Synthesis and Acylation of 4-Chloroalkyl-3,4-dihydropyrimidin-2(1H)- ones

2012 ◽  
Vol 67 (9) ◽  
pp. 921-924 ◽  
Author(s):  
Maksim A. Kolosov ◽  
Olesia G. Kulyk ◽  
Muataz Al-Ogaili ◽  
Valeriy D. Orlov
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
Building Blocks ◽  
Low Molecular Weight ◽  
One Pot ◽  
Acid Anhydrides ◽  
Acyl Derivatives

4-Chloroalkyl-3,4-dihydropyrimidin-2(1H)-ones are useful multifunctional 3,4-dihydropyrimidine building blocks with low molecular weight and sufficient solubility, which may be modified selectively by substituents in different positions. Here we propose a simple one-pot protocol for the synthesis of these compounds, which is based on the use of common reagents viz. urea, chloroaliphatic aldehydes and 3-ketoesters. Acylation of 4-chloroalkyl-3,4-dihydropyrimidin-2(1H)-ones by carboxylic acid anhydrides leads to 3-acyl derivatives

scholarly journals Harnessing Chemical Energy for the Activation and Joining of Prebiotic Building Blocks

2019 ◽  
Author(s):  
Ziwei Liu ◽  
Long-Fei Wu ◽  
Jianfeng Xu ◽  
Claudia Bonfio ◽  
David Russell ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Carboxylic Acid ◽  
Peptide Nucleic Acid ◽  
Reactive Intermediates ◽  
Building Blocks ◽  
Acid System ◽  
Rna Oligomers ◽  
Prebiotic Activation ◽  
Simultaneous Activation ◽  
Acid Anhydrides

Simultaneous activation of carboxylates and phosphates provides multiple pathways for the generation of reactive intermediates, including mixed carboxylic acid-phosphoric acid anhydrides, for the synthesis of peptidyl-RNAs, peptides, RNA oligomers and primordial phospholipids. These results indicate that unified prebiotic activation chemistry could have enabled the joining of building blocks in aqueous solution from a common pool and enabled the progression of a system towards higher complexity foreshadowing the modern encapsulated peptide-nucleic acid system

scholarly journals Biologically active ion exchange (BIEX) for NOM removal and membrane fouling prevention

2017 ◽  
Vol 17 (4) ◽  
pp. 1178-1184 ◽  
Author(s):  
M. Schulz ◽  
J. Winter ◽  
H. Wray ◽  
B. Barbeau ◽  
P. Bérubé
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Ion Exchange ◽  
Membrane Fouling ◽  
Building Blocks ◽  
Biologically Active ◽  
Low Molecular Weight ◽  
Effective Removal ◽  
Pre Treatment ◽  
The Impact

The natural organic matter (NOM) removal efficiency and regeneration behavior of ion-exchange filters with promoted biological activity (BIEX) was compared to operation where biological activity was suppressed (i.e. abiotic conditions). The impact of BIEX pre-treatment on fouling in subsequent ultrafiltration was also investigated. Biological operation enhanced NOM removal by approximately 50% due to an additional degradation of smaller humic substances, building blocks and low molecular weight acids. Promotion of biological activity significantly increased the time to breakthrough of the filters and, therefore, is expected to lower the regeneration frequency as well as the amount of regenerate of which to dispose. Pre-treatment using BIEX filters resulted in a significant decrease in total and irreversible fouling during subsequent ultrafiltration. The decrease was attributed to the effective removal of medium and low molecular weight NOM fractions. The results indicate that BIEX filtration is a robust, affordable and easy-to-operate pre-treatment approach to minimize fouling in ultrafiltration systems and enhance the quality of the produced permeate.

scholarly journals Cavity-containing supramolecular gels as a crystallization tool for hydrophobic pharmaceuticals

2016 ◽  
Vol 52 (66) ◽  
pp. 10113-10116 ◽  
Author(s):  
Lena Kaufmann ◽  
Stuart R. Kennedy ◽  
Christopher D. Jones ◽  
Jonathan W. Steed
Keyword(s):  
Molecular Weight ◽  
Building Blocks ◽  
Low Molecular Weight ◽  
Supramolecular Gels

We present two approaches to low-molecular-weight supramolecular gels bearing hydrophobic cavities based on calixarene-containing building blocks.

scholarly journals Iron Catalyzed Synthesis and Chemical Recycling of Telechelic, 1,3-Enchained Oligocyclobutanes

2020 ◽  
Author(s):  
Megan Mohadjer Beromi ◽  
C. Rose Kennedy ◽  
Jarod M. Younker ◽  
Alex E. Carpenter ◽  
Sarah J. Mattler ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Closed Loop ◽  
Building Blocks ◽  
Plastic Waste ◽  
Low Molecular Weight ◽  
Chemical Recycling ◽  
Thermally Stable ◽  
Hydrocarbon Feedstock ◽  
High Crystallinity

Closed-loop recycling offers the opportunity to help mitigate plastic waste through reversible polymer construction and deconstruction. While examples of the chemical recycling polymers are known, few have been applied to materials derived from abundant commodity olefinic monomers that are the building blocks of ubiquitous plastic resins. Here we describe a [2+2] cycloaddition oligomerization of 1,3-butadiene to yield a previously unrealized telechelic microstructure of (1,n’-divinyl)oligocyclobutane. This material is thermally stable, has stereoregular segments arising from chain-end control, and exhibits high crystallinity even at low molecular weight. Exposure of the oligocyclobutane to vacuum in the presence of the pyridine(diimine) iron precatalyst used to synthesize it resulted in deoligomerization to generate pristine butadiene, demonstrating a rare example of closed-loop chemical recycling of an oligomeric material derived from a commodity hydrocarbon feedstock.

scholarly journals 2,1-Benzisothiazoles. XI. The rearrangement of 2,1-Benzisothiazol-3-yl esters. Autocatalysis of a sulfur extrusion by low-molecular-weight sulfur

1981 ◽  
Vol 34 (4) ◽  
pp. 755 ◽  
Author(s):  
M Davis ◽  
KC Tonkin
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Sulfur Addition ◽  
Derivatives Of ◽  
Acyl Derivatives

The extrusion of sulfur from acyl derivatives of 2,1-benzisothiazol-3(1H)-one (1) is autocatalytic. The catalyst is low-molecular-weight sulfur. Addition of cyclohexasulfur (5) to solutions of theseacyl derivatives increases the rate of such reactions.

Efficient synthesis of the nonamannoside residue of high mannose glycoproteins

2005 ◽  
Vol 83 (6-7) ◽  
pp. 693-701 ◽  
Author(s):  
Lu Jiang ◽  
Tak Hang Chan
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Key Words ◽  
Building Blocks ◽  
Polymer Support ◽  
Low Molecular Weight ◽  
Oligosaccharide Synthesis ◽  
Efficient Synthesis ◽  
Solution Synthesis ◽  
High Mannose

An efficient synthesis of the nonamannoside residue 1 of high mannose glycoproteins was achieved using an oligomer-supported solution synthesis with low-molecular-weight polyethylene glycol as the anchor. The synthesis required only five coupling steps from only two monosaccharide building blocks with an overall yield of 12%.Key words: nonamannoside, oligosaccharide synthesis, soluble polymer support synthesis, glycoproteins.

scholarly journals Synthesis and characterization of pH responsive D-glucosamine based molecular gelators

2014 ◽  
Vol 10 ◽  
pp. 3111-3121 ◽  
Author(s):  
Navneet Goyal ◽  
Hari P R Mangunuru ◽  
Bargav Parikh ◽  
Sonu Shrestha ◽  
Guijun Wang
Keyword(s):  
Molecular Weight ◽  
Building Blocks ◽  
Negative Influence ◽  
Low Molecular Weight ◽  
Ph Responsive ◽  
Triggered Release ◽  
Self Assembling ◽  
Potential Applications ◽  
Low Molecular Weight Gelators ◽  
Neutral Conditions

Small molecular gelators are a class of compounds with potential applications for soft biomaterials. Low molecular weight hydrogelators are especially useful for exploring biomedical applications. Previously, we found that 4,6-O-benzylidene acetal protected D-glucose and D-glucosamine are well-suited as building blocks for the construction of low molecular weight gelators. To better understand the scope of D-glucosamine derivatives as gelators, we synthesized and screened a novel class of N-acetylglucosamine derivatives with a p-methoxybenzylidene acetal protective group. This modification did not exert a negative influence on the gelation. On the contrary, it actually enhanced the gelation tendency for many derivatives. The introduction of the additional methoxy group on the phenyl ring led to low molecular weight gelators with a higher pH responsiveness. The resulting gels were stable at neutral pH values but degraded in an acidic environment. The release profiles of naproxen from the pH responsive gels were also analyzed under acidic and neutral conditions. Our findings are useful for the design of novel triggered release self-assembling systems and can provide an insight into the influence of the the structure on gelation.

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