scholarly journals 1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

2022 ◽  
Vol 18 ◽  
pp. 53-69
Author(s):  
Ruan Carlos B Ribeiro ◽  
Patricia G Ferreira ◽  
Amanda de A Borges ◽  
Luana da S M Forezi ◽  
Fernando de Carvalho da Silva ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Synthesis ◽  
Sulfonic Acid ◽  
Pharmaceutical Market ◽  
Low Molecular Weight ◽  
Amino Groups ◽  
Pharmacological Targets ◽  
Secondary Amino ◽  
Acid Salts

Several low molecular weight naphthoquinones are very useful in organic synthesis. These compounds have given rise to thousands of other naphthoquinones that have been tested against various microorganisms and pharmacological targets, including being used in the preparation of several drugs that are on the pharmaceutical market. Among these naphthoquinones, the series of compounds prepared from 1,2-naphthoquinone-4-sulfonic acid salts (β-NQS) stands out. In addition to being used in organic synthesis, they are excellent analytical derivatization reagents to spectrophotometrically determine drugs containing primary and secondary amino groups. This review summarizes the literature involving β-NQS.

scholarly journals Biodegradation of low molecular weight polyacrylamide under aerobic and anaerobic conditions: effect of the molecular weight

2020 ◽  
Vol 81 (2) ◽  
pp. 301-308 ◽  
Author(s):  
Wenzhe Song ◽  
Yu Zhang ◽  
Amir Hossein Hamidian ◽  
Min Yang
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Carbon Chain ◽  
Anaerobic Treatment ◽  
Low Molecular Weight ◽  
Amino Groups ◽  
Molecular Weights ◽  
Weight One ◽  
Hydrolysis Of ◽  
Aerobic And Anaerobic

Abstract The biodegradation of polyacrylamide (PAM) includes the hydrolysis of amino groups and cleavage of the carbon chain; however, the effect of molecular weight on the biodegradation needs further investigations. In this study, biodegradation of low molecular weight PAM (1.6 × 106 Da) was evaluated in two aerobic (25 °C and 40 °C) and two anaerobic (35 °C and 55 °C) reactors over 100 days. The removal of the low molecular weight PAM (52.0–52.6%) through the hydrolysis of amino groups by anaerobic treatment (35 °C and 55 °C) was much higher than that of the high molecular weight (2.2 × 107 Da, 11.2–17.0%) observed under the same conditions. The molecular weight was reduced from 1.6 × 106 to 6.45–7.42 × 105 Da for the low molecular weight PAM, while the high molecular weight PAM declined from 2.2 × 107 to 3.76–5.87 × 106 Da. The results showed that the amino hydrolysis of low molecular weight PAM is easier than that of the high molecular weight one, while the cleavage of its carbon chain is still difficult. The molecular weights of PAM in the effluents from the two aerobic reactors (25 °C and 40 °C) were further reduced to 4.31 × 105 and 5.68 × 105 Da by the biofilm treatment, respectively. The results would be useful for the management of wastewater containing PAM.

Immunometric assay of low molecular weight haptens containing primary amino groups

1994 ◽  
Vol 66 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Philippe. Pradelles ◽  
Jacques. Grassi ◽  
Christophe. Creminon ◽  
Bruno. Boutten ◽  
Suzanne. Mamas
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Amino Groups ◽  
Immunometric Assay ◽  
Primary Amino

The Retrieval and Use of Components from AMPS Production Residue

2011 ◽  
Vol 356-360 ◽  
pp. 2060-2064
Author(s):  
Hai Jing Wang ◽  
Jin Sheng Feng
Keyword(s):  
Molecular Weight ◽  
Sulfonic Acid ◽  
Raw Materials ◽  
Low Molecular Weight ◽  
Surface Active Agents ◽  
External Standard Method ◽  
Reinforcing Agent ◽  
External Standard ◽  
Surface Active ◽  
Flocculating Agent

2-acrylamido-2-methylpropane sulfonic acid (AMPS) is commonly used in the synthesis of polyacrylamide which is widely used as surface-active agents, water treatment chemicals and oil-displacing agents. In the production process of AMPS, there are some byproducts. In this paper, the residue from AMPS production is analyzed. The main byproducts in the residue are ascertained by means of HPLC and ESI-MS, which are butylacrylamide (TBAA) and acrylamide. By external standard method, the residue is analyzed quantitatively. Using the residue as raw materials, a kind of polyacrylamide with low molecular weight is synthesized, which can be used as paper reinforcing agent or emulsifier. After the residue is purified, the high molecular weight polyacrylamide is synthesized, which can be used as flocculating agent or oil-displacing agent.

scholarly journals Synthesis of a Chiral Meso-Like Ansa-Zirconocene Complex and its Use for the Catalytic Formation of Low Molecular Weight Polypropylene

1995 ◽  
Vol 50 (6) ◽  
pp. 982-989 ◽  
Author(s):  
Sven Thiele ◽  
Gerhard Erker ◽  
Cornelia Fritze ◽  
Christian Psiorz ◽  
Roland Fröhlich
Keyword(s):  
Crystal Structure ◽  
Molecular Weight ◽  
Double Bond ◽  
Ambient Temperature ◽  
Organic Synthesis ◽  
Crystal Structure Analysis ◽  
Low Molecular Weight ◽  
X Ray ◽  
Catalyst Systems ◽  
Double Bond Shift

Reaction of lithium(neomenthylcyclopentadienid) 3 with dimethyldichlorosilane gives dimethylbis[3-(neomenthyl)cyclopentadienyl]silane 4 regioselectively as a mixture of double bond shift isomers (57% isolated). Deprotonation with 2 equiv. of butyllithium followed by treatment with zirconiumtetrachloride furnished a mixture of the three {dimethylsilylenbis[η5-3-(neomenthyl)cyclopentadienyl][zirconium dichloride diastereomers from which the pure meso-like isomer 6e [p -R (1′S ,3 ′R ,4 ′R),p -S (1′S ,3 ′R ,4 ′R)] was isolated by fractional crystallization. Complex 6 c was characterized by an X-ray crystal structure analysis. Its D 1 - Zr - D 2 angle of 126.8° is very similar as observed in bis(η-cyclopentadienyl) zirconium dichloride (D 1 and D 2 denote the centroids of the cyclopentadienyl rings). The homogeneous 6c/methylalumoxane Ziegler-type catalyst produces polypropylene of low molecular weight (Mη ≈ 670 at ambient temperature). Related catalyst systems may find interesting applications in organic synthesis.

Low molecular weight MPEG-assisted organic synthesis

2010 ◽  
Vol 46 (24) ◽  
pp. 4405 ◽  
Author(s):  
Marek Figlus ◽  
Albert C. Tarruella ◽  
Anastasia Messer ◽  
Steven L. Sollis ◽  
Richard C. Hartley
Keyword(s):  
Molecular Weight ◽  
Organic Synthesis ◽  
Low Molecular Weight

Different orientations of low-molecular-weight fragments in the binding pocket of a BRD4 bromodomain

2013 ◽  
Vol 69 (10) ◽  
pp. 2161-2164 ◽  
Author(s):  
Graziano Lolli ◽  
Roberto Battistutta
Keyword(s):  
Molecular Weight ◽  
Binding Pocket ◽  
Low Molecular Weight ◽  
Chromatin Architecture ◽  
Pharmacological Targets ◽  
Crystallographic Structures

Bromodomains are involved in the regulation of chromatin architecture and transcription through the recognition of acetylated lysines in histones and other proteins. Many of them are considered to be relevant pharmacological targets for different pathologies. Three crystallographic structures of the N-terminal bromodomain of BRD4 in complex with low-molecular-weight fragments are presented. They show that similar molecules mimicking acetylated lysine bind the bromodomain with different orientations and exploit different interactions. It is also advised to avoid DMSO when searching for low-affinity fragments that interact with bromodomains since DMSO binds in the acetylated lysine-recognition pocket of BRD4.

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