Quaternary ammonium salts and arginine are inhibitors of general amino acid permease in yeast

1995 ◽  
Vol 43 (2) ◽  
pp. 169-171 ◽  
Author(s):  
Tadeusz M. Lachowicz ◽  
Jerzy Piatkowski ◽  
Stanislaw Witek
Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2463
Author(s):  
Jacqueline Bitai ◽  
Alexandra M. Z. Slawin ◽  
David B. Cordes ◽  
Andrew D. Smith

The scope and limitations of a tandem N-allylation/[2,3]-rearrangement protocol are investigated through the incorporation of a variety of functional groups within an allylic phosphate precursor. This method uses readily accessible N,N-dimethylglycine aryl esters and functionalized allylic phosphates, forming quaternary ammonium salts in situ in the presence of a palladium catalyst. Subsequent enantioselective [2,3]-sigmatropic rearrangement, promoted by the chiral isothiourea tetramisole, generates α-amino acid derivatives with two contiguous stereocenters. The incorporation of electron-withdrawing ester and amide groups gave the best results, furnishing the desired products in moderate to good yields (29–70%), with low diastereocontrol (typically 60:40 dr) but high enantioselectivity (up to 90:10 er). These results indicate that substrate–catalyst interactions in the proposed transition state are sensitive to the substitution pattern of the substrates.


Author(s):  
Tomasz K. Olszewski ◽  
Anna Brol

An effective protocol for quaternization of simple 1-aminoalkylphosphonic acids under basic conditions and using Me2SO4 as convenient alkylating agent is reported. In the course of reaction phosphonic acid quaternary ammonium...


Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2424 ◽  
Author(s):  
Tăbăcaru ◽  
Botezatu ◽  
Horincar ◽  
Furdui ◽  
Dinică

A family of fifteen quaternary ammonium salts (QAs), bearing the 1,2-bis(4-pyridyl)ethane core, were obtained using for the first time two different green methods, such as microwave (MW) and ultrasounds (US) irradiation, with very good yields and in much shorter times compared to the classical method, and an assay on their antimicrobial action against Escherichia coli (E. coli) was carried out. While 12 to 24 hours were required for complete alkylation of 1,2-bis(4-pyridyl)ethane by reactive halogenated derivatives in anhydrous solvent under reflux conditions, MW and US irradiation reduced the reaction time and the desired products were achieved in a few min. One of the aims of this study was to evaluate the antibacterial potential of the synthesized QAs against pathogenic bacteria, along with their impact on germination activity of wheat seeds (Triticum aestivum L.). The antibacterial activity of the QAs against Escherichia coli was explored by determining the minimum inhibitory concentration (MIC). The MIC values varied from 0.312 to 2.5 mg/mL, highlighting the lowest values attained for the derivatives containing methoxy, chlorine and benzofurane functional groups. The viability of aerobic bacteria was determined with the Tetrazolium/Formazan Test, a method that was found to be the best alternative approach with respect to the difuzimetric method. Seeds of Triticum aestivum L. were used for the evaluation of the germination indicators, such as seed germination (SG), the relative seed germination (RSG), the relative radicle growth (RRG), and the seed germination index (GI). The toxicity studies of QAs 1, 4 and 7, at two different concentrations, showed no inhibitory effect on seed germination.


1996 ◽  
Vol 32 (6) ◽  
pp. 331-334
Author(s):  
V. V. Turov ◽  
O. A. Zaporozhets ◽  
O. Yu. Nadzhafova ◽  
V. V. Sukhan

Nature ◽  
1948 ◽  
Vol 161 (4097) ◽  
pp. 718-718 ◽  
Author(s):  
R. B. BARLOW ◽  
H. R. ING

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