1,5-Asymmetric induction in boron-mediated aldol reactions of beta-alkoxy methylketones.

Good levels of substrate-controlled, 1,5- syn-stereoinduction are obtained in boron-mediated aldol reactions of beta-trichloromethyl-beta-alkoxy and beta-trifluoromethyl-beta-alkoxy methylketones with achiral aldehydes, independent of the nature of the beta-alkoxy protecting group (TBS or PMB). In the case of boron aldol reactions of beta-aryl-beta-alkoxy methylketones, the 1,5- anti-adducts were obtained with high levels of diastereoselectivity only with a beta-OPMB group.

The influence of a beta-electron withdrawing substituent in aldol reactions of methylketone boron enolates.

We wish to describe here that good levels of substrate-based, 1,5-syn-stereocontrol could be achieved in the boron-mediated aldol reactions of beta-trichloromethyl methylketones with achiral aldehydes, independent of the nature of the beta-alkoxy protecting group.

Inhibition of horseradish peroxidase catalytic activity by new 3-phenylcoumarin derivatives: synthesis and structure-activity relationships.

Twenty hydroxylated and acetoxylated 3-phenylcoumarins were synthesized, and the structure-activity relationships were investigated by evaluating the ability of these compounds to modulate horseradish peroxidase (HRP) catalytic activity and comparing the results to four flavonoids (quercetin, myricetin, kaempferol and galangin), previously reported as HRP inhibitors. It was observed that 3-phenylcoumarins bearing a catechol group were as active as quercetin and myricetin, which also show this substituent in the B-ring. The presence of 6,2'-dihydroxy group or 6,7,3',4'-tetraacetoxy group in the 3-phenylcoumarin structure also contributed to a significant inhibitory effect on the HRP activity.

New 3-piperonylcoumarins as inhibitors of glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) from Trypanosoma cruzi.

This article describes the synthesis and inhibitory activities of a series of new 3-piperonylcoumarins, designed as inhibitors of glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) from Trypanosoma cruzi. The design was based on the structures of previously identified natural products hits. The most active synthesized derivatives contain heterocyclic rings at position 6.

Structure-activity relationships of novel inhibitors of glyceraldehyde-3-phosphate dehydrogenase.

3D QSAR studies were performed on a library of 120 GAPDH inhibitors, including a series of coumarins, flavonoids, and nucleosides. The VolSurf method was successfully used to calculate surface descriptors for protein-ligand affinity and binding site of the enzyme. PCA/PLS analyses have permitted the evaluation of the structural features crucial for potency, selectivity, and favorable pharmacokinetic properties, and are important for the design of new ligands.