Synthesis and Anticancer Activity of Novel Oxadiazole Functionalized Pyrazolo[3,4-b]pyridine Derivatives

A series of novel oxadiazole functionalized pyrazolo[3,4-b]pyridine derivatives (6a-n)was synthesized using 6-thiophenyl-4-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-3-amine (1) through reaction with 2-bromoethyl acetate, followed by hydrazine hydrate to afford hydrazide derivatives (5). These compounds were further treated with aromatic acids in the presence of phosphoryl chloride and obtained oxadiazole functionalized pyrazolo[3,4-b]pyridine derivatives (6a-n). All the synthesized compounds 6a-n were screened for anticancer activity against four cancer cell lines such as HeLa - cervical cancer (CCL-2); COLO 205-colon cancer (CCL-222); HepG2-liver cancer (HB-8065); MCF7-breast cancer (HTB-22). Compounds 6i, 6m and 6n were found to have more prominent anticancer activity at micromolar concentration.

Facile Metal-Free Direct Transformation of N-Allyl- and tert-Butyl-Protected Arylamines to Azacycles Using Phosphoryl Chloride and TBD

A novel synthetic approach to the preparation of N-aryl substituted azacycles from N-allyl and N-tert-butyl protected arylamines is described. In this preparation, a metal free reagent system utilizing POCl3 and TBD proved to be an important contributor for reactions of N-allyl- and tert-butyl-protected aryamines with cyclic ethers to generate the target azacycles. This protocol provides a practical approach to high yield, direct synthesis of N-aryl substituted five-membered and six-membered azacycles from N-allyl arylamines and N-tert-butyl arylamines

Use of Triphenylphosphine-Bromotrichloromethane (PPh3-BrCCl3) in the Preparation of Acylhydrazines, N-Methylamides, Anilides and N-Arylmaleimides From Carboxylic Acids

In certain countries, many of the reagents used to transform carboxylic acids to acyl halides such as phosphorus trichloride, phosphorus tribromide, phosphorus pentachloride, phosphoryl chloride, thionyl chloride and sulfuryl chloride are difficult to come by. Against this background, the authors developed the reaction system triphenylphosphine (PPh3)–bromotrichloromethane (BrCCl3) to prepare acyl halides in situ. In the following, the use of this reagent combination is joined with the reaction of the in situ prepared acyl halides with nitrogen nucleophiles, specifically with hydrazines, methylamine and anilines. The reaction is also used in an intramolecular variant by the reaction of maleanilic acids to N-arylmaleimides.

1-Isobutyl-8,9-dimethoxy-3-phenyl-5,6-dihidroimidazo[5,1-a]isoquinolin-2-ium chloride

The molecular salt, C23H26N2O2 +·Cl−, was obtained from 1-isobutyl-8,9-dimethoxy-3-phenyl-5,6-dihydroimidazo[5,1-a]isoquinoline, which was synthesized by cyclocondensation of α-benzoylamino-γ-methyl-N-[2-(3,4-dimethoxyphenyl)ethyl]valeramide in the presence of phosphoryl chloride. The tetrahydropyridine ring adopts a twist–boat conformation. In the crystal structure, centrosymmetric dimers are formed by N—H...Cl and C—H...Cl hydrogen bonds.

Design, Synthesis and Evaluation of Antioxidant Activity of Some Coumarin Derivatives

Coumarin derivatives are an important class of heterocyclic compounds, specifically 4-amino substituted coumarins with antioxidant, anticancer activities. The above observations prompted us to synthesize new coumarins with various substitutions. The starting material 4-chloro-2H-chromen-2-one was synthesized by refluxing a mixture of 4-hydroxy-2H-chromen-2-one in phosphoryl chloride. The 4-substituted amine derivatives of coumarin were synthesized by refluxing 4-chloro-2H-chromen-2- one with 4-substituted amines and anhydrous K2CO3 and methanol. All the eleven 4-substituted amine derivatives of coumarin were synthesized by replacing chloro group with different amines. These coumarin derivatives were evaluated for in vitro antioxidant activity using quercetin as standard.