Conformers and internal rotation barriers in nitrous acid esters. Low-resolution microwave spectroscopic studies

1982 ◽  
Vol 86 (13) ◽  
pp. 2327-2336 ◽  
Author(s):  
Nancy S. True ◽  
Robert K. Bohn
Keyword(s):  
Internal Rotation ◽  
Nitrous Acid ◽  
Spectroscopic Studies ◽  
Low Resolution ◽  
Acid Esters

scholarly journals Ultrasound-Assisted Method for the Synthesis of Tertiary Fatty Aliphatic Esters with Potential Antimicrobial Activity

2020 ◽  
Vol 10 (6) ◽  
pp. 6829-6836
Keyword(s):  
Fatty Acid ◽  
Reaction Time ◽  
Conventional Method ◽  
Ultrasonic Irradiation ◽  
Spectroscopic Studies ◽  
Fatty Acid Esters ◽  
Aliphatic Esters ◽  
Ultrasound Assisted ◽  
The Impact ◽  
Acid Esters

This study aims to demonstrate a simple and rapid “green” method for the ultrasound-assisted synthesis of t-aliphatic esters by reacting t -butanol with saturated (capric, lauric, palmitic) and unsaturated (oleic and undecylenic) acids. The spectral characterization of esters was performed by IR and NMR spectroscopies. The impact of ultrasonic irradiation on the reaction in comparison with the conventional method was analyzed based on the reaction time and the yield of the resulting esters. After spectroscopic studies, the synthesis of the corresponding esters after the ultrasound-assisted irradiation was proven. The yields of the t-butyl fatty acid esters increased between 2 and 10% in comparison with the conventional method for their synthesis. It was also established that the application of ultrasonic irradiation intensifies the esterification process significantly compared to the conventional method. The advantages of the ultrasound-assisted esterification include shortening the reaction time; the process is carried out at room temperature instead of at the conventional reaction temperature 67-70oC. The application of ultrasonic-assisted irradiation for esterification is a suitable and promising method to reduce energy consumption, shortening the reaction time, and increasing the yield of t -butyl fatty acid esters.

scholarly journals Synthesis, Fluorescence and NMR Spectroscopic Studies of a Novel Phosphinoxido-18-crown-6 Ether Containing an Anthracene Fluorophore Unit

2019 ◽  
Vol 64 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Hajnalka Szabó-Szentjóbi ◽  
Anna Márton ◽  
Dávid Pál ◽  
Gergő Dargó ◽  
Áron Szigetvári ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Spectroscopic Studies ◽  
Primary Amines ◽  
Methyl Groups ◽  
Amino Acid Esters ◽  
Two Dimensional ◽  
Fluorescent Chemosensors ◽  
One Dimensional ◽  
Stereogenic Centers ◽  
Acid Esters

The synthesis of the (R,R) and (S,S) enantiomers of a new enantiopure monophospha-18-crown-6 ether (1), which contains an anthracene fluorophore unit and methyl groups at its stereogenic centers, was accomplished. The structure of one enantiomer ((S,S)-1) was studied using one-dimensional (1H, 13C{1H}, and 31P{1H}) and two-dimensional NMR spectra. Because (R,R)-1 and (S,S)-1 can act as new fluorescent chemosensors, we examined their enantiomeric differentiation abilities toward the enantiomers of protonated chiral primary amines and amino acid esters (PEA, 1-NEA, PGME, PAME) using UV-Vis and fluorescence spectroscopies. These monophospha-crown ethers showed moderate enantiomeric discrimination abilities.

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