Synthesis of Some New Fused Pyrazole Derivatives Bearing Indole Moiety as Antioxidant Agents

Abstract

3‐(1H‐Indol‐3‐yl)‐1H‐pyrazol‐5‐amine 3 was prepared in a quantitative yield by heating 3‐(1H‐indol‐3‐yl)‐3‐oxopropanenitrile 2 in dry ethanol with hydrazine hydrate, and utilized as key intermediate for the synthesis of some new pyrazolo[1,5‐a]pyrimidines and pyrazolo[5,1‐c]triazines. Structures of the newly synthesized compounds were established by elemental analysis and spectral data and evaluated as antioxidant agents. Most of the tested compounds belonging to the pyrazolo[1,5‐a]pyrimidine series exhibited better activities than members of the pyrazolotriazine one.

An Efficient and Facile Synthesis of Functionalized Indole‐3‐yl Pyrazole Derivatives Starting from 3‐Cyanoacetylindole

“…Finally, in view of the growing biological importance of imidazo [1,2-b]pyrazole derivatives [27,28], it was of interest to turn our attention to study the regioselectivity of the cyclization reactions of the aminopyrazole (4) with chloroacetyl chloride and phenacyl bromide with the aim of preparing functionalized imidazo [1,2-b]pyrazoles. So, the reaction of (4) with each of chloroacetyl chloride in dioxane or phenacyl bromide in glacial acetic acid under reflux yielded the corresponding imidazo[1,2-b]pyrazole derivatives (13) and (14), respectively. Although the endocyclic imino group in (4) is the most nucleophilic center [29][30][31], it is the most sterically hindered site [32].…”

“…We have recently reviewed the methods of preparation and the chemical reactivity of 3‐cyanoacetylindole as building block for the synthesis of polyfunctionalized 3‐substituted indole derivatives with pharmacological interest . As a consequence of our recent work aimed at synthesis of new heterocyclic systems with remarkable biological importance , it was planned to present an efficient regioselective synthesis of some novel biologically active heterocycles such as pyrazolo[1,5‐ a ]pyrimidines, imidazo[1,2‐ b ]pyrazoles, pyrazolo[1,5‐ a ][1,3]diazepine and pyrazolo[1,5‐ c ][1,3,5]thiadiazine bearing indole ring system, which have not been reported hitherto. The results of screening of their biological activity will be reported in due course.…”

Convenient synthesis of novel sulfonamide derivatives as promising anticancer agents

“…Besides, the 1 H-NMR spectrum exhibited downfield shifted singlet signal of COOH proton at δ 10.89 ppm. Treatment of 19 with an excess of thionyl chloride gave the corresponding acid chloride 20, [41] which then readily reacted with 2-aminobenzoic acid in dry pyridine to afford N-(4-(4-oxo-4H-3,-1-benzoxazin-2-yl)phenyl)benzenesulfonamide (21). A strong lactone absorption band appeared in the IR spectrum of benzoxazinone 21 at 1764 cm −1 .…”

“…[8,17,18] Some noteworthy examples of biologically active drugs containing sulfonamide are shown in Figure 1. [3,8,19] In the light of the immense biological significance of sulfonamides and in the continuity of our research projects on the synthesis of biologically effective compounds, [20][21][22][23] we have undertaken in this study the synthesis of novel sulfonamide derivatives from the readily accessible N-(4-acetylphenyl)benzenesulfonamide (1) [24,25] to evaluate their cytotoxic activities in vitro.…”

Green approach for the synthesis of 3‐methyl‐1‐phenyl‐4‐((2‐phenyl‐1H‐indol 3‐yl)methylene)‐1H‐pyrazole‐5(4H)‐ones and their DNA Cleavage, antioxidant, and antimicrobial activities

“…Pyrazole is an important pharmacophore, which exhibits a wide spectrum of biological activities, such as antitumor, antidepressant, antidiabetic, antiamoebic, and COX‐2 inhibitor . Incorporation of pyrazoline in indole framework enhances pharmacological importance, according to the review of literature indole derivatives bearing pyrazoline moiety possess diverse biological activities like antitumor, antioxidant, anticancer, antimicrobial, and anti‐inflammatory…”