CONJUGATES OF HETEROAROMATIC NITROGEN-COMPRISING COMPOUNDS
The present invention relates to conjugates of ΤΓ-electron-pair-donating heteroaromatic nitrogen-comprising drugs and pharmaceutically acceptable salts thereof, pharmaceutical compositions comprising said conjugates and the use of said conjugates as medic
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Page/Page column 52; 53
(2021/01/22)
Dimensiosolvatic Effects. IV. Topomerization in Alkyl α-Chlorobenzyl Ethers and Insights into Mechanisms of Their Thermolyses
Rates of topomerization in α-chlorobenzyl ethyl ether and its p-methyl as well as p-methoxy derivatives were determined in various solvents by the dynamic NMR method. The topomerization process was deduced to be ionic because the rates are enhanced in polar solvents as well as by electron-donating substituents. Concentration dependence study of the topomerization in carbon tetrachloride revealed that the observed process is unimolecular; the rates are not affected by concentration of the substrate if the concentration is lower than 0.2 mol L-1. The rates of topomerization are smaller for solutions in bulky solvents than in small solvents, the effects being clear for compounds with electron-donating substituents. The key feature of the kinetic parameters is that the entropy of activation is large and negative for all the solvents examined. The reaction mechanisms are discussed on the basis of these data. The effects of the molecular size of the solvent, dimensiosolvatic effects, are attributed to the effectiveness of the solvation in the formation of ion pairs. The results show that thermolyses of alkyl α-chlorobenzyl ethers are much slower reactions than the ionization. The nature of the reaction is discussed.
The Kinetics and Mechanism of the Soft Metal Ion-promoted Hydrolysis of α-Ethoxy-α-ethylthiotoluene in Aqueous Solution
Kinetic studies show that the overall hydrolysis of the open-chain OS-acetal α-ethoxy-α-ethylthiotoluene in aqueous solution, promoted by mercury(II) or by thallium(III) ions, proceeds via rapid desulphurisation to give the hemiacetal, followed by the rate-limiting hydrogen ion-catalysed hydrolysis of the latter.With mercury(II) ions, only in the presence of relatively high concentrations of added chloride ions does the mechanism change.
Penn, David,Satchell, Derek P. N.
p. 1029 - 1030
(2007/10/02)
Syntheses with organic phosphorus compounds. II. PO-activated alkoxyolefin formation
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Grell,Machleidt
p. 53 - 57
(2007/10/08)
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