Ozone-Mediated Amine Oxidation and Beyond: A Solvent-Free, Flow-Chemistry Approach.

Ozone is a powerful oxidant, most commonly used for oxidation of alkenes to carbonyls. The synthetic utility of other ozone-mediated reactions is hindered by its high reactivity and propensity to overoxidize organic molecules, including most solvents. This challenge can largely be mitigated by adsorbing both substrate and ozone onto silica gel, providing a solvent-free oxidation method.

Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols.

An intermolecular coupling of primary alcohols and organotriflates has been developed to provide ketones by the action of a Ni(0) catalyst. This oxidative transformation is proposed to occur by the union of three distinct catalytic cycles. Two competitive oxidation processes generate aldehyde in situ via hydrogen transfer oxidation or (pseudo)dehalogenation pathways.

Switchable Selectivity in the Pd-Catalyzed Alkylative Cross-Coupling of Esters.

The Pd-catalyzed cross-coupling of phenyl esters and alkyl boranes is disclosed. Two reaction modes are rendered accessible in a selective fashion by interchange of the catalyst. With a Pd-NHC system, alkyl ketones can be prepared in good yields via a Suzuki-Miyaura reaction proceeding by activation of the C(acyl)-O bond.

A Nickel-Catalyzed Carbonyl-Heck Reaction.

The use of transition-metal catalysis to enable the coupling of readily available organic molecules has greatly enhanced the ability of chemists to access complex chemical structures. In this work, an intermolecular coupling reaction that unites organotriflates and aldehydes is presented. A unique catalyst system is identified to enable this reaction, featuring a Ni precatalyst, a tridentate Triphos ligand, and a bulky amine base.

Enhanced Catalytic Activity of Aluminum Complexes for the Ring-Opening Polymerization of ε-Caprolactone.

A series of dinuclear aluminum (AlPyr) complexes bridged by two pyrazole ligands were synthesized, and their catalytic activity toward ring-opening polymerization of ε-caprolactone (CL) was investigated. Different types of the Al-N-N-Al-N-N skeletal ring were found among these AlPyr complexes. The butterfly form, LAlMe, exerted the highest catalytic activity for CL polymerization.

Palladium-Catalyzed Intramolecular Cross-Dehydrogenative Coupling: Synthesis of Fused Imidazo[1,2-]pyrimidines and Pyrazolo[1,5-]pyrimidines.

A palladium-catalyzed intramolecular dehydrogenative coupling reaction was developed for the synthesis of fused imidazo[1,2-]pyrimidines and pyrazolo[1,5-]pyrimidines. The developed protocol provides a practical approach for the synthesis of biologically important substituted pyrimidines from easily available substrates, with a broad substrate scope under mild reaction conditions.

Metal-free cycloaddition to synthesize naphtho[2,3-d][1,2,3]triazole-4,9-diones.

A metal-free domino [3 + 2] cycloaddition is reported to construct naphtho[2,3-d][1,2,3]triazole-4,9-dione derivatives and provide an alternative approach to the azide-alkyne cycloadditions. The key features are easily available starting materials, mild reaction conditions, a good atom economy, eco-friendly characteristics and a broad substrate scope with high yields.

Au(I)-catalyzed synthesis of 8-oxabicyclo[3.2.1]oct-2-enes and 9-oxabicyclo[3.3.1]nona-2,6-dienes from enynol via oxonium/Prins-type cyclization.

A sustainable and simple Au(I) catalytic system to synthesise 8-oxabicyclo[3.2.1]oct-2-enes and 9-oxabicyclo[3.

I₂-TBHP-catalyzed oxidative cross-coupling of N-sulfonyl hydrazones and isocyanides to 5-aminopyrazoles.

I2-TBHP-catalyzed oxidative cross coupling of N-sulfonyl hydrazones with isocyanides has been realized for the synthesis of 5-aminopyrazoles through formal [4 + 1] annulation via in situ azoalkene formation. Notable features are the metal/alkyne-free strategy, C-C and C-N bond formation, atom economy, catalytic I2, broad functional group tolerance, good reaction yields, shorter time, and also applicability to one-pot methodology.

An iron-catalyzed cascade approach to benzo[b]carbazole synthesis followed by 1,4-sulfonyl migration.

A simple and straightforward approach was developed to construct 5H-benzo[b]carbazole derivatives by iron catalysis in a cascade sequence. The notable features of this work include an atom-economical cascade sequence, unprecedented 1,4-sulfonyl migration, tolerance of a variety of functional groups, good yields, and an economical catalytic system.

A one-pot hypoiodite catalysed oxidative cycloetherification approach to benzoxazoles.

A practical one-pot hypoiodite catalysed oxidative cyclization approach to synthesize α-ketobenzoxazole derivatives was successfully developed. This operationally simple protocol utilizes easily-accessible starting materials and has a broad substrate scope with excellent yields.

A convenient method to construct (Z)-oxazines via 6-exo-dig iodocyclization and synthesis of indolin-3-one.

An efficient regio-, stereo- and chemo-specific synthesis of 1,3-benzoxazines via 6-exo-dig cyclization to afford the Z-isomer is reported. The structure and connectivity were confirmed unambiguously on the basis of (1)H NMR, NOESY, and ORTEP. Furthermore, DFT studies revealed that the Z-isomer was more stable than the E-isomer.

Facile, selective, and regiocontrolled synthesis of oxazolines and oxazoles mediated by ZnI2 and FeCl3.

An expedient method for a direct approach to the selective and regiocontrolled synthesis of 2-oxazolines and 2-oxazoles mediated by ZnI(2) and FeCl(3) is described. A Lewis acid promoted cyclization of acetylenic amide with various functionalities was well tolerated to give 2-oxazolines and 2-oxazoles in good to excellent yields under mild reaction conditions.

A new approach to 1,4-oxazines and 1,4-oxazepines via base-promoted exo mode cyclization of alkynyl alcohols: mechanism and DFT studies.

A new approach was developed to synthesize 1,4-oxazine and 1,4-oxazepine derivatives without solvent and metal. Regioselective cyclization occurred to afford exclusively the exo-dig product, and stereochemistry was studied by circular dichroism and specific optical rotation techniques. The Grignard reaction is a key synthetic step to produce high diastereomeric compounds via Cram's rule and was well supported by DFT calculations.

Synthesis of sulfur-sulfur bond formation from thioamides promoted by 2,3-dichloro-5,6-dicyanobenzoquinone.

A mild and efficient synthesis of sulfur-sulfur bond formation from thioformanilides with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) is described. Functionality on the aromatic ring plays a key role in the formation of a sulfur-sulfur bond.

Novel quinoline and naphthalene derivatives as potent antimycobacterial agents.

We have designed and synthesized both the quinoline and naphthalene based molecules influenced by the unique structural make-up of mefloquine and TMC207, respectively. These compounds were evaluated for their anti-mycobacterial activity against drug sensitive Mycobacterium tuberculosis H37Rv in vitro at single-dose concentration (6.25 microg/mL).

Design, synthesis and biological evaluation of novel triazole, urea and thiourea derivatives of quinoline against Mycobacterium tuberculosis.

A new series of 20 quinoline derivatives possessing triazolo, ureido and thioureido substituents have been synthesized and their antimycobacterial properties have been evaluated. Compounds 10, 22 and 24 inhibited Mycobacterium tuberculosis H37Rv up to 96%, 98% and 94% respectively, at a fixed concentration of 6.25 microg/mL.

Design, synthesis, biological evaluation and molecular modelling studies of novel quinoline derivatives against Mycobacterium tuberculosis.

We herein describe the synthesis and antimycobacterial activity of a series of 27 different derivatives of 3-benzyl-6-bromo-2-methoxy-quinolines and amides of 2-[(6-bromo-2-methoxy-quinolin-3-yl)-phenyl-methyl]-malonic acid monomethyl ester. The antimycobacterial activity of these compounds was evaluated in vitro against Mycobacterium tuberculosis H37Rv for nine consecutive days upon a fixed concentration (6.25 microg/mL) at day one in Bactec assay and compared to untreated TB cell culture as well as one with isoniazide treated counterpart, under identical experimental conditions.