pig epidermal membranes, and showed that the incorporation of ibuprofen in BC membranes provided lower permeation rates to those obtained with amino acids ester salts of ibuprofen. This release profile together with the ease of application and the simple preparation and assembly of the drug-loaded membranes indicates the enormous potentialities of using BC membranes for transdermal application of ibuprofen in the form of amino acid ester salts.

A convenient preparative method for esters of amino acids

1972 ◽  
Vol 25 (6) ◽  
pp. 1293 ◽  
Author(s):  
JA Maclaren
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Ester ◽  
Preparative Method ◽  
Amino Acid Ester ◽  
Carboxyl Group ◽  
Amino Groups ◽  
Amino Protection

The amino groups of amino acids can be protected by using ethyl ecetoacetate as a ,β-dicarbonyl component. The resulting derivatives are readily alkylated at the carboxyl group by substituted benzyl and other halides. Mild acidolysis then removes the amino protection to give the salt of the amino acid ester. This three-step synthesis can be performed without isolation of intermediates and provides a convenient preparative method for 4-methoxybenzyl, 2,4,6-trimethyl-benzyl, 4-nitrobenzyl, and 4-picolyl esters of amino acids. The products are not racemized.

scholarly journals An Amino Acid Ester of Menthol Elicits Defense Responses in Plants

2021 ◽  
Author(s):  
Chisato Tsuzuki ◽  
Masakazu Hachisu ◽  
Rihoko Iwabe ◽  
Yuna Nakayama ◽  
Yoko Nonaga ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plant Defense ◽  
Pest Control ◽  
Acid Ester ◽  
Transcript Level ◽  
Defense Responses ◽  
Amino Acid Ester ◽  
Defense Genes ◽  
Soybean Plants

Abstract Terpenoids, including menthol, exhibit potent abilities as plant defense potentiators in agriculture and horticulture. In the current study, we developed new terpene derivatives that consisted of menthol and various amino acids and that were expected to act as powerful plant defense potentiators. We used 6 amino acids possessing low-reactive sidechains to synthesize an array of amino acid ester of menthol (ment-aa) compounds. Transcript levels of two defense genes (pathogenesis-related 1 [PR1] and trypsin inhibitor [TI]) were evaluated in leaves of soybean plants 24 h after application of aquatic solution of menthol or menthol-aa, and revealed that the menthol menthyl ester of valine (ment-Val) alone elevated the transcript level of defense genes, and it did so only at the low dose of 1 µM, not at higher or lower doses tested. Moreover, it appeared that histone acetylation was involved in this effect. Application of ment-Val enabled soybean plants to sustain the increased transcript levels in their leaves for up to 3 days. Moreover, when ment-Val was additionally applied at day 4, at which time the transcript level had declined to the basal level, the transcript level was re-elevated, indicating the possibility that ment-Val could be repeatedly used to sustain pest control. Ment-Val was found to be chemically stable and effective for defense of several crop species. Collectively, these data show that terpenoid conjugates are useful for pest control instead of or in addition to pesticides.

Biomimetic Membrane Transport: Interesting Ionophore Functions of Naturally Occurring Polyether Antibiotics toward Unusual Metal Cations and Amino Acid Ester Salts

1994 ◽  
Vol 33 (13) ◽  
pp. 2984-2987 ◽  
Author(s):  
Hiroshi Tsukube ◽  
Kentaro Takagi ◽  
Tatsuo Higashiyama ◽  
Tadashi Iwachido ◽  
Naomi Hayama
Keyword(s):  
Amino Acid ◽  
Membrane Transport ◽  
Acid Ester ◽  
Metal Cations ◽  
Amino Acid Ester ◽  
Naturally Occurring ◽  
Biomimetic Membrane

scholarly journals SYNTHESIS AND EVALUATION OF AMINO ACID ESTER CONJUGATES OF HIV PROTEASE INHIBITOR

2019 ◽  
pp. 342-346
Author(s):  
CHABUKSWAR AR Mehta ◽  
PREETI M. GANDHI
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protease Inhibitor ◽  
Acid Ester ◽  
Oral Absorption ◽  
Therapeutic Potential ◽  
Hydrolytic Stability ◽  
Amino Acid Ester ◽  
Hiv Protease ◽  
Hiv Protease Inhibitor

Objective: Ester conjugates of HIV protease inhibitor, lopinavir (LP) with various amino acids were synthesized to improve its physicochemical and pharmacokinetic profile and consequently therapeutic potential. Materials and Methods: Conjugates of LP with amino acids; glycine, alanine, valine, and serine were prepared by dicyclohexylcarbodiimide coupling method. The synthesized compounds were characterized by nuclear magnetic resonance, mass, and Fourier-transform infrared spectroscopy and evaluated for their solubility, partition coefficient, hydrolytic stability, cytotoxicity, and permeability through Caco-2 cells. Results: Aqueous solubility studies indicated significantly better solubility profiles of all conjugates as compared to LP. With respect to hydrolysis, all the conjugates displayed higher stability under acidic conditions while undergo hydrolysis with rise in pH. Conjugates did not exhibit cytotoxicity for concentration as high as 100 μg/ml, which indicates promising therapeutic potential. Absorptive diffusion of drug across Caco-2 cell monolayers was improved by amino acid conjugation. Conclusion: Amino acid ester conjugates of LP not only showed better solubility but also significantly higher permeability than LP. Thus, direct conjugation of L-amino acids is a viable approach to improve oral absorption and thereby oral bioavailability of protease inhibitors.

Eco-Friendly Synthesis of Peptides Using Fmoc-Amino Acid Chlorides as Coupling Agent Under Biphasic Condition

2020 ◽  
Vol 27 ◽  
Author(s):  
Santosh Y. Khatavi ◽  
K. Kantharaju
Keyword(s):  
Amino Acid ◽  
Acid Chloride ◽  
Acid Ester ◽  
Analytical Techniques ◽  
Peptide Bond ◽  
Amino Acid Ester ◽  
Acid Chlorides ◽  
Peptide Bond Formation ◽  
Green Protocol ◽  
Additional Base

Background: Agro-waste derived solvent media act as a greener process for the peptide bond formation using Nα - Fmoc-amino acid chloride and amino acid ester salt with in situ neutralization and coupling under biphasic condition. The Fmoc-amino acid chlorides are prepared by the reported procedure of freshly distilled SOCl2 with dry CH2Cl2. The protocol found many added advantages such as neutralization of amino acid ester salt and not required additional base for the neutralization, and directly coupling take place with Fmoc-amino acid chloride gave final product dipeptide ester in good to excellent yields. The protocol occurs with complete stereo chemical integrity of the configuration of substrates. Here, we revisited Schotten-Baumann condition, instead of using inorganic base. Objective: To develop green protocol for the synthesis of peptide bond using Fmoc-amino acid chloride with amino acid esters salt. Methods: The final product isolated is analyzed in several spectroscopic and analytical techniques such as FT-IR, 1H-, 13CNMR, Mass spectrometry and RP-HPLC to check stereo integrity and purity of the product. Conclusion: The present method developed greener using natural agro-waste (lemon fruit shell ash) derived solvent medium for the reaction and not required chemical entity.

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