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A one pot synthesis of 1H-benzo[g]indoles, tetrahydrobenzo[h]quinolines, and naphtho[1,2-b]azepines from 2-alkynyl benzaldehydes and cyclic amino acids is reported. The salient feature of the strategy involves formation of three new bonds (one CN and two CC bonds) by a metal-free decarboxylation/cyclization/one-carbon ring expansion sequence in one pot.

Since the very first resolution of racemic tartaric acid by Pasteur, the importance of resolution and methodology has been on a path of continuous understanding and expansion. The science and chemistry of achieving such targets has changed a lot. The advent of chromatography changed the direction by involving synthetic, semisynthetic, or naturally occurring chiral materials for a direct approach to resolution, where rapid and reversible association occurs to form diastereomers with different stabilities and partition coefficients responsible for overall enantioseparation. It has now reached a stage where the separation of excess enantiomers from nonracemic mixtures has been achieved in a totally achiral environment, which does not appear to be in line with the prevalent concepts of basic stereochemistry. Caution should be exercised when enantiomerically enriched mixtures – obtained by enantioselective synthesis – are chromatographed for purification in preparative organic synthesis.

A simple one-pot protocol for the Pd-catalyzed oxidative annulation of internal alkynes with indoles to form pyridooxindole derivatives is presented.

A simple, facile, and environmentally benign intramolecular dehydrogenative coupling of various 1,2-diarylethylenes for the synthesis of phenanthrenes in excellent yield has been described. This new methodology uses ceric ammonium nitrate (CAN) as a promoter at room temperature and has been extended to intermolecular synthesis of biaryl compounds. The electron transfer from methoxyarene to cerium leads to cationic radical formation, which further proceeds to intramolecular coupling. Preliminary mechanistic investigation by EPR spectroscopy and density functional theory calculation suggested a similar view.

Adenosine monophosphate-activated protein kinase (AMPK), a serine/threonine heterotrimeric protein kinase, is a critical regulator of cellular and whole body energy homeostasis. There are twelve known AMPK isoforms that are differentially expressed in tissues and species. Dysregulation of AMPK signaling is associated with a multitude of human pathologies. Hence isoform-selective activators of AMPK are actively being sought for the treatment of cardiovascular and metabolic diseases. The present review summarizes the status of direct AMPK activators from the patent and published literature.

A novel and efficient Cu(I)-catalyzed ligand- and base-free multipathway domino strategy has been developed for the synthesis of 2-substituted quinazolinones. The reaction utilizes 2-bromobenzamide and multiform substrates such as aldehydes, alcohols, and methyl arenes for a one-pot protocol, whereas TMSN3 is used as a nitrogen source. A wide range of substrate scope, functional group tolerance, and operational simplicity are synthetically useful features.

A versatile diastereoselective Friedel-Crafts alkylation reaction of heteroaryl systems with a cyclic enecarbamate for the preparation of 5-heteroaryl-substituted proline analogues in good yields has been developed. These heterocyclic tethered cyclic amino acid building blocks constitute important structural motifs in many biologically active molecules. The impact of the substitution on proline cis/trans isomerization was explored by carrying out solution conformational studies by NMR on 5-furanyl-substituted proline-containing peptides. Conformational analysis revealed that the peptide bond is constrained in an exclusively trans conformation.

A transition metal-free iodine catalyzed synthesis of indolizine derivatives through [3+2] cyclization of 2-pyridylesters and chalcones has been described. The method is efficient to synthesize a variety of substituted indolizines including hetero aromatic indolizines. Mechanistic studies reveal that, the reaction follows the radical pathway.

An environment friendly and efficient synthesis of primary phosphoramidates has been developed from benzyl/allyl/alkyl/propargyl halides in aqueous ethanol as a green reaction medium via in-situ formation of azide. The method is simple, metal free and high yielding at room temperature with wide substrate scope and functional group compatibility. The optimized protocol can be used for synthesis of phosphoramidate intermediates used as prodrug moieties to improve therapeutic potential of the parent drug.

Synthesis of α-oxygenated ketones from styrenes mediated by phenyliodonium diacetate in the presence of molecular oxygen and N-hydroxyphthalimide or N-hydroxybenzotriazole has been described. Addition of carbonyl oxygen at the α-position and formation of C-O bond at the β-position of styrenes was achieved under metal-free conditions. The present method is applicable for wide range of styrenes with a variety of functional groups.

An iodine/CuI mediated double oxidative C–H amination reaction has been developed for the synthesis of 2-iodo-imidazo[1,2-a]pyridines. The salient features of this methodology are mild reaction conditions and high regioselectivity. The designed compounds e.g. 2-iodo-imidazo[1,2-a]pyridines (3e) may serve as active pharmaceutical ingredients (APIs) of marketed drugs like saripidem and nicopidem. Further saripidem was synthesised by using 3e as an intermediate.

A series of aminonaphthoquinone—sulfonylamidine conjugates of type (IV) or (VII) are prepared.

Direct coupling between N-tosylhydrazones and various coupling partners such as 1,3-azoles, alkynes, and heteroatoms in the presence of Cu catalysts has turned out to be an extremely attractive route for carbon–carbon and carbon–heteroatom bond formation. Recently, both intra- and intermolecular versions, along with cascade reactions involving sequential inter- and intramolecular coupling, have made a significant impact in synthetic chemistry. Emphasis has been placed on copper as catalyst to highlight the advantages of these methods over those involving several other late-transition-metal catalysts. The limited advancements to date leave ample opportunity for further investigation in this area, which still has a long way to go in the near future. The key intermediates in these reactions arise from a carbene migratory insertion process that can be terminated in numerous ways, resulting in the formation of a diverse range of pharmaceutically important scaffolds.

Benzoic acids and benzamides are prepared by a novel type of iodine-catalyzed C(CO)-C(alkyl)bond cleavage of aryl/vinyl ketones/phenylacetylenes involving an aerobic oxidation and oxygenation process under air.

Copper-catalyzed regioselective C-3 sulfenylation of imidazo[1,2-a]pyridines using p-tosylchloride as a benign source of sulfenylating agents has been developed. On the other hand, p-tosylchloride mediated thiomethylation of imidazo[1,2-a]pyridines with dimethylsulfoxide as a source of thiomethylation under metal-free conditions was also described.

Novel, reusable, and efficient (Cd, Zn) S nanocatalysts were prepared by simple and economical chemical bath deposition using a greener approach. The as-synthesized catalysts were characterized by ...

A facile regioselective metal-free direct α-arylation of coumarins and 2-pyridones is achieved by the reaction of coumarins and 2-pyridones with phenylhydrazine in good yields. The reaction proceeds at room temperature under mild conditions using inexpensive reagents and without the need for step intensive activating groups. The methodology is operationally simple, practically viable and also allows the coupling of similar nitrogen heterocycle aza-coumarins without prerequisite N-protection.

Review: [recent developments in Cs salt promoted reactions with special focus on mechanstic aspects as well as on the recent applications in drug and organic synthesis

Starting from various iodoarenes and 4-substituted benzylamines the reaction delivers 1-arylated fluorenone derivatives resulting from a two-fold arylation sequence.

Pyrano[2,3-c]carbazoles which are biologically valuable and synthetically challenging frameworks are synthesized in high yields over five steps from commercially available resorcinol. Palladium-catalyzed arylation remains a key step in this novel strategy. The versatility of this protocol has been demonstrated by the synthesis of naturally occurring alkaloid clauraila C and 7-methoxyglycomaurin. The anti-proliferative activity of these designed compounds (5a, 5f, and 5l) has been evaluated in a cancer cell line (MOLT-4). The molecular docking study revealed that this pyrano[2,3-c]carbazole class of molecules selectively occupies the colchicine binding site of the tubulin-polymer.

An unprecedented protocol for the transformation of benzoyl azides into benzonitrile derivatives via iminophosphoranes generated in situ is described. The strategy was successfully applied to the de-novo synthesis of 2-alkenylated benzonitrile derivatives from benzoyl azides through ortho C-H activation/alkenylation followed by subsequent rearrangement. The salient features of this protocol involve incorporation of two important functionalities through cyanation and olefination in one pot under mild reaction conditions by using a less expensive Ru catalyst. The mechanism was established by isolating and characterising (using (31) P NMR) an intermediate with two ortho functionalities, iminophosphorane and olefin, under specific reaction conditions.

The reaction of substituted cyclohexenones and 2-silyloxyfurans delivers the corresponding Michael-adducts in moderate to high yields and with very high diastereo- and enantioselectivity.

A novel copper-catalyzed aerobic oxidative C(NOH)–C(alkyl) bond cleavage reaction of aryl/aralkyl/vinyl ketones for the synthesis of aromatic/acrylic acids is described. A series of ketones having aryl/aralkyl/vinyl at the one end and methyl to any higher alkyl at the other end can be selectively cleaved and converted into the corresponding acids via oxime intermediates.

CsF catalyzed direct cyanomethylation of various isatins (I) and (IV) using TMSCH2CN (II) as nucleophile is developed.

A domino cyclization of 3-((3-(2-aminophenyl)prop-2-ynylamino)methyl)but-3-en-1-ol with aldehydes has been accomplished employing 5 mol % of the Ph3PAuCl/AgSbF6/In(OTf)3 system to afford the corresponding octahydrospiro[pyran-4,4′-pyrido[3,4-b]indole] derivatives in good yields with high selectivity. This is the first report on the synthesis of spiro-β-carbolines through a multicatalytic cascade process.

A ruthenium-catalyzed ortho arylation of aromatic sulfoximines with aromatic boronic acids followed by intramolecular cyclization in the presence of a palladium catalyst, providing dibenzothiazine derivatives in two consecutive steps, is described.

Review: recent advances of fluorous metal-organic frameworks as porous solids and lighemitting properties; 10 refs.

An Ortoleva—King reaction of pyridineacetate and ketones followed by intramolecular Aldol condensation under mild reaction conditions affords indolizine-1-carboxylates.

Synthesis of (hetero)aryl pyrazolo[1,5-a]pyridines through [3 + 2] cycloaddition of N-aminopyridine with β-nitrostyrenes followed by in situ denitration and oxidation under metal-free, mild conditions are described.

Caprazamycin B was successfully synthesized via caprazol. In the present synthesis, the choices of the segment coupling conditions and protecting groups were unexpectedly narrow. Only Shiina’s protocol provided the ester linkage between the unreactive secondary hydroxyl group on the diazepanone ring system and the side chain moiety (western zone). Upon final global deprotection, hydrogenolysis conditions were compatible with substructures that are unstable under acidic and basic environments.

Arylhydrazines are used as aryl radical sources and air as oxidant in the mild procedure which does not require any prefunctionalization or N-protection of the starting quinolines.

Green chemistry has been an eye catching area of interest since the past few years. With the problem of energy crisis looming high and its constraint being particularly vulnerable on the developing economies, the need for giving alternative traditional chemistry a serious consideration as well as adequate room for development has received significant boost through the coveted efforts of multidisciplinary and interdisciplinary scientific fields. Nanoscience has been the right field in this dimension as it opens up the door to multiple opportunities through enabling a number of chemical, biochemical, and biophysical transformations in a significantly easier and reliable manner. The use of nanoparticles has made the fields of catalysis, synthesis, and enzyme immobilizations as well as molecular interactions a lot much easier, rapid and easily controllable. This review article sheds light on the popular alternative synthesis routes being employed for the synthesis of nanoparticles, the pivotal being from microbes, plants, and chemical routes via sonication, microwaving, and many others.

Copper-catalyzed synthesis of imidazo[1,5-a]pyridine-1-carboxylates through oxidative amination of C(sp3)—H bonds is described.

A copper(II)-promoted intramolecular C–H coupling reaction between indole-2 and imidazole-2 moieties has been developed for polycyclic heteroarene synthesis. The method provides direct access to biheteroaryl incorporated polycyclic frameworks, which are of huge interest in the area of functional materials and drug-discovery.

Pyrazolopyridinecarboxylates are furnished under mild conditions from commercially available pyridyl ester and benzonitriles.

Yttrium iron garnet is studied for the incorporation of cerium and thorium by a charge-coupled substitution with calcium for yttrium.

Transamidation of a series of N,N-dimethyl amides with a wide range of primary and secondary amines is accomplished environmentally friendly using sulfuric acid adsorbed on silica gel as recyclable catalytic system.

A simple one-pot synthesis is presented for the synthesis of trisubstituted imidazoles using magnetic recyclable spinel nano copper and cobalt ferrites by the condensation of benzil, different aromatic aldehydes, and ammonium acetate in ethanol.

We describe an efficient and straightforward synthesis of annulated pyridin-2(1H)-ones following condensation of acyl azides with internal alkynes via the ruthenium-catalyzed ortho C–H bond activation. The reaction in DCE proceeds via in situ generation of iminophosphoranes as directing group-coordination of Ru with N-atom-ortho cyclometallation-insertion of an alkyne into the Ru–C bond-protonation-reductive elimination in a domino sequence. The role and stability of in situ generated iminophosphorane and ruling out the possibility for the benzamide involvement was established using 1H and 31P NMR experiments.

An efficient iodine-mediated oxidative annulation of aryl acetylenes–arylethenes–aromatic ketones with 1,2-diamines for the synthesis of pyrazines and regioselective synthesis of quinoxalines is presented. A multipathway coupled domino approach has been developed for the one-pot synthesis of 1,4-diazines with high functional group compatibility.