Pd-catalysed intramolecular transformations of indolylbenzenesulfonamides: -sulfonamido-bi(hetero)aryls C2-arylation and polycyclic sultams C3 arylation.

Palladium-catalysed and base-dependent intra-molecular -substitution and cyclisation strategies involving -indolyl-substituted aryl-sulfonamides for the rapid construction of 2-aryl indole and indole-fused six-membered sultams are described. The Pd(OAc)/PhP/EtN combination delivers indolyl C2 arylated motifs C(2)-N bond cleavage followed by C-C bond formation. In sharp contrast to this, the Pd(OAc)/PhP/KCO combination induced intramolecular-Heck cross-coupling affords polycyclic sultams exclusively.

Cu(I)-Catalyzed Ligand-Free Tandem One-Pot or Sequential Annulation via Knoevenagel Intermediates: An Entry into Multifunctional Naphthalenes, Phenanthrenes, Quinolines, and Benzo[]carbazoles.

A simple but efficient one-pot or sequential copper-catalyzed protocol using 2-bromoaldehydes and active methylene group containing substrates that affords multifunctional naphthalenes, phenanthrenes, quinolines, and benzo[]carbazoles via Knoevenagel condensation, C-arylation, and decarboxylation, followed by aromatization, is developed. The reaction utilizes the potential of Knoevenagel intermediates and does not require any ancillary ligand. The phenanthrene products thus obtained show moderate fluorescence activity.

InCl mediated heteroarylation of indoles and their derivatization via CH activation strategy: Discovery of 2-(1H-indol-3-yl)-quinoxaline derivatives as a new class of PDE4B selective inhibitors for arthritis and/or multiple sclerosis.

A new class of PDE4 inhibitors were designed and synthesized via the InCl mediated heteroarylation of indoles and their further derivatization through the Pd(II)-catalyzed CH activation strategy. This effort allowed us to discover a series of 2-(1H-indol-3-yl)-quinoxaline based inhibitors possessing PDE4B selectivity over PDE4D and PDE4C. One of these compounds i.

Use of AlCl in Friedel Crafts arylation type reactions and beyond: an overview on the development of unique methodologies leading to N-heteroarenes.

As a privileged class of heterocyclic compounds N-heteroarenes have found enormous applications in many areas including medicinal/pharmaceutical chemistry and drug discovery. Consequently, a wide variety of methods have been reported for their synthesis. While not free from their own limitations the AlCl mediated methods appeared to have some particular advantages in preparing a number of useful N-heteroarenes.

Ligand-free MCR for linking quinoxaline framework with a benzimidazole nucleus: a new strategy for the identification of novel hybrid molecules as potential inducers of apoptosis.

We report a true MCR involving the reaction of N-(prop-2-ynyl)quinoxalin-2-amine derivatives with 2-iodoanilines and tosyl azide in the presence of 10 mol% of CuI and Et3N in DMSO to afford the pre-designed hybrid molecules containing quinoxaline framework linked with a benzimidazole nucleus. The MCR proceeds in the absence of any ligand and/or lateral addition of the catalyst/base affording products within 30 min in good yields, some of which showed encouraging apoptosis inducing properties in zebrafish.

Vinylic amino group activation: a new and general strategy leading to functionalized fused heteroaromatics.

A conceptually new and general strategy has been developed for the construction of a benzimidazole or a benzoxazole ring fused with isoquinolinone affording a diverse and unique class of small molecules as potential and novel inhibitors of PDE4.

Facile assembly of two 6-membered fused N-heterocyclic rings: a rapid access to novel small molecules via Cu-mediated reaction.

A rapid, versatile and one-pot Cu-mediated domino reaction has been developed for facile assembly of two six membered fused N-heterocyclic rings leading to novel small molecules as potential inhibitors of PDE4.