Iridium/Graphene Nanostructured Catalyst for the N-Alkylation of Amines to Synthesize Nitrogen-containing Derivatives and Heterocyclic Compounds

A facile iridium/graphene-catalyzed methodology providing an efficient synthetic route for C-N bond formation is reported. This catalyst can directly promote the formation of C-N bonds, without pre-activation steps, and without solvents, alkalis and other additives. This protocol provides a direct N -alkylation of amines using a variety of primary and secondary alcohols with good selectivity and excellent yields. Charmingly, the use of diols resulted in intermolecular cyclization of amines, and such products are privileged structures in biologically active compounds. Two examples illustrate the advantages of this catalyst in organic synthesis: the tandem catalysis to synthesize hydroxyine, and the intermolecular cyclyzation to synthesize cyclizine. Water is the only by-product, which makes this catalytic process sustainable and environmentally friendly.

(E)-5-Benzyl-7-(3,4-dimethoxybenzylidene)-3-(3,4-dimethoxyphenyl)-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3c] Pyridine

A new pyrazolo-pyridine analogue (title compound) was synthesized in two steps. The first stage was synthesis of monoketone curcumin analogue through Claisen–Schmidt reaction. The second stage was synthesis of the title compound through intermolecular cyclization under reflux condition. The structure of the title compound has been confirmed by spectroscopic analysis including UV, FT-IR, HRMS, 1D NMR (1H-NMR, 13C-NMR, 1D-TOCSY), and 2D NMR (COSY, HSQC, HMBC). Based on the DPPH assay, the compound has moderate antioxidant activity, with an IC50 value of 194.06 ± 7.88 µg/mL (0.337 mM).

Methylation Alkynylation of Terminal Alkenes via 1,2-Alkynyl Migration using Peroxides as the Methyl Resource

The metal-free oxidative alkene methylation/alkynylation of 1,4-enyn-3-ols with an organic peroxide as the methyl resource has been developed, which provides straightforward and practical access to the challenging quaternary carbon-containing but-3-yn-1-ones. The method is reasoned to go through methylation of functional alkenes utilizing DCP as the methyling reagents and subsequent intermolecular cyclization/1,2-alkynyl migration. This reaction has an excellent functional group tolerance, broad substrate scope and exquisite selectivity.

Alkyl Carbagermatrane Enabled Synthesis of Seven-Membered Carbocycle-Fused Aromatics through Catellani Strategy

Synthesis of seven-membered carbocycle-fused aromatics was realized by Catellani reaction using terminally brominated alkyl carbagermatranes through intermolecular cyclization manner. Various functional groups were well tolerated, and this transformation was also expanded to the synthesis of carbocycles of other size. The utility of this method was demonstrated by modification of natural product derivatives and synthesis of bioactive molecules.

Brønsted Acid Catalyzed Cyclization of Inert N-Substituted Pyrroles to Benzo[f]pyrrolo[1,2-a][1,4]diazepines

Two approaches involving intramolecular and intermolecular cyclization, respectively, have been developed for the direct and practical construction of a series of important benzo[f]pyrrolo[1,2-a][1,4]azepines by using Brønsted acid catalysts. Upon catalysis by TsOH, the intramolecular dehydroxylation/ring closure of 3-hydroxy-2-[2-(1H-pyrrol-1-yl)benzyl]isoindolin-1-ones provided various racemic benzo[f]pyrrolo[1,2-a][1,4]azepines in high yields. Furthermore, enantioenriched benzo[f]pyrrolo[1,2-a][1,4]azepines were also obtained by chiral phosphoric acid catalyzed intermolecular addition of [2-(1H-pyrrol-1-yl)phenyl]methanamines to 2-formylbenzoates under mild conditions.

Synthesis, Spectral Evaluation and in Silico Studies of S-Aralkylated 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole-3-thiols: As suitable Alzheimerand#39;s disease drug candidates

Our efforts lay emphasis on synthesis of S-aralkylated 5-(4-OMeC6H5)-4-phenyl-4H-1,2,4-triazol-3-thiols like pharmacologically active candidates to counter neurodegenerative disorder; Alzheimerand#39;s disease. A synthetic strategy was instigated by esterifying 4-methoxybenzoic acid through Fisher esterificationand#39;s methodology. Hydrazinolysis of corresponding ester was performed under reflux with methanolic hydrated hydrazine to afford 4-methoxybenzohydrazide (I) which refluxing with phenyl isothiocyanate (II) in MeOH to yield a reactive intermediate (III). The later underwent base-catalyzed intermolecular cyclization to furnish 5-(4-OMeC6H5)-4H-1,2,4-triazol-3-thiol (IV). Ultimately, IV was aralkylated at thiol position with aralkyl halides V(a-l) in polar aprotic solvent and catalytic amounts of LiH to provide S-aralkylated 5-(4- OMeC6H5)-4-phenyl-4H-1,2,4-triazol-3-thiols VI(a-l). Modern spectral analysis data explicitly established all the substitutions on nucleophilic S-atom of parent 1,2,4-triazol-3-thiol ring. Effective anti-cholinesterase potential depicted in 3-(phenylpropylthio)-5-(4-OMeC6H5)-4-phenyl-4H-1,2,4-triazole; VIc (IC50; 3.26and#177;0.35 μM) against acetyl cholinesterase; AChE and 3-(phenethylthio)-5-(4-OMeC6H5)-4-phenyl-4H-1,2,4-triazole; VIb (IC50; 8.52and#177;0.54 μM) against butyrylcholinesterase; BChE enzyme as compared to standard Eserine for both enzymes (IC50; 0.04and#177;0.01 μM). Molecular modelling analyses had been conducted to recognize the interconnection of these compounds with enzymes that suggested key interactions (Docking is made to untie the active binding sites). Anti-proliferative activity results showed VIg and VIj with -Cl groups on benzylic ring as promising candidates with HCT-116 cell viability of 14.83 % and 3.09 % respectively.