(E)-3-(2-Alkyl-10H-phenothiazin-3-yl)-1-arylprop-2-en-1-ones: Preparative, IR, NMR and DFT study on their substituent-dependent reactivity in hydrazinolysis and sonication-assisted oxidation with copper(II)nitrate.
A series of novel 3(5)-aryl/ferrocenyl-5(3)-phenothiazinylpyrazoles and pyrazolines were obtained by substituent-dependent regioselective condensation of the corresponding (E)-3-(2-alkyl-10H-phenothiazin-3-yl)-1-aryl/ferrocenylprop-2-en-1-one with hydrazine or methylhydrazine in acetic acid. The different propensity of the primary formed beta-hydrazino adducts to undergo competitive retro-Mannich reaction was interpreted in terms of tautomerisation equilibrium constants calculated by DFT using a solvent model. The regioselectivity of the cyclisation reactions with methylhydrazine and the substituent-dependent redox properties of pyrazolines were also rationalized by comparative DFT calculations performed for simplified model molecules. On the effect of ultrasound-promoted oxidation with copper(II)nitrate phenothiazine-containing pyrazolines, enones and oxo-compounds were selectively transformed into sulfoxides. Only one sulfoxide enone was partially converted into an oxirane derivative. The structure of the novel products was determined by IR and NMR spectroscopy including COSY, HSQC, HMBC and DNOE measurements.
Găină
Luiza
L
Department of Organic Chemistry, Babeş-Bolyai University, str. Arany János 11, RO-40028, Cluj-Napoca, Romania.
Csámpai
Antal
A
Túrós
György
G
Lovász
Tamás
T
Zsoldos-Mády
Virág
V
Silberg
Ioan A
IA
Sohár
Pál
P
D003300:Copper / Q000737:chemistry*; D003500:Cyclization; D006834:Hydrazines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D009566:Nitrates / Q000737:chemistry*; D010084:Oxidation-Reduction; D010640:Phenothiazines / Q000138:chemical synthesis / Q000737:chemistry*; D047069:Pyrazolones / Q000737:chemistry; D013010:Sonication; D013055:Spectrophotometry, Infrared
D006834:Hydrazines; D009566:Nitrates; D010640:Phenothiazines; D047069:Pyrazolones; D003300:Copper; C516433:copper(II) nitrate