Reaction of S-geranyl-2-thiouracil modified oligonucleotides with alkyl amines leads to the N2-alkyl isocytosine derivatives

2017 ◽  
Vol 15 (25) ◽  
pp. 5332-5336 ◽  
Author(s):  
Grazyna Leszczynska ◽  
Klaudia Sadowska ◽  
Malgorzata Sierant ◽  
Milena Sobczak ◽  
Barbara Nawrot ◽  
...  
Keyword(s):  
Modified Oligonucleotides ◽  
Alkyl Amine ◽  
Alkyl Amines ◽  
Alkaline Conditions

The yield of the synthesis ofS-geranylated oligomers depends on the alkaline conditions of oligomer deprotection; a routinely used alkyl amine protocol deliversN2-alkylisocytosine-modified side products.

Flotation Behavior Difference between the Pure Quartz and the Quartz Gangue of a Siliceous-Calcareous Phosphate Ore with Fine Size

2013 ◽  
Vol 448-453 ◽  
pp. 3855-3858
Author(s):  
Fang Guo ◽  
Jun Li
Keyword(s):  
Carbon Chain ◽  
Alkaline Condition ◽  
Acid Condition ◽  
Phosphate Ore ◽  
Alkyl Amine ◽  
Alkaline Conditions ◽  
Fine Size ◽  
Ir Analysis ◽  
Adsorption Intensity ◽  
Flotation Behavior

Flotation behavior of pure quartz is difference from that of the quartz gangue of a siliceous-calcareous phosphate ore with fine size. The flotation of pure quartz can attain satisfactory results at alkaline conditions. The IR analysis shows that adsorption intensity of quaternary ammonium salt is stronger which is likely to explain its preferable flotation performance for pure quartz. However, for quartz gangue of phosphate ore, the results are completely opposite. The acid condition is more favorable for reverse flotation than alkaline condition due to the existence of carbonate mineral. The alkyl amine salt is a more effective collector to remove quartz gangue from siliceous-calcareous phosphate ore, especial with 12 carbon chain. Zeta potential of the ore treated by it is almost higher than that by the other alkyl amine salts (with 10, 14 or 18 carbon chain), which suggests its stronger absorption on ore particles.

Cu(ii)–alkyl amine complex mediated hydrothermal synthesis of Cu nanowires: exploring the dual role of alkyl amines

2014 ◽  
Vol 16 (40) ◽  
pp. 22107-22115 ◽  
Author(s):  
D. V. Ravi Kumar ◽  
Inhyuk Kim ◽  
Zhaoyang Zhong ◽  
Kyujin Kim ◽  
Daehee Lee ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Complex Formation ◽  
Dual Role ◽  
Cu Nanowires ◽  
Alkyl Amine ◽  
Alkyl Amines ◽  
Amine Complex ◽  
Nanowire Synthesis

The complex formation of Cu2+ ions with alkyl amines is a prerequisite for Cu nanowire synthesis. Slow reduction of this complex allows for the generation of twinned seeds, which are later grown into nanowires.

A crystalline–amorphous Ni–Ni(OH)2 core–shell catalyst for the alkaline hydrogen evolution reaction

2020 ◽  
Vol 8 (44) ◽  
pp. 23323-23329
Author(s):  
Jing Hu ◽  
Siwei Li ◽  
Yuzhi Li ◽  
Jing Wang ◽  
Yunchen Du ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Electrocatalytic Activity ◽  
Core Shell ◽  
Alkaline Conditions

Crystalline–amorphous Ni–Ni(OH)2 core–shell assembled nanosheets exhibit outstanding electrocatalytic activity and stability for hydrogen evolution under alkaline conditions.

Germination of leucaena and Rhodes grass seeds in saline and alkaline conditions

2016 ◽  
Vol 44 (3) ◽  
pp. 461-474 ◽  
Author(s):  
J.B. Wehr ◽  
P.M. Kopittke ◽  
S.A. Dalzell ◽  
N.W. Menzies
Keyword(s):  
Rhodes Grass ◽  
Alkaline Conditions

PHENOLIC METABOLITES OF DL-NORGESTREL: A METHOD FOR THE REMOVAL OF 1-HYDROXYLATED METABOLITES, POTENTIAL SOURCES OF PHENOLIC ARTIFACTS

1974 ◽  
Vol 76 (4) ◽  
pp. 789-800 ◽  
Author(s):  
Samuel F. Sisenwine ◽  
Ann L. Liu ◽  
Hazel B. Kimmel ◽  
Hans W. Ruelius
Keyword(s):  
Urinary Metabolites ◽  
Ion Exchange Resin ◽  
Gas Chromatography Mass Spectrometry ◽  
Phenolic Metabolites ◽  
Hydroxylated Metabolites ◽  
Analytical Work ◽  
Potential Sources ◽  
Alkaline Conditions ◽  
Artifact Formation ◽  
Work Up

ABSTRACT The identification of 1β-hydroxynorgestrel among the urinary metabolites of dl-norgestrel and the facile transformation of this compound under mild alkaline conditions to a potentially oestrogenic phenol provide an experimental basis for the conclusion advanced by others that the oestrogens present in the urine of subjects treated with synthetic progestens are artifacts formed during analytical work-up. A method has been devised which eliminates 1-hydroxylated metabolites as potential sources of phenolic artifacts. This method is based on the reduction by NaBH4 of the 1-hydroxy-4-en-3-one grouping in the A ring thereby excluding the possibility of aromatization during later fractionation on a basic ion exchange resin that separates neutral from phenolic metabolites. In the urines of women treated with 14C-dl-nogestrel, only 0.17–0.27% of the dose is found to have phenolic properties when this method is used. Two of the phenolic metabolites, 18-homoethynyloestradiol and 16β-hydroxy-18-homoethynyloestradiol, are present in amounts smaller than 0.01 % of the dose. Without the reduction steps the percentages are noticeably higher, indicating artifact formation under alkaline conditions. Similar results were obtained with urines from African Green Monkeys (Cercopithecus Aethiops) that had been dosed with 14C-dl-norgestrel. Radiolabelled 18-homoethynyloestradiol and 16β-hydroxy-18-homoethynyloestradiol were isolated from monkey urine and their identity confirmed by gas chromatography-mass spectrometry.

Screening of an Alkaline CMCase-Producing Strain and the Optimization of its Fermentation Condition

2020 ◽  
Vol 21 (13) ◽  
pp. 1304-1315
Author(s):  
Junmei Zhou ◽  
Lianghong Yin ◽  
Chenbin Wu ◽  
Sijia Wu ◽  
Jidong Lu ◽  
...  
Keyword(s):  
Bacterial Isolate ◽  
Ammonium Oxalate ◽  
Fermentation Condition ◽  
Bivalent Cations ◽  
Rdna Sequencing ◽  
Optimum Ph ◽  
Alkaline Conditions ◽  
Fermentation Parameters ◽  
Pulp And Paper Industries ◽  
Central Composite

Objective: Alkaline Carboxymethyl Cellulase (CMCase) is an attractive enzyme for the textile, laundry, pulp, and paper industries; however, commercial preparations with sufficient activity at alkaline conditions are scarce. Methods: High CMCase-producing bacterial isolate, SX9-4, was screened out from soil bacteria, which was identified as Flavobacterium sp. on the basis of 16S rDNA sequencing. Results: The optimum pH and temperature for CMCase reaction were 8.0 and 55°C, respectively. Alkaline CMCase was stable over wide pH (3.0-10.6) and temperature (25-55°C) ranges. Enzyme activity was significantly inhibited by the bivalent cations Mn2+ and Cu2+, and was activated by Fe2+. To improve the alkaline CMCase production of SX9-4, fermentation parameters were selected through onefactor- at-a-time and further carried out by response surface methodologies based on a central composite design. Conclusion: High CMCase production (57.18 U/mL) was achieved under the optimal conditions: 10.53 g/L carboxymethylcellulose sodium, 7.74 g/L glucose, 13.71 g/L peptone, and 5.27 g/L ammonium oxalate.

Kinetic Behaviour of Amylase According to pH: A New Perspective for Starch Hydrolysis Process

2020 ◽  
Vol 16 (2) ◽  
pp. 135-144
Author(s):  
Ravneet K. Grewal ◽  
Baldeep Kaur ◽  
Gagandeep Kaur
Keyword(s):  
Metal Ions ◽  
Competitive Inhibition ◽  
Deae Cellulose ◽  
Kinetic Studies ◽  
Cost Effective ◽  
Starch Hydrolysis ◽  
Divalent Metal Ions ◽  
Activity Data ◽  
Time Saving ◽  
Alkaline Conditions

Background: Amylases are the most widely used biocatalysts in starch saccharification and detergent industries. However, commercially available amylases have few limitations viz. limited activity at low or high pH and Ca2+ dependency. Objective: The quest for exploiting amylase for diverse applications to improve the industrial processes in terms of efficiency and feasibility led us to investigate the kinetics of amylase in the presence of metal ions as a function of pH. Methods: The crude extract from soil fungal isolate cultures is subjected to salt precipitation, dialysis and DEAE cellulose chromatography followed by amylase extraction and is incubated with divalent metal ions (i.e., Ca2+, Fe2+, Cu2+, and Hg2+); Michaelis-Menton constant (Km), and maximum reaction velocity (Vmax) are calculated by plotting the activity data obtained in the absence and presence of ions, as a function of substrate concentration in Lineweaver-Burk Plot. Results: Kinetic studies reveal that amylase is inhibited un-competitively at 5mM Cu2+ at pH 4.5 and 7.5, but non-competitively at pH 9.5. Non-competitive inhibition of amylase catalyzed starch hydrolysis is observed with 5mM Hg2+ at pH 9.5, which changes to mixed inhibition at pH 4.5 and 7.5. At pH 4.5, Ca2+ induces K- and V-type activation of amylase catalyzed starch hydrolysis; however, the enzyme has V-type activation at 7mM Ca2+ under alkaline conditions. Also, K- and V-type of activation of amylase is observed in the presence of 7mM Fe2+ at pH 4.5 and 9.5. Conclusion: These findings suggest that divalent ions modulation of amylase is pH dependent. Furthermore, a time-saving and cost-effective solution is proposed to overcome the challenges of the existing methodology of starch hydrolysis in starch and detergent industries.

α-Ketophosphonates in the Synthesis of α-iminophosphonates

2020 ◽  
Vol 7 (2) ◽  
pp. 226-238
Author(s):  
Petro P. Ony`sko ◽  
Tetyana I. Chudakova ◽  
Vladimir V. Pirozhenko ◽  
Alexandr B. Rozhenko
Keyword(s):  
Bond Cleavage ◽  
Direct Synthesis ◽  
Equilibrium Mixture ◽  
Primary Amines ◽  
Alkyl Amines ◽  
Protic Solvents ◽  
Metallic Salts ◽  
Direct Preparation ◽  
Stage Synthesis ◽  
Aprotic Dipolar Solvent

The potentialities of condensation of α-ketophosphonates with primary amines for direct synthesis of α-iminophosphonates have been revealed. Diesters of α-ketophosphonic acids react with the primary amines by two competitive pathways: with a formation of α-iminophosphonates or a C-P bond cleavage resulting in a hydrogen phosphonate and an acylated amine. In many cases, the latter undesirable pathway is dominant, especially for more nucleophilic alkyl amines. Using metallic salts of α-ketophosphonates avoids the C-P bond cleavage, allowing direct preparation of α-phosphorylated imines by the reaction with primary amines. This strategy provides an atom economy single-stage synthesis of iminophosphonates – precursors of bio relevant phosphorus analogs of α-amino acids. Methyl sodium iminophosphonates, bearing aryl or heteryl substituents at the imino carbon atom exist in solutions at room temperature as an equilibrium mixture of Z- and E-isomers. A configuration of the C=N bond can be controlled by the solvent: changing the aprotic dipolar solvent DMSO-d6 by water or alcohols leads to the change from a predominant Z-isomer to almost an exclusive E-form. In contrast, diesters of the respective iminophosphonates exist in non-protic solvents predominantly in Econfiguration. The solvent effect on E-Z stereochemistry is demonstrated by DFT calculations.

Click conjugation of 4'-C-modified oligonucleotides

2011 ◽  
Author(s):  
Anu Kiviniemi ◽  
Pasi Virta ◽  
Harri Lönnberg
Keyword(s):  
Modified Oligonucleotides
Sign in / Sign up

Export Citation Format

Share Document