Imidazolylbenzopyrane derivatives: a new class of acyl-CoA: cholesterol acyltransferase (ACAT) inhibitors

Chemical modifications and transformations of 3-azahetarylchroman-4-ones

Articles reporting on the chemical modifications and transformations of 3-azahetarylchroman-4-ones are rewieved. The following 3-azahetarylchroman-4-ones’ transformation - reduction of 3-azahetarylchromon-4-ones to the corresponding 3-azahetarylchromanols, -chromenes, and -3,4-dihydrochromenes, alkylation of 3-azahetarylchromanols, reconversion into 3-azahetarylchromones, formation of 3-hetarylchroman-4-one oximes and corresponding oxime ethers, recyclization into 3-aryl-4-hetarylpyrazolines are described. The biological activity of 3-azahetarylchroman-4-one modification or transformation products are also adduced.

Influence of membrane partitioning on inhibitors of membrane-bound enzymes

Membrane-water partitioning of inhibitors of acyl-coenzyme A:cholesterol acyltransferase (ACAT) governs the concentration of inhibitor that ACAT is exposed to and determines the corresponding extent of cholesterol esterification inhibition. Partitioning of the ACAT inhibitors CI-976, CL 277,082, and SaH 58-035 into rat liver microsomes containing ACAT was detected by shifts in the level of inhibition that were independent of inhibitor concentration but inversely dependent on microsome membrane concentration. The equilibrium distribution of the ACAT inhibitors between aqueous and membrane phases was derived directly from these data by application of a previously described method of linear analysis. The accuracy of membrane partitioning analysis based on kinetic data was verified for CI-976 by direct measurements of [14C]CI-976 partitioning into phospholipid membranes. The results show that the ACAT inhibitors are highly partitioned into membranes by factors exceeding 1 x 10(6). This result is consistent with the far greater influence of membrane content over aqueous volume on inhibitor activity. The results demonstrate that the size of the membrane phase in aqueous suspension must be taken into account to obtain accurate and reproducible kinetic characterizations of membrane-active molecules. Analyses of the membrane-dependent shifts in activity can be used to calculate the membrane-water partitioning coefficient of membrane-active molecules such as ACAT inhibitors.

Prediction of IC50 values for ACAT inhibitors from molecular structure

A quantitative structure-activity study is performed on several series of compounds derived from N-chlorosulfonyl isocyanate to develop models that relate their structures to IC50 activity for inhibition of acyl-CoA:cholesterol O-acyltransferase (ACAT). Numerical descriptors are used to encode topological, electronic, and geometric information from the molecular structures of the inhibitors. A data set of 157 compounds showing triglyceride- and cholesterol-lowering activity is used to develop successful linear regression models and nonlinear computational neural network models. The models are validated using an external prediction set.