Radiolytic Oxidation of Peptide Derivatives of Glycine in Aqueous Solution

The synthesis of Boc-Gly-Pro-Dox, Boc-Gly-Pro-DOPA, Boc-Gly-Pro-Srt and their deuterated analogs was carried out. It was shown that these condensations proceed with side reactions, which could be minimized by optimizing the conditions for the synthesis. The most universal approach to the synthesis of Boc-Gly-Pro-Dox, Boc-Gly-Pro-DOPA, Boc-Gly-Pro-Srt and their deuterated analogs is condensation of Boc-Gly-Pro or Boc-Gly-[2H]Pro with amino groups of dopamine, serotonin and doxorubicin. It was found that for the introduction of hydrogen isotopes in ΔPro, it is advisable to hydrogenate its aqueous solution, followed by condensation of the reduced proline with Boc-GlyOSu. Mass spectrometry was used to determine the content of isotopomers in deuterated products.

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Synthesis of New Peptide Derivatives of Galanthamine Designed for Prevention and Treatment of Alzheimer’s Disease

Protein and Peptide Letters ◽

10.2174/0929866522666150701111642 ◽

2015 ◽

Vol 22 (10) ◽

pp. 913-922 ◽

Cited By ~ 2

Author(s):

Lyubomir Vezenkov ◽

Lilia Ilieva ◽

Dancho Danalev ◽

Anastasia Bakalova ◽

D. Vassilev ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Prevention And Treatment ◽

Peptide Derivatives ◽

Derivatives Of

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Quantum-Chemical Search for Keto Tautomers of Azulenols in Vacuo and Aqueous Solution

Symmetry ◽

10.3390/sym13030497 ◽

2021 ◽

Vol 13 (3) ◽

pp. 497

Author(s):

Ewa D. Raczyńska

Keyword(s):

Aqueous Solution ◽

Quantum Chemical ◽

Biologically Active ◽

Deprotonation Reaction ◽

Chemical Studies ◽

Quantum Chemical Studies ◽

Scanty Information ◽

Derivatives Of ◽

Common Anion ◽

Tautomeric Mixture

Keto-enol prototropic conversions for carbonyl compounds and phenols have been extensively studied, and many interesting review articles and even books appeared in the last 50 years. Quite a different situation takes place for derivatives of biologically active azulene, for which only scanty information on this phenomenon can be found in the literature. In this work, quantum-chemical studies have been undertaken for symmetrically and unsymmetrically substituted azulenols (constitutional isomers of naphthols). Stabilities of two enol (OH) rotamers and all possible keto (CH) tautomers have been analyzed in the gas phase {DFT(B3LYP)/6-311+G(d,p)} and also in aqueous solution {PCM(water)//DFT(B3LYP)/6-311+G(d,p)}. Contrary to naphthols, for which the keto forms can be neglected, at least one keto isomer (C1H, C2H, and/or C3H) contributes significantly to the tautomeric mixture of each azulenol to a higher degree in vacuo (non-polar environment) than in water (polar amphoteric solvent). The highest amounts of the CH forms have been found for 2- and 5-hydroxyazulenes, and the smallest ones for 1- and 6-hydroxy derivatives. The keto tautomer(s), together with the enol rotamers, can also participate in deprotonation reaction leading to a common anion and influence its acid-base properties. The strongest acidity in vacuo exhibits 6-hydroxyazulene, and the weakest one displays 1-hydroxyazulene, but all azulenols are stronger acids than phenol and naphthols. Bond length alternation in all DFT-optimized structures has been measured using the harmonic oscillator model of electron delocalization (HOMED) index. Generally, the HOMED values decrease for the keto tautomers, particularly for the ring containing the labile proton. Even for the keto tautomers possessing energetic parameters close to those of the enol isomers, the HOMED indices are low. However, some kind of parallelism exists for the keto forms between their relative energies and HOMEDs estimated for the entire molecules.

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Thiol-based inhibitors of mammalian collagenase. Substituted amide and peptide derivatives of the leucine analogue, 2-[(R,S)-mercaptomethyl]-4-methylpentanoic acid.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)34106-7 ◽

1990 ◽

Vol 265 (9) ◽

pp. 5199-5205

Author(s):

K Darlak ◽

R B Miller ◽

M S Stack ◽

A F Spatola ◽

R D Gray

Keyword(s):

Peptide Derivatives ◽

Derivatives Of

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SYNTHESIS AND ANTIMICROBIAL EVALUATION OF QUINAZOLINONE PEPTIDE DERIVATIVES

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2017.v10s4.21329 ◽

2017 ◽

Vol 10 (16) ◽

pp. 7 ◽

Cited By ~ 2

Author(s):

Bhupinder Kapoor ◽

Arshid Nabi ◽

Reena Gupta ◽

Mukta Gupta

Keyword(s):

Antibacterial Activity ◽

Amino Acid ◽

Antimicrobial Agents ◽

Methyl Esters ◽

Standard Drug ◽

Amino Acid Peptide ◽

Chemical Structures ◽

1H Nuclear Magnetic Resonance ◽

Peptide Derivatives ◽

Derivatives Of

Objective: The increased microbial resistance against commercially available drugs initiated the development of novel and safe antimicrobial agents in last few decades. In this view, a series of amino acid/dipeptide derivatives of quinazolin-3(4H)-one was synthesized and was evaluated for their antimicrobial potential.Method: Synthesis of amino acid/peptide derivatives were carried out by coupling 5-(2-(2-chlorophenyl)-4-oxoquinazolin-3(4H)-yl)-2-hydroxy benzoic acid with amino acid/dipeptide methyl esters in the presence of dicyclohexylcarbodiimide and N-methylmorpholine. The chemical structures of synthesized compounds were characterized by 1H nuclear magnetic resonance and infrared spectroscopy and were screened for antibacterial activity by disc diffusion method.Results: All the synthesized derivatives exhibited moderate to significant antibacterial activity against both Gram-positive and Gram-negative bacteria. The potency of compound 5d was comparable to standard drug ciprofloxacin in all the strains of bacteria used. The compound 5a was found to be more active against Streptococcus pyogenes and Staphylococcus aureus while compound 5c against Pseudomonas aeruginosa and Escherichia coli. Conclusion: Peptide derivatives of quinazolinone are promising antimicrobial agent and can be used for the synthesis of other novel compounds.

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