scholarly journals Substrate switchable Suzuki–Miyaura coupling for benzyl ester vs. benzyl halide

RSC Advances ◽  
2018 ◽  
Vol 8 (61) ◽  
pp. 35056-35061 ◽  
Author(s):  
Masato Ohsumi ◽  
Akitaka Ito ◽  
Nagatoshi Nishiwaki
Keyword(s):  
Benzyl Ester ◽  
Reaction Conditions ◽  
Benzyl Halide ◽  
Benzyl Halides ◽  
Benzyl Esters

Two reaction conditions were developed to accomplish the substrate switchable (benzyl esters vs. benzyl halides) Suzuki–Miyaura coupling.

Comparative effects of L-NNA and alkyl esters of L-NNA on pulmonary vasodilator responses to ACh, BK, and SP

1994 ◽  
Vol 266 (6) ◽  
pp. H2416-H2422 ◽  
Author(s):  
D. Y. Cheng ◽  
B. J. DeWitt ◽  
T. J. McMahon ◽  
P. J. Kadowitz
Keyword(s):  
Substance P ◽  
Vagal Stimulation ◽  
Benzyl Ester ◽  
No Synthase ◽  
Flow Conditions ◽  
Inhibitory Effects ◽  
Vascular Bed ◽  
Pulmonary Vasodilator ◽  
Benzyl Esters ◽  
Pulmonary Vascular Bed

The comparative effects of the nitric oxide (NO) synthase inhibitors N omega-nitro-L-arginine (L-NNA), N omega-nitro-L-arginine methyl ester (L-NAME), and N omega-nitro-L-arginine benzyl ester (L-NABE) on baseline tone and on vasodilator responses to acetylcholine (ACh), bradykinin (BK), and substance P (SP) were compared in the pulmonary vascular bed of the cat under constant flow conditions. After administration of the NO synthase inhibitors in intravenous doses of 100 mg/kg, the increase in lobar arterial pressure and the attenuation of vasodilator responses to ACh, BK, and SP were similar, whereas responses to adenosine and felodipine, endothelium-independent vasodilator agents, were not altered. In addition to inhibiting responses to ACh, BK, and substance P, the NO synthase inhibitors enhanced vasodilator responses to S-nitroso-N-acetylpenicillamine and NO. Moreover, atropine inhibited pulmonary vasodilator responses to ACh but not to SP or BK, and L-NAME or L-NABE had no effect on the decrease in heart rate in response to efferent vagal stimulation, a muscarinic receptor-mediated response that is independent of NO release. The similar inhibitory effects of L-NNA, L-NAME, and L-NABE on vasodilator responses to ACh, BK, and SP suggest that the L-arginine analogue, L-NNA, as well as the methyl and benzyl esters of L-NNA are useful probes for studying NO-mediated endothelium-dependent responses in the pulmonary vascular bed of the intact-chest cat.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Design, Synthesis and Biological Evaluation of Pentacyclic Triterpene Derivatives: Optimization of Anti-ABL Kinase Activity

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3535 ◽  
Author(s):  
Halil I. Ciftci ◽  
Mohamed O. Radwan ◽  
Safiye E. Ozturk ◽  
N. Gokce Ulusoy ◽  
Ece Sozer ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
K562 Cells ◽  
Biological Evaluation ◽  
Benzyl Ester ◽  
Myelogenous Leukemia ◽  
Pentacyclic Triterpene ◽  
Abl Kinase ◽  
Molecular Targeted Drug ◽  
Benzyl Esters

Imatinib, an Abelson (ABL) tyrosine kinase inhibitor, is a lead molecular-targeted drug against chronic myelogenous leukemia (CML). To overcome its resistance and adverse effects, new inhibitors of ABL kinase are needed. Our previous study showed that the benzyl ester of gypsogenin (1c), a pentacyclic triterpene, has anti-ABL kinase and a subsequent anti-CML activity. To optimize its activities, benzyl esters of carefully selected triterpenes (PT1–PT6), from different classes comprising oleanane, ursane and lupane, and new substituted benzyl esters of gypsogenin (GP1–GP5) were synthesized. All of the synthesized compounds were purified and charachterized by different spectroscopic methods. Cytotoxicity of the parent triterpenes and the synthesized compounds against CML cell line K562 was examined; revealing three promising compounds PT5, GP2 and GP5 (IC50 5.46, 4.78 and 3.19 μM, respectively). These compounds were shown to inhibit extracellular signal-regulated kinase (ERK) downstream signaling, and induce apoptosis in K562 cells. Among them, PT5 was identified to have in vitro activity (IC50 = 1.44 μM) against ABL1 kinase, about sixfold of 1c, which was justified by molecular docking. The in vitro activities of GP2 and GP5 are less than PT5, hence they were supposed to possess other more mechanisms of cytotoxicity. In general, our design and derivatizations resulted in enhancing the activity against ABL1 kinase and CML cells.

Application of Benzyl Ester of Modified Vegetable Oils as Rubber Processing Oils

2011 ◽  
Vol 415-417 ◽  
pp. 1164-1167 ◽  
Author(s):  
Hasleena Boontawee ◽  
Charoen Nakason ◽  
Azizon Kaesaman ◽  
Anoma Thitithammawong ◽  
Sopa Chewchanwuttiwong
Keyword(s):  
Fatty Acids ◽  
Vegetable Oils ◽  
Dynamic Mechanical Properties ◽  
Benzyl Ester ◽  
Molar Ratio ◽  
Mixing Energy ◽  
Rubber Compounds ◽  
Different Types ◽  
Benzyl Esters ◽  
Hydrolysis Of

Benzyl esters of fatty acids based on three types of vegetable oils (i.e., coconut, palm, and soybean oils) were in-house prepared. They were used as alternative rubber processing oil to replace conventional aromatic oil which has been banned by European community since December 2009. Fatty acids were first prepared by hydrolysis of vegetable oils and thereafter esterified with benzyl alcohol in the presence of sulfuric acid as a catalyst. The reaction based on molar ratio of fatty acid:benzyl alcohol:sulfuric acid was set at 1.5:1.0:0.05 gave yield of benzyl esters higher than 80%. Rubber compounds containing different types of benzyl ester were prepared according to the standard formulation of ASTM 3184. It was found that the processing oil in the form of benzyl esters is possible to use instead of aromatic oil in rubber formulation. Various parameters and properties include mixing energy, Mooney viscosity, curing, mechanical and dynamic mechanical properties of rubber compounds and vulcanizates have been investigated.

scholarly journals E64 [trans-epoxysuccinyl-l-leucylamido-(4-guanidino)butane] analogues as inhibitors of cysteine proteinases: investigation of S2 subsite interactions

1994 ◽  
Vol 299 (2) ◽  
pp. 389-392 ◽  
Author(s):  
B J Gour-Salin ◽  
P Lachance ◽  
M C Magny ◽  
C Plouffe ◽  
R Ménard ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cathepsin B ◽  
Benzyl Ester ◽  
Amide Proton ◽  
Side Chain ◽  
Cysteine Proteinases ◽  
Enzyme Substrate ◽  
Amide Derivatives ◽  
Benzyl Esters ◽  
S2 Subsite

A number of epoxysuccinyl amino acid benzyl esters (HO-Eps-AA-OBzl) and benzyl amides (HO-Eps-AA-NHBzl) (where AA represents amino acid) were synthesized as analogues of E64, a naturally occurring inhibitor of cysteine proteinases. These inhibitors were designed to evaluate if selectivity for cathepsin B could be achieved by varying the amino acid on the basis of known substrate specificity. Contrary to the situation with substrates, it was found that variation of the amino acid in the E64 analogues does not lead to major changes in the kinetic parameter kinac./Ki and that the specificity of these analogues does not parallel that observed for substrates. This is particularly true in the case of the benzyl ester derivatives where the deviation from substrate-like behaviour is more important than with the benzyl amide derivatives. The results suggest that the amide proton of the benzyl amide group in HO-Eps-AA-NHBzl interacts in the S2 subsite in both cathepsin B and papain and contributes to increase the potency of these inhibitors. The kinetic data also suggest that differences in the orientation of the C alpha-C beta bond of the side chain in the S2 subsite of the enzyme might explain the differences between substrate and E64 analogue specificities. This hypothesis is supported by the fact that the order of inactivation rates with chloromethane inhibitors (which are believed to be good models of enzyme-substrate interactions) is indeed very similar to that observed with the corresponding amidomethylcoumarin substrates. In conclusion, the information available from S2-P2 interactions with substrates cannot be used to enhance the selectivity of the E64 analogues in a rational manner.

Nickel atom – ligand reactions: evidence for an unstable η3-benzylnickel species from mixed-ligand cocondensations with nickel atoms

1982 ◽  
Vol 60 (21) ◽  
pp. 2654-2660 ◽  
Author(s):  
J. Stephen Hartman ◽  
Eric C. Kelusky
Keyword(s):  
Metal Atom ◽  
Benzyl Chloride ◽  
Organic Ligand ◽  
Allyl Chloride ◽  
Nickel Atom ◽  
Mixed Ligand ◽  
Benzyl Halide ◽  
Benzyl Halides

Detailed studies of nickel atom – benzyl halide cocondensation reactions, with and without a second organic ligand, have been carried out. Benzyl halides (X = Cl, Br) when cocondensed with nickel atoms at −196 °C give no isolable organonickel product but only bibenzyl and nickel(II) halide, indicative of an initial unstable benzylnickel compound. Allyl chloride/benzyl chloride mixtures do not give the stable η3-allylnickel chloride, but instead a highly-unstable sublimable yellow solid which apparently is the η3-benzylnickel chloride dimer. All of this work indicates complexities in the initial metal atom interactions with the ligands. A further case is reported in which the presence of aluminosilicate insulating wool drastically changes the products obtained.

Un nouvel agent de glycosylation: l'anhydride trifluorométhanesulfonique. Synthèse des α et β O-glycosyl-L-sérine, -L-thréonine et -L-hydroxyproline

1981 ◽  
Vol 59 (2) ◽  
pp. 473-481 ◽  
Author(s):  
J. M. Lacombe ◽  
A. A. Pavia ◽  
J. M. Rocheville
Keyword(s):  
Column Chromatography ◽  
Optical Rotation ◽  
Benzyl Ester ◽  
Experimental Procedure ◽  
Condensation Products ◽  
Benzyl Esters ◽  
Similar Yield ◽  
C Nmr

When 2,3,4,6-tetra-O-benzyl-D-glucopyranose, -D-galactopyranose and 2,3,4-tri-O-benzyl-D-xylopyranose were allowed to react in the cold in dichloromethane or acetonitrile as solvent in the presence of trifluoromethanesulfonic (triflic) anhydride, with methyl or benzyl esters of the N-(benzyloxycarbonyl)-L-serine, -L-threonine, and -L-hydroxyproline, an anomeric mixture of the corresponding O-glycosylaminoacids was obtained (55 to 90% overall yield), with the α-anomer being predominant. The same experimental procedure was successfully applied to the condensation of the benzyl ester of the N-(benzyloxycarbonyl)-L-hydroxyproline with 2,3,4-tri-O-benzyl-L-arabinopyranose and 2,3,5-tri-O-benzyl-L-arabinofuranose affording the corresponding condensation products with similar yield. Pure α and β anomers were obtained after column chromatography or crystallization with 30 to 65% yield. Hydrogenolysis of benzyl derivatives afforded the unprotected compounds. Optical rotation, 1H and 13C nmr were the main methods used to assess structure and stereochemistry.

Influence of Benzyl Ester Oil on Processability of Silica Filled NR Compound

2013 ◽  
Vol 844 ◽  
pp. 221-224 ◽  
Author(s):  
Hasleena Boontawee ◽  
Charoen Nakason ◽  
Azizon Kaesaman ◽  
Anoma Thitithammawong ◽  
Sopa Chewchanwuttiwong
Keyword(s):  
Natural Rubber ◽  
Soybean Oil ◽  
Dynamic Properties ◽  
Benzyl Ester ◽  
Rubber Compound ◽  
Mixing Energy ◽  
Cure Time ◽  
Benzyl Esters ◽  
Mooney Viscosity ◽  
Aromatic Oils

Modified benzyl esters from coconut, palm, and soybean oil were used as alternative rubber processing oil to replace distillate aromatic extract oil (DAE). The effect of benzyl esters on mixing, curing properties, polymerfiller interaction and Mooney viscosity was investigated in silica filled natural rubber compound. Benzyl ester oil was found to be effective processing oil with decreasing of mixing energy and Mooney viscosity. Furthermore, it was found that coconut and palm benzyl esters showed higher torque difference than the aromatic oil filled compound. Also, benzyl ester oil gave similar level of cure time and dynamic properties compared with the rubber compound with aromatic oils.

A convenient preparative method for tryptophan benzyl esters

1975 ◽  
Vol 28 (9) ◽  
pp. 2065 ◽  
Author(s):  
K Williams ◽  
B Halpern
Keyword(s):  
Amino Acid ◽  
Catalytic Hydrogenation ◽  
Synthetic Peptide ◽  
Preparative Method ◽  
Benzyl Ester ◽  
Protecting Groups ◽  
Benzyl Esters

The utilization of amino acid benzyl esters in synthetic peptide procedures offers advantages over the corresponding methyl or ethyl derivatives. Whereas the latter groups must by cleaved by alkaline saponification, the benzyl ester function can be removed by acidolysis or by catalytic hydrogenation under conditions which permit the simultaneous cleavage of N-acyl-protecting groups such as t-Boc or CBzl.*

scholarly journals Zinc (II)-Mediated Selective O-Benzylation of 2-Oxo-1,2-Dihydropyridines Systems

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1784 ◽  
Author(s):  
Qifan Zhou ◽  
Fangyu Du ◽  
Xinjie Liang ◽  
Wenqiang Liu ◽  
Ting Fang ◽  
...  
Keyword(s):  
Natural Products ◽  
Ternary System ◽  
Functional Groups ◽  
Organic Synthesis ◽  
Critical Role ◽  
New Method ◽  
Reaction Conditions ◽  
Highly Effective ◽  
Benzyl Halides ◽  
Synthetic Intermediates

The selective O-benzylation of 2-oxo-1,2-dihydropyridines plays a critical role in organic synthesis of natural products and biological active molecules. Herein we report a novel ternary system of ZnO, ZnCl2 and N,N-diisopropylethylamine (DIEA), that is highly effective for selective O-benzylation of 2-oxo-1,2-dihydropyridines using abundant substituted benzyl halides and related substituted 2-oxo-1,2-dihydropyridines compounds. This process allows access to a variety of O-benzyl products under mild reaction conditions, which are important synthetic intermediates in the protection of functional groups, and represents a new method toward the development for the O-benzylation of 2-oxo-1,2-dihydropyridines.

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