Relationships of the diffusion rates, the limiting currents for the reduction of H+ ions and the pKa values of the polyphenols have been established. Electron-withdrawing substituents increase the diffusion rate of the H+ ions with increasing acidity of the polyphenol; whereas electron-donating ...
Hexaaqua complexes of bivalent Mg, Ca, Mn, Ni, Zn, Cd, and trivalent Al, Ga, In, Sc, Cr, Fe cations were examined. The result is a global linear relationship with regression coefficient r2 = 0.9417 between the pKa values and binding energies in these hexaaqua metal complexes....
pKa - The pKa value is the negative base -10 logarithm of the acid dissociation constant (Ka) of a solution. The quantitative behavior of acids and bases in solution can be understood only if their pKa values are known. To learn more about Calculation o
than 8 when the effect is too strong, easy to produce convulsion effects. In the structure of the N atom on the imide a methyl substituted can reduce acidity and increase fat soluble, more quickly. S is replaced with C-2 bit O. The fat soluble, easily through the blood-brain barrier,...
pKa and pH - The fundamental distinction between pKa and pH is that pKa denotes an acid's dissociation, whereas pH denotes a system's acidity or alkalinity.
1、药物化学构效关系(Structure-activity relationship)BarbituratesBarbiturates are structural nonspecific drugsNonspecific drugs: the biological activity of drugs has little to do with the chemical structure of drugs, and is related to the physical and chemical propertiesStructural specific drugs: the ...
twosubstituentstohaveactivity,whenthe twosubstituents,thetotalnumberofcarbonatomsbetween4 to8,thebestdistributioncoefficientofmoderateactivity. Whenthetotalnumberofcarbonatomsismorethan8whenthe effectistoostrong,easytoproduceconvulsioneffects.In thestructureoftheNatomontheimideamethylsubstituted canreduceacidityand...
Insert - CH2, between benzene ring and carboxyl - O - groups, such as damage to the formation of zwitterionic. Activity. If connected to conjugate groups can be formed, such as - CH2 = CH2 -. Activity can remain the same. Amide also can form the amphoteric ion. In this part, the st...
In fact, the electron donor group increases the acidity of the phenolic hydroxyl group and decreases the pKa value, which is more conducive to proton dissociation and the antioxidant activity. However, the effect of pH on proton dissociation ability is not considered in this calculation. Nevertheles...
therearetwosubstituentsonthe totalnumberofcarbonatomswhentwosubstituentbetween4to 8,thedistributioncoefficientismoderate,activebest.When thetotalnumberofcarbonatomsinmorethaneight,effectis strong,easytoproduceconvulsion.ThestructureoftheNatoms onthemethylontheimidereplacedcanreduceacidityand increasethefatsoluble,work...