Lipophilic entity

From Table 4.1. one may evidently observe that a entire moleeule of a local anaesthetic has been judiciously divided into three distinct compartments/zones, otherwise termed as lipophilic entity, intermediate chain and hydrophilic entity. However these three zones have been clearly illustrated in a few typical examples e.g., Lidocaine, Tetracaine, Butacaine, Procaine and a cholinergic agent Acetylcholine. 

Alkylation of S-Anions. Aliphatic and aromatic thiols are relatively acidic compounds and can be efficiently deprotonated with anhydrous K2CO3 or moderately concentrated aqueous NaOH. Since the thiolate anions are rather lipophilic entities, the ion-exchange equilibrium 14a is favorable for transfer of these ions into the organic phase. For this reason, PTC is a method of choice for synthesis of sulfides (eqs. 31-34). 

Different balance between intermolecular forces can be accessible via partition coefficients measured in solvents systems other than the traditional 1-octanol/water. Therefore there was a growing interest in the partition processes in several solvent/ water systems [64, 65] and in particular the critical quartet of solvents which was designed to merge the main information about a solute concerning its partition and transport. Only a few studies have been performed to characterize the lipophilicity profile of new chemical entities in different solvent/water systems and consequently the number of methods attempting to model such partitioning systems is limited. 

Lipidic prodrugs are chemical entities with two distinct parts a drug covalently bound to a lipid moiety, i.e., a fatty acid, a glyceride, or a phospholipid. As a result, the lipophilicity of the prodrug compared to the drug is increased. 

For dynamic processes involving hydrogen-bonded entities, see (a) Calama MC et al (1998) Libraries of non-covalent hydrogen-bonded assemblies combinatorial synthesis of supramolecular systems. Chem Commun 1021-1022. (b) Timmerman P et al. (1997) Noncovalent assembly of functional groups on Calix[4]arene molecular boxes. Chem Eur J 3 1823-1832. (c) Cai MM et al. (2002) Cation-directed self-assembly of lipophilic nucleosides the cation s central role in the structure and dynamics of a hydrogen-honded assembly. Tetrahedron 58 661-671... 

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