Conjugated small organic molecules: synthesis and characterization of 4-arylpyrazole-decorated dibenzothiophenes

Abstract

4-Arylpyrazole-decorated dibenzothiophenes have been synthesized.

K2CO3-Mediated Intramolecular Oxa-Michael Cyclization of α,β-Unsaturated Ketoximes: Synthesis of Densely Arene-Substituted 2-Isoxazolines Bearing a Quaternary Center

“…For that we chosen Ullmann-type amination reaction with pyrazole (Scheme 12 ). 24 Gratifyingly, the dual C–N bonded product 6 was afforded in 62% yield.…”

“…13 C { 1 H} NMR (125 MHz, CDCl 3 ):  = 163.1, 138.9, 137.0, 130.4, 130.0, 129.5, 128.6, 128.5, 128.4, 117.8, 94.8. 24 A dry, screw-cap pressure tube (15 mL) equipped with a magnetic stirring bar was charged with 5,5-bis(4-bromophenyl)-3-phenyl-4,5dihydroisoxazole (2f, 50 mg, 0.109 mmol), pyrazole (5, 30 mg, 0.436 mmol), CuI (10 mg, 0.054 mmol), and Cs 2 CO 3 (284 mg, 0.87 mmol) in DMF (2.0 mL), and the mixture was stirred at 140 °C in an oil bath for 24 h. The mixture was then diluted with water and extracted with ethyl acetate, dried over Na 2 SO 4 , and concentrated under vacuum. The residue was purified by silica gel column chromatography (hexane-EtOAc, 80:20) to provide 5,5-bis(4-(1H-pyrazol-1-yl)phenyl)-3-phenyl-4,5-dihydroisoxazole (6).…”