A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C-C bond cleavage.

An efficient, simple, and metal-free synthetic approach for the N- and O-benzoylation of various amines/benzyl alcohols with pyridinium salts of phenacyl bromides is demonstrated to generate the corresponding amides and esters. This protocol facilitates the oxidative cleavage of a C-C bond followed by formation of a new C-N/C-O bond in the presence of K2CO3. Various pyridinium salts of phenacyl bromides can be readily transformed into a variety of amides and esters which is an alternative method for the conventional amidation and esterification in organic synthesis. High functional group tolerance, broad substrate scope and operational simplicity are the prominent advantages of the current protocol.

Regioselective Ring Expansion of Isatins with In Situ Generated α-Aryldiazomethanes: Direct Access to Viridicatin Alkaloids.

A novel efficient one-pot regioselective ring-expansion reaction of isatins with in situ generated α-aryl/heteroaryldiazomethanes for the construction of viridicatin alkaloids has been described under metal-free conditions. The utility of this protocol is further demonstrated in the synthesis of naturally occurring viridicatin, viridicatol, and substituted 3- O-methyl viridicatin and their scale up.

Glycogen synthase kinase-3 and its inhibitors: Potential target for various therapeutic conditions.

Glycogen Synthase Kinase-3 (GSK-3) is a serine/threonine kinase which is ubiquitously expressed and is regarded as a regulator for various cellular events and signalling pathways. It exists in two isoforms, GSK-3α and GSK-3ß and can phosphorylate a wide range of substrates. Aberrancy in the GSK-3 activity can lead to various diseases like Alzheimer's, diabetes, cancer, neurodegeneration etc., rendering it an attractive target to develop potent and specific inhibitors. The present review focuses on the recent developments in the area of GSK-3 inhibitors and also enlightens its therapeutic applicability in various disease conditions.

Silver catalyzed domino aza-annulation/Diels-Alder cyclization of 2-ene-yne anilines: a facile one-pot access to carbazole, dihydrocarbazole and tetrahydrocarbazole frameworks.

An unprecedented and efficient AgSbF6-catalyzed domino aza-annulation/Diels-Alder/aromatization cascade for the construction of carbazoles, dihydrocarbazoles and tetrahydrocarbazoles was achieved using 2-(but-3-en-1-yn-1-yl) anilines in the presence of suitable dienophiles. The reaction proceeds via the in situ generation of 2-vinyl indoles and their subsequent trapping by various dienophiles with concomitant aromatization. A series of symmetrical, unsymmetrical and base sensitive dienophiles provide the corresponding carbazoles under mild conditions in excellent yields with high regioselectivity.