Synthesis, Bioassay and NMR Study of Methyleneoxy Isosters of Oxytocin and Vasopressin

2002 ◽  
Vol 67 (3) ◽  
pp. 373-392 ◽  
Author(s):  
Jan Mařík ◽  
Miloš Buděšínský ◽  
Jiřina Slaninová ◽  
Jan Hlaváček
Keyword(s):  
Biological Activities ◽  
Hydrogen Bond Donor ◽  
Total Absence ◽  
Cyclic Hexapeptide ◽  
Stereoselective Hydrogenation ◽  
Backbone Carbonyl ◽  
Nmr Study ◽  
Diastereomeric Mixture ◽  
Hydrolysis Of ◽  
Williamson Reaction

Syntheses of pseudodipeptides H-Tyrψ[CH2O]Ile-OH and H-Tyrψ[CH2O]Phe-OH were carried out using the intramolecular Williamson reaction of O-benzyltyrosinol with ethyl chloroacetate followed by N-protection and aldol reaction of the corresponding morpholin-3-one in position C2 with butanone or benzaldehyde, elimination of the hydroxy group to give derivatives with a double bond either as the E/Z (1 : 1) diastereomeric mixture in the case of the former derivative or as the Z-isomer only in the case of the latter one. Stereoselective hydrogenation and hydrolysis of both the lactams yielded the corresponding pseudodipeptides lacking the carbonyl group as a hydrogen bond donor. The introduction of the pseudodipeptides into positions 2 and 3 of oxytocin and vasopressin caused total absence of all biological activities in the formed analogues. The results of the bioassay and NMR study confirmed the importance of the H-bond between the backbone carbonyl of the Tyr2 and NH proton of the Asn5 residues for stabilization of the β-turn in the cyclic hexapeptide part of both the hormones and for their biological activity.

Synthesis, Characterization and Evaluation of some newer Pyrimidine derivatives as Anti-inflammatory Agents

2021 ◽  
pp. 2529-2534
Author(s):  
Kalpana Divekar ◽  
Rekha. S ◽  
Murugan. Vedigounder ◽  
Shivaprakash. H
Keyword(s):  
Biological Activities ◽  
Diclofenac Sodium ◽  
Pyrimidine Derivative ◽  
Inflammatory Activity ◽  
Paw Edema ◽  
Pyrimidine Derivatives ◽  
Anti Inflammatory ◽  
1Hnmr Spectroscopy ◽  
Hydrolysis Of ◽  
Antiparasitic Agents

Pyrimidine is an important baseone of the base formed by hydrolysis of nucleosides. It is an interesting molecule in the medicinal chemistry because of its diversified biological activities. Alloxan which is an oxidation product of Uric acid is also a pyrimidine derivative of interest to a medicinal chemist. Several pyrimidines are reported as antimicrobial, analegesic, anti-inflammatory, antibacterial, and antiparasitic agents. Pyrimidine scaffold is considered as an interesting one due to its various pharmacological properties. In this scheme, an attempt is made to carry out synthesis of some new pyrimidine derivatives. The Starting material Chalcone is synthesized by condensation of various aromatic aldehyde and aromatic ketone. Chalcone is then treated with thiourea and KOH in presence of ethanol to yield pyrimidine derivatives. Then those pyrimidine derivatives were subjected to alkylation and acetylation. The synthesized compounds were characterized and confirmed by IR and 1HNMR spectroscopy and then evaluated for their anti-inflammatory activity. The anti-inflammatory activity of newly synthesized pyrimidine derivatives were carried out by the carrageenan induced rat hind paw edema method by taking Diclofenac sodium as standard.

NMR study of the synthesis of17O-enriched acetic acid by hydrolysis of acetic anhydride with17O-enriched water

2003 ◽  
Vol 41 (11) ◽  
pp. 959-961 ◽  
Author(s):  
Heidi M. Hultman ◽  
Kristina Djanashvili ◽  
Joop A. Peters
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Nmr Study ◽  
Hydrolysis Of

NMR study of the effect of 5′-AMP on β-lactamase-catalyzed hydrolysis of penicillins

1974 ◽  
Vol 14 (1) ◽  
pp. 52-59
Author(s):  
Frank K Schweighardt ◽  
Jau-Min Guo ◽  
Sze-Ming Yang ◽  
Norman C Li
Keyword(s):  
Nmr Study ◽  
Hydrolysis Of

Hydrolysis of dimethylphenyltin(IV) and triphenyltin(IV) chlorides in different aqueous ethanol solutions

2008 ◽  
Vol 86 (8) ◽  
pp. 751-756 ◽  
Author(s):  
Morteza Jabbari ◽  
Farrokh Gharib ◽  
Mostafa Mohammadpour Amini ◽  
Amirreza Azadmehr
Keyword(s):  
Hydrogen Bond ◽  
Aqueous Ethanol ◽  
Formation Constants ◽  
Single Parameter ◽  
Hydrogen Bond Donor ◽  
Hydrogen Bond Acceptor ◽  
Polarity Parameter ◽  
Wide Ph Range ◽  
Hydrogen Bond Acceptor Basicity ◽  
Hydrolysis Of

The hydrolysis of [(Me)2(Ph)Sn(IV)]+ and [(Ph)3Sn(IV)]+ has been investigated at 25 °C and different aqueous solutions of ethanol, using a combination of spectrophotometric and potentiometric techniques. The species formed together with their formation constants have been determined using the computer program Squad over a wide pH range of 1 to 11. The hydrolysis constants in different media were analyzed in terms of Kamlet and Taft parameters. Single-parameter correlation of the formation constants, K11 and K12, versus α (hydrogen-bond donor acidity), β (hydrogen-bond acceptor basicity), and π* (dipolarity/polarizability) for both cases are relatively poor in all solutions, but multiparameter correlation represents significant improvement with regard to the single-parameter models. In this work, we have also used the normalized polarity parameter, ETN, alone and in combination with the Kamlet–Taft parameter to find a better correlation of the formation constants in different aqueous ethanol solutions.Key words: dimethylphenyltin(IV) chloride, triphenyltin(IV) chloride, hydrolysis constant, aqueous ethanol solutions, solvent effect.

scholarly journals Organic Acid-Catalyzed Subcritical Water Hydrolysis of Immature Citrus unshiu Pomace

Foods ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Sang-Bin Lim
Keyword(s):  
Citric Acid ◽  
Organic Acid ◽  
Acid Concentration ◽  
Subcritical Water ◽  
Biological Activities ◽  
Citrus Unshiu ◽  
Citric Acid Concentration ◽  
Acid Catalyzed ◽  
Inhibitory Activities ◽  
Hydrolysis Of

Immature Citrus unshiu pomace (ICUP) was hydrolyzed under organic acid-catalyzed, subcritical water (SW) conditions to produce flavonoid monoglucosides (hesperetin-7-O-glycoside and prunin) and aglycons (hesperetin and naringenin) with high biological activities. The results of single-factor experiments showed that with 8 h of hydrolysis and an increasing citric acid concentration, the yield of flavonoid monoglucosides (hesperetin-7-O-glycoside and prunin) increased from 0 to 7% citric acid. Afterward, the hesperetin-7-O-glycoside yield remained constant (from 7 to 19% citric acid) while the pruning yield decreased with 19% of citric acid, whereas the aglycon yield increased continuously. In response surface methodology analysis, a citric acid concentration and hydrolysis duration of 13.34% and 7.94 h were predicted to produce the highest monoglucoside yield of 15.41 mg/g, while 18.48% citric acid and a 9.65 h hydrolysis duration produced the highest aglycon yield of 10.00 mg/g. The inhibitory activities of the SW hydrolysates against pancreatic lipase (PL) and xanthine oxidase (XO) were greatly affected by citric acid concentration and hydrolysis duration, respectively. PL and α-glucosidase inhibition rates of 88.2% and 62.7%, respectively, were achieved with 18.48% citric acid and an 8 h hydrolysis duration, compared to 72.8% for XO with 16% citric acid and 12 h of hydrolysis. This study confirms the potential of citric acid-catalyzed SW hydrolysis of ICUP for producing flavonoid monoglucosides and aglycons with enhanced enzyme inhibitory activities.

scholarly journals Kinetic Separation of cis-and trans-Limonene Epoxide: Reaction of Diastereomeric Mixture of Limonene Oxides with Secondary Amine and Carbamate

2021 ◽  
Vol 33 (11) ◽  
pp. 2667-2670
Author(s):  
M.M. El Hammoumi ◽  
L. Ait Said ◽  
A. El Bachiri ◽  
M. Khoukhi
Keyword(s):  
Trans Isomer ◽  
Secondary Amine ◽  
Ethyl Carbamate ◽  
Epoxide Ring ◽  
Diastereomeric Mixture ◽  
Limonene Oxide ◽  
Cis And Trans ◽  
Hydrolysis Of ◽  
Diastereomeric Purity ◽  
Kinetic Separation

A simple kinetic separation of (1:1) diastereomeric mixture of limonene oxides was used to purify cis-and trans-diastereomers of (R)-(+)-limonene oxide. The epoxide ring of trans-isomer was selectively opened by (R)-N-methyl-(α-methyl-benzyl)amine. This secondary nucleophilic amine left cis-limonene oxide largely unreacted and was obtained up to 90% yield. In a diverse way, (R)-N-(α-methylbenzyl) ethyl carbamate, selectively catalyze hydrolysis of cis-limonene oxide to 1,2-limonene diol leaving trans-limonene oxide largely unreacted. The unreacted trans-limonene oxide was recovered in up to 75% yield. HPLC and NMR analyses were used to demonstrate that the isolation of cis-and trans-diastereomers of (R)-(+)-limonene oxide has shown that > 98% were pure. As a result, depending on the realization of the secondary amine or carbamate in the presence of water, either cis-or trans-limonene oxide may be obtained in high diastereomeric purity.

A Panoramic Review of Benzimidazole Derivatives and Their Potential Biological Activity

2022 ◽  
Vol 22 ◽  
Author(s):  
Hiram Hernández-López ◽  
Christian Jairo Tejada-Rodríguez ◽  
Socorro Leyva-Ramos
Keyword(s):  
Biological Activity ◽  
Hydrophobic Interactions ◽  
Therapeutic Potential ◽  
Biological Activities ◽  
Benzimidazole Derivatives ◽  
Drug Candidate ◽  
Hydrogen Bond Donor ◽  
Wide Range ◽  
Donor Acceptor ◽  
Potent Drug

Abstract: The therapeutic potential of the benzimidazole nucleus dates back to 1944, being and important heterocycle system due to its presence in a wide range of bioactive compounds such as antiviral, anticancer, antibacterial, and so on, where optimization of substituents in this class of pharmacophore has resulted in many drugs. Its extensive biological activity is due to its physicochemical properties like hydrogen bond donor-acceptor capability,  stacking interactions, coordination bonds with metals as ligands and hydrophobic interactions; properties that allow them to easily bind with a series of biomolecules, including enzymes and nucleic acids, causing a growing interest in these types of molecules. This review aims to present an overview to leading benzimidazole derivatives, as well as to show the importance of the nature and type of substituents at the N1, C2, and C5(6) positions, when they are biologically evaluated, which can lead to obtaining potent drug candidate with significant range of biological activities.

Cationic Reverse Micelles Create Water with Super Hydrogen-Bond-Donor Capacity for Enzymatic Catalysis: Hydrolysis of 2-Naphthyl Acetate by α-Chymotrypsin

2010 ◽  
Vol 16 (29) ◽  
pp. 8887-8893 ◽  
Author(s):  
Fernando Moyano ◽  
R. Dario Falcone ◽  
J. C. Mejuto ◽  
Juana J. Silber ◽  
N. Mariano Correa
Keyword(s):  
Hydrogen Bond ◽  
Reverse Micelles ◽  
Enzymatic Catalysis ◽  
Hydrogen Bond Donor ◽  
Donor Capacity ◽  
Hydrolysis Of ◽  
Naphthyl Acetate
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