One-Pot Modified Madelung Synthesis of 3-Tosyl- and 3-Cyano-1,2-disubstituted Indoles

A One-pot, two-step procedure for the synthesis of 1,2-disubstituted-3-tosyl and 1,2-disubstituted-3-cyanoindoles from the corresponding N-(o-tolyl)benzamides is reported. The developed procedure is operationally simple, does not utilize any transition metals, and provides variably substituted indoles in good yields from readily available starting materials.

Design, synthesis, and biological evaluation of 3-(1-Aryl-1H-indol-5-yl)propanoic acids as new indole-based cytosolic phospholipase A2α inhibitors

This article describes the design, synthesis, and biological evaluation of new indole-based cytosolic phospholipase A2α (cPLA2α, a group IVA phospholipase A2) inhibitors. A screening-hit compound from our library, (E)-3-{4-[(4-chlorophenyl)thio]-3-nitrophenyl}acrylic acid (5), was used to design a class of 3-(1-aryl-1H-indol-5-yl)propanoic acids as new small molecule inhibitors. The resultant structure-activity relationships studied using the isolated enzyme and by cell-based assays revealed that the 1-(p-O-substituted)phenyl, 3-phenylethyl, and 5-propanoic acid groups on the indole core are essential for good inhibitory activity against cPLA2α. Optimization of the p-substituents on the N1 phenyl group led to the discovery of 56n (ASB14780), which was shown to be a potent inhibitor of cPLA2α via enzyme assay, cell-based assay, and guinea pig and human whole-blood assays. It displayed oral efficacy toward mice tetradecanoyl phorbol acetate-induced ear edema and guinea pig ovalbumin-induced asthma models.

Structure–activity relationship studies of 3-dodecanoylindole-2-carboxylic acid inhibitors of cytosolic phospholipase A2α-mediated arachidonic acid release in intact platelets: variation of the keto moiety

Recently we found that 1-methyldodecanoylindole-2-carboxylic acid (1) and 1-[2-(4-carboxyphenoxy)ethyl]-3-dodecanoylindole-2-carboxylic acid (4) were inhibitors of the cytosolic phospholipase A2alpha (cPLA2alpha)-mediated arachidonic acid release in calcium ionophore A23187-stimulated human platelets with IC50-values of 4.8 microM (1) and 0.86 microM (4). We have now replaced the 3-acyl residue of these compounds by alkylated sulfinyl-, sulfony-, sulfinamoyl-, sulfamoyl-, carbonylamino-, or carbonylaminomethyl-substituents. Structure-activity relationship studies revealed that the pronounced cellular activity of 4 strongly depends on the presence of the 3-acyl moiety. Surprisingly, when testing 4 and its derivatives in an assay with the isolated cPLA2, none of these compounds showed an inhibitory potency at 10 microM indicating that they do not inhibit cPLA2alpha in the cells by a direct interaction with the active site of the enzyme.

Theoretical investigation on the mechanism of the CuI-catalyzed carbon-nitrogen coupling reaction of 2-iodo-selenophene with benzamide

The mechanism of the carbon-nitrogen coupling reaction of 2-iodo-selenophene with benzamide catalyzed by CuI has been investigated with density functional theory at the GGA/PW91/DND and GGA/PBE/DNP levels. The geometric configurations of the reactants, intermediates, transition states, and products were optimized and verified by means of vibration frequency calculations. A four-step mechanism was proposed for the reaction. The first step was the rate-control step. Two possible pathways in the fourth step were investigated, and the main pathway was identified by comparing their activation and dissociation energies. For comparison, the same calculations were performed to the reaction without the CuI activator. The activation barrier with CuI is 76 kJ mol(-1) smaller than that without CuI. It turns out that CuI can promote the reaction by lowering the activation energy. Our calculations reveal the crucial role of CuI in the reaction and agree well with experimental findings.

Copper-promoted carbon-nitrogen bond formation with 2-iodo-selenophene and amides

We present here carbon-nitrogen bond formation via a coupling reaction of 2-iodo-selenophene catalyzed by Cu(I) in the presence of a base and an inexpensive ligand, and establish the first route to obtaining 2-nitrogen-selenophene derivatives in good yields. We can anticipate that this reaction works well with oxazolidinones, lactams, and aliphatic and aromatic amides, as nitrogen sources, in the absence of any supplementary additives. In addition, the reaction proceeded cleanly under mild reaction conditions and was sensitive to the ratio of amide/2-iodo-selenophene, as well as the nature of the ligand, base, and solvent.