Dess–Martin Periodinane–Mediated Oxidative Aromatization of 1,3,5-Trisubstituted Pyrazolines

Oxidative Aromatization of 3,4-Dihydroquinolin-2(1H)-ones to Quinolin-2(1H)-ones Using Transition-Metal-Activated Persulfate Salts

“…With respect to the preparation of quinolin-2­(1 H )-one derivatives, one widely used strategy is the oxidative aromatization of their corresponding 3,4-dihydroquinolin-2­(1 H )-one derivatives. Although a number of methods for the oxidative aromatization of heterocyclic compounds have been developed, − they are rarely reported for the oxidative aromatization of 3,4-dihydroquinolin-2­(1 H )-one derivatives except using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). − …”

“…The frequently used oxidative methods for the aromatization of dihydroquinolin-2­(1 H )-one derivative 1 , such as oxygen, MnO 2 , Dess–Martin periodinane, PhI­(OAc) 2 , PhI­(OAc) 2 /KBr, I 2 /MeOH, I 2 /DMSO, FeCl 3 /AcOH, Pd/C/AcOH, , and TBHP/CuSO 4 , were attempted but provided unsatisfactory results with fairly low conversation rates or a complicated reaction mixture. By our further trials, easily accessible potassium persulfate (K 2 S 2 O 8 ) presented encouraging results in comparison with potassium peroxymonosulfate (Oxone), as shown in Table (entries 1 and 2).…”

A Serendipitous Synthesis: SiO2‐HNO3 Mediated Oxidative Aromatization and Regioselective Nitration of 1,3,5‐Trisubstituted‐4,5‐Dihydro‐1H‐Pyrazoles

“…Synthesis of pyrazoles is most commonly carried out by oxidation of 4,5‐dihydropyrazoles (pyrazolines), which are obtained by reaction between hydrazine and α, β‐ unsaturated carbonyls (chalcones) . Although variety of reagents such as Zr(NO 3 ) 4 , Bi(NO 3 ) 3 , Pd/C, I 2 O 5 , AgNO 3 , IBD, Pb(OAc) 4 , Co(II) and O 2 , MnO 2 , KMnO 4 , Dess‐Martin periodinane, HAuCl 4 , Fe(NO 3 ) 4 , CAN, Fe, CuCl 2 have been used as oxidising agent for this transformation. However, most of these approaches have drawbacks such as prolonged reaction time, low yield, tedious workup and use of toxic metal ions, e. g., Zr(IV), Ag(I), Pb(IV), Co(II) and Mn(VI & VII) .…”

Design and Synthesis of a BODIPY‐Tetrazole Based “Off‐On” in‐Cell Fluorescence Reporter of Hydrogen Peroxide

“…We envisioned that the conversion of the adjacent tetrazole to pyrazoline would modulate fluorescent properties of BODIPY through intramolecular PeT process. In addition, the pyrazoline can be further oxidized to pyrazole, 13 allowing the BODIPY-pyrazoline to serve as a chemical sensor for oxidative environment in cells. Herein, we report the synthesis of a series of BODIPY-tetrazoles, and characterization of their reactivity in the photoclick chemistry and their photophysical properties before and after the reaction as well as in response to hydrogen peroxide treatment.…”