Silver Acetate as an Amphoteric Base.

1951 ◽  
Vol 55 (8) ◽  
pp. 1299-1302 ◽  
Author(s):  
Sigfred Peterson ◽  
Edward K. Dienes
Keyword(s):  
1992 ◽  
Vol 70 (10) ◽  
pp. 2618-2626 ◽  
Author(s):  
Marek Majewski ◽  
Guo-Zhu Zheng

Tropinone (6) was deprotonated with lithium diisopropylamide and with chiral lithium amides (18–24) and the resulting enolates (two enantiomers) were treated with electrophiles. The aldol reaction with benzaldehyde and deuteration were both diastereoselective. The former yielded only one isomer (exo, anti) of the aldol 8a; the latter proceeded from the exo face. This selectivity permitted us to probe the deprotonation of tropinone with lithium amides; it was concluded that the reaction involves predominantly the exo axial protons. The reaction of tropinone enolate with ethyl chloroformate led, via a ring opening, to the cycloheptenone derivative 9. The reaction with methyl cyanoformate yielded, in the presence of silver acetate and acetic acid, the β-ketoester 8b; however, in the absence of these additives, and especially when 12-crown-4 was added to the enolate, a ring opening leading to the pyrrolidine derivative 10 occurred instead. Deprotonation of tropinone with chiral lithium amides proceeded with modest enantioselectivity. A synthesis of non-racemic anhydroecgonine via this strategy allowed establishing the absolute stereochemistry of deprotonation.


Tetrahedron ◽  
1999 ◽  
Vol 55 (7) ◽  
pp. 2025-2044 ◽  
Author(s):  
Ronald Grigg ◽  
Mark I. Lansdell ◽  
Mark Thornton-Pett
Keyword(s):  

1964 ◽  
Vol 42 (3) ◽  
pp. 532-538 ◽  
Author(s):  
R. U. Lemieux ◽  
B. Fraser-Reid

The bromination of D-glucal triacetate gave a mixture of tri-O-acetyl-2-bromo-2-deoxyglycopyranosyl bromides containing about 60% and 30% of the compounds with the α-D-gluco and α-D-manno configurations, respectively. Reaction of the bromides with methanol in the presence of silver carbonate proceeded almost entirely with inversion of the reacting anomeric centers. Hydrogenolysis of the product of methanolysis gave methyl 2-deoxy-β-D-glucopyranoside. Reaction of D-glucal triacetate with either bromine, chlorine, or iodine in methanol containing silver acetate gave in each case about 60–65% and 35–40% yields of the corresponding methyl 2-deoxy-2-halogeno-α-D-mannopyranoside and -β-D-glucopyranoside triacetates. The mechanisms of the reactions are discussed.


1984 ◽  
Vol 62 (9) ◽  
pp. 1840-1844 ◽  
Author(s):  
Karl R. Kopecky ◽  
Alan J. Miller

Treatment of methyl hydrogen decahydro-1,4:5,8-exo,endo-dimethanonaphthalene-4a,8a-dicarboxylate with lead tetraacetate in benzene – acetic acid replaces the carboxyl group by an acetoxy group. Hydrolysis of this product with 25% sulfuric acid at 130 °C forms 8a-hydroxydecahydro-1,4:5,8-exo,endo-dimethanonaphthalene-4a-carboxylic acid 10. The reaction between 10 and benzenesulfonyl chloride in pyridine containing triethylamine at 95 °C produces anti-sesquinorbornene 1 in 34% yield. In the absence of triethylamine 1 is converted to the hydrochloride. The iodohydroperoxide of 1 is converted by silver acetate at 0 °C to the diketone in a luminescent reaction. The 1,2-dioxetane could not be isolated. Decahydro-1,4:5,8-exo,exo-dimethanonaphthalene-4a,8a-dicarboxylic anhydride is converted slowly by methoxide ion in methanol at 150 °C to the monomethyl ester which then undergoes demethylation. The isomeric exo,endo anhydride undergoes reaction readily with methoxide ion at 80 °C.


2021 ◽  
pp. 58-62
Author(s):  
Dmitrii I. Belenkii ◽  
Dmitry V. Averkin ◽  
Dmitry V. Vishnevetskii ◽  
Svetlana D. Khizhnyak ◽  
Pavel M. Pakhomov

A comprehensive study to develop and create standard samples of the zeta potential unit of particles in a liquid in accordance with the requirements of GOST ISO 13099-2-2016 in the range of measured values from minus 150 mV to plus 150 mV was carried out. The existing standard samples of zeta potential in Russia and the world have been investigated; the analysis of the applicability of the starting materials and components for the creation of new standard samples has done. Samples based on modified polystyrene latex microspheres, bovine serum albumin and supramolecular systems based on aqueous solutions of L-cysteine, N-acetylcysteine, and silver acetate were considered as promising standard samples of the zeta potential of particles. All studies were carried out on equipment from the State Primary Standard of Dispersed Parameters of Aerosols, Suspensions and Powder Materials GET 163-2020 using the method of electrophoretic light scattering and measuring the pH value. It was found that polystyrene latex microspheres do not correspond to the requirements of the work in terms of developing a set of standard samples. Samples based on suspensions of bovine serum albumin do not correspond to the requirements of GOST ISO 13099-2-2016. Supramolecular systems based on aqueous solutions of L-cysteine, N-acetylcysteine, and silver acetate were proposed as standard samples. Such systems are characterized by the ability to modify the initial potential-determining layer of particles without changing their aggregate stability. Studies of the long-term stability of the developed standard samples of the zeta-potential unit of particles in a liquid have been carried out.


CHEST Journal ◽  
1986 ◽  
Vol 90 (1) ◽  
pp. 107-111 ◽  
Author(s):  
Robert Malcolm ◽  
Hal S. Currey ◽  
Mary Ann Mitchell ◽  
Julian E. Keil
Keyword(s):  

2007 ◽  
Vol 90 (3) ◽  
pp. 813-816 ◽  
Author(s):  
V. Logvinenko ◽  
O. Polunina ◽  
Yu. Mikhailov ◽  
K. Mikhailov ◽  
B. Bokhonov

Author(s):  
Анна Нориковна Адамян ◽  
Алена Константиновна Кучурова ◽  
Александра Ивановна Иванова ◽  
Максим Дмитриевич Малышев ◽  
Виктор Анатольевич Герасин ◽  
...  

Выполнены реологические, структурные и антибактериальные исследования гидрогелей, получаемых на основе L-цистеина, ацетата серебра и полигексаметиленгуанидин гидрохлорида (ПГМГ-ГХ). Установлено, что водные растворы на основе L-цистеина и ацетата серебра хорошо смешиваются с водным раствором ПГМГ-ГХ, образуя прозрачные гидрогели. Предложена модель строения пространственной сетки геля. Показана высокая антимикробная активность гидрогеля по отношению к тест-культурам патогенных и условно-патогенных микроорганизмов. Rheological, structural, and antibacterial studies of hydrogels based on L-cysteine, silver acetate, and polyhexamethylene guanidine hydrochloride (PHMG-GC) have been carried out. It was found that aqueous solutions based on L-cysteine and silver acetate mix well with an aqueous solution of PHMG-GC, forming transparent hydrogels. A model of the structure of the spatial grid of the gel is proposed. High antimicrobial activity of the hydrogel was shown in relation to test cultures of pathogenic and opportunistic microorganisms.


Sign in / Sign up

Export Citation Format

Share Document