Synthesis and Analgesic Activity of Some New Pyrazoles and Triazoles Bearing a 6,8-Dibromo-2-methylquinazoline Moiety

Abstract

2-(6,8-Dibromo-2-methylquinazolin-4-yloxy)-acetohydrazide (4) was prepared by the reaction of 6,8-dibromo-2-methylbenzo-[d][1,3]oxazin-4-one with formamide to afford quinazolinone 2, followed by alkylation with ethyl chloroacetate to give the ester 3. Treatment of ester 3 with hydrazine hydrate and benzaldehyde afforded 4 and styryl quinazoline 5. The hydrazide was reacted with triethyl orthoformate, acetylacetone and ethyl acetoacetate and benzaldehyde derivatives to afford the corresponding pyrazoles 6, 7, 9 and hydrazone derivatives 10a-c. Cyclization of hydrazones 10a-c with thioglycolic acid afforded the thiazole derivatives 11a-c. Reaction of the hydrazide with isothiocyanate derivatives afforded hydrazinecarbothioamide derivatives 12a-c, which cyclized to triazole-3-thiols and thiadiazoles 13a-c and 14a-c, respectively. Fusion of the hydrazide with phthalimide afforded the annelated compound 1,2,4-triazolo[3,4-a]isoindol-5-one (15). The newly synthesized compounds were characterized by their spectral (IR, 1H-, 13C-NMR) data. Selected compounds were screened for analgesic activity.

Synthesis and Bioactivity of Pyrazole Acyl Thiourea Derivatives

“…Pyrazole derivatives play an important role in the development of pesticides and medicines, which have become hot topics in recent years. Dozens of pyrazole products are available and widely used as fungicides, antiviral agents, analgesic agents, insecticides and herbicides [15][16][17]. In order to discover novel active compounds for use in agriculture, we sought to combine the active structures of thiourea and pyrazole to design and synthesize a class of novel pyrazole acyl thiourea derivatives.…”

Microwave-Assisted Synthesis, Characterization and Biological Activity of Some Pyrazole Derivatives

“…Pyrazoles are an important class of heterocyclic compounds. They exhibit a wide range of pharmacological activities like antibacterial [1][2] , antifungal [3][4] , antiviral 5 , anti-inflammatory 6 , antioxidant 7 , anti-tubercular 8 , anti-diabetic 9 , anti-tumor 10 , anesthetic 11 , analgesic 12 and insecticidal agents 13 . A microwave-assisted synthesis of chalcones (α, β-unsaturated ketones) was synthesized by base catalyzed aldol condensation of acetone or acetophenone with indol-3-aldehyde.…”

Synthesis and anti-bacterial activity of novel 1,3-pheylene-bis-N-acetyl- and N-phenylpyrazole derivatives

“…Several of pyrazole products are available and widely used as fungicides, antiviral agents, analgesic agents, insecticides and herbicides. [9][10][11] For thus, pyrazole derivatives have attracted considerable attention in the recent years for their diverse biological activities. [12][13][14][15][16][17] In this paper, the novel 1,1'-(5,5'-(1,3-phenylene)bis(3-aryl-4,5-dihydro-1H-pyrazole-5,1-diyl))diethanone (5a-e) and 1,3-bis(1-phenyl-3-(aryl)-4,5-dihydro-1H-pyrazol-5-yl)benzene (6a-e) were synthesized in good yields and evaluated the antibacterial activities of compounds (5a-e) against some human pathogenic bacteria.…”