Aerobic Copper Catalytic Oxidation of Methylene and Arylidenebisnaphthols: A Green and Efficient Synthesis of Spironaphthalenones

Abstract

Methylene and arylidene bisnaphthols can be converted into 4,5,2’,3’‐dibenzo‐3‐grisa‐2’,4’‐dien‐6’‐ones under catalytic conditions in the presence of copper(II)‐tetramethylethylenediamine [CuCl(OH)(TMEDA)]2. The reaction simply proceeds under air at room temperature and the control of stereoselectivity is total, affording the only (RR+SS) diastereoisomer.

Catalytic and Multicomponent Reactions for Green Synthesis of Some Pyrazolone Compounds and Evaluation as Antimicrobial Agents

“…Initially, when the procedure was carried out in the absence of a catalyst, the products were produced with poor yields after 2–3 h. Also, addition of 0.2 mmol imidazole resulted in low product yields, and increasing the catalytic amount of imidazole to 0.5 mmol provided 4-dicyanomethylene-2-pyrazoline-5-one derivatives ( 14a–d ) in good yields; however, increasing the catalytic amount further did not boost product yields. The solvent effect on the preparation of ( 14a–d ) is initially investigated via the treatment of 2-pyrazoline-5-one derivatives ( 6a–d ), TCE ( 7 ), and 0.5 mmol imidazole in various solvents such as water, acetonitrile, ethanol, methanol, tetrahydrofuran, and dioxane. − However, water afforded higher yields than their other counterparts. 14a–d were elucidated via comparison with reported data by conventionally known methods. ,,, …”

“…Moreover, dihydrospiropyrazoleoxirane derivatives ( 18 ) and ( 20 ) were synthesized by oxidation of 14b using alkaline hydrogen peroxide (Scheme ). The influence of temperature and the solvent on the synthesis of 18 and 20 was investigated by the reaction between 4-dicyanomethylene-2-pyrazoline-5-one derivatives ( 14b ), hydrogen peroxide, and a few drops of 10% potassium hydroxide solution in different solvents such as n -hexane, cyclohexane, benzene, 1,4-dioxane, tetrahydrofuran, t -butyl alcohol, ethanol, and acetonitrile. − However, acetonitrile provided higher yields than its other counterparts (Table ).…”

Green synthetic investigation and spectral characterization of some spiro pyrazolidine‐based heterocycles with potential biological activity

“…The pair of diastereomer 5c were separated using the HPLC technique qualitatively. The mechanism of epoxidation includes a concerted reaction mechanism characterized by a four‐part, cyclic transition state, as a result, the electropositive, oxygen atom ended up in the cyclopropane ring, and the COO 2 H group becomes COOH . MMPP has electropositive oxygen atom on carboxylic group.…”

“…Moreover, the green chemistry approach was employed to investigate the effect of solvent polarity in the epoxidation of chalcone derivatives 4a‐h by using magnesium monoperoxyphthalate hexahydrate (MMPP) as a versatile oxidizing agent. The oxidation in presence of protic solvent (ethanol) was better in yield than aprotic solvent (THF) (Scheme ) . The chemical reactivity of the oxidizing agent (MMPP) towards chalcone derivatives 4a‐h in THF due to their polarity and weak THF/water hydrogen bond .…”

On the green catalytic synthesis of purpurogallin

“…18 One of the most active complexes is the copper complex with tetramethylethylene diamine 19 [CuCl (OH)TMEDA] 2 .We have used this complex in the aerobic coupling of naphthol to binaphthol 20 or spiro derivatives. 21 PEI-copper in the laboratory has similar properties in many oxidations of phenols. 22 We tested the effectiveness of the two [CuCl(OH)TMEDA] 2 and Cu(I)/PEI catalysts in the synthesis of purpurogallin by aerobic oxidation of pyrogallol.…”