A simple, highly efficient and green procedure for the condensation of o-phenylenediamines with 1, 2-dicarbonyl compounds in the presence of vitamin C, as an inexpensive organocatalyst, is described. Using this method, variety of quinoxaline derivatives with different electron releasing and electron withdrawing substituents, are produced in high to excellent yields at room temperature in ethano...

In continuation of our study the in vitro antioxidant activity of some novel quinoxaline derivatives was investigated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method with respect to ascorbic acid. To determine the antioxidant activity, a number of substituted indoxyls (3A-G), cyclic ketones (2A-G), and quinoxalines (1A-G) were synthesized by both microwave and conventional heating methods. The p...

A new enzyme which catalyzes the oxidation of the side chain of tryptophan and other indole derivatives, has been purified to apparent homogeneity from Pseudomonas and crystallized. The overall purification was about 25-fold with a yield of 4.5%. The purified enzyme was apparently homogeneous as judged by polyacrylamide gel electrophoresis. The molecular weight estimated by gel filtration was a...

A series of 3-aryl-2-quinoxaline-carbonitrile 1,4-di-N-oxide derivatives were designed, synthesized and evaluated for hypoxic and normoxic cytotoxic activity against human SMMC-7721, K562, KB, A549 and PC-3 cell lines. Many of these new compounds displayed more potent hypoxic cytotoxic activity compared with TX-402 and TPZ in the tumor cells based evaluation, which confirmed our hypothesis that...

Heterocyclic compounds have a wide range of applications, and Pictet–Spengler reaction is effectual in the synthesis heterocyclic such as quinoline isoquinoline. The present work describes an effective Pictet–Spengler-type protocol for selective quinoxaline derivatives from substituted pyrroles diverse aromatic aldehydes over tailored SnO2 nanoparticles anchored multi-walled carbon nanotubes (S...

Ever since the idea arose that melatonin might promote sleep and resynchronize circadian rhythms, many research groups have centered their efforts on obtaining new melatonin receptor ligands whose pharmacophores include an aliphatic chain of variable length united to an N-alkylamide and a methoxy group (or a bioisostere), linked to a central ring. Substitution of the indole ring found in melato...

Condensation of o-phenylenediamine with isatine in refluxing glacial acetic acid gives indolo[2,3-b] quinoxaline. This moiety further condensed with n’-(n-Halo aloxy)-3,4-dihydro carbostyril in refluxing acetonitrile using NaI,K2CO3 and TBAB as catalyst gave us desire product. Series of all six analogs are taken for their antibacterial and antipsychotic activity. The entire tested compound show...

The fundamentals of Pd-catalyzed Csp2−Csp2 Miyaura borylation, Suzuki cross-coupling, and Stille cross-coupling reactions for a variety borylated precursors based on phenothiazine (PTZ), phenoxazine (POZ), carbazole (Cz), quinoxaline (QX) units have been explored. Three palladium-based catalysts were chosen this study: Pd(PPh3)4, Pd(PPh3)2Cl2, Pd(dppf)Cl2, applying different reaction conditions...