Catalytic Conversion of 2‐Naphthol to 2‐Hydroxy‐1,4=naphthoquinone Under Mild Conditions

Abstract

2-Hydroxy-1.4-naphthaquinone (HNQ) was selectively synthesized from catalytic oxidation of 2-naphthol by molecular oxygen over tetra(4-methoxyl-pheny1)porphyrinate iron(m) chloride (TMOPPFeCl) catalyst in an alkali methanol S O~U~~O R under mild conditions. The influences of solvents, temperature, time, as well as amounts of catalysts and alkali were studied. The quantitative data show that 32.9% of 2-naphthol (0.093 m01/dm3) was catalpcally converted to HNQ with the selectivity of 100% at 323 K for 9 h over TMOPPFeCl catalyst (2.54X mol/dm3) in alkali media (30 mL of methanol containing 2.5 mol/dm' of NaOH) by flowing molecular oxygen (flowing rate of 45 d m i n ) .

Protein glycation inhibitory activities ofLawsonia inermisand its active principles

“…The remaining aqueous layer was acidified with acetic acid to pH 3, and then extracted with [29][30][31][32][33].…”

Advanced Routes in Synthesis and Reactions of Lawsone Molecules (2‐Hydroxynaphthalene‐1,4‐dione)

“…2‐Hydroxynaphthalen‐1,4‐dione (1) was synthesized by treating α‐naphthanol (3) with potassium superoxide (KO 2 ) and 18‐crown‐6 in toluene in yield 34% ; sodium hydroxide (NaOH) or potassium hydroxide (KOH), and hydrogen peroxide (H 2 O 2 ) ; oxygen and NaOH in the presence of chlorotetra(4‐methoxyphenyl)porphinatoiron (36995‐20‐7) as catalyst in propan‐2‐ol or NaOH and H 2 O 2 in the presence of (tetraphenylporphyrinato)iron(III) chloride (TPPFeCl) or 5,10,15,20‐tetra(4″‐methoxyphenyl)porhyrinatoiron(III)chloride (T( p ‐OCH 3 )PPFeCl) or chloro(tetraphenyl porphinato)iron (16456‐81‐8) as catalyst in yield 22 and 40%, respectively. While reaction of β‐naphthol ( 4 ) with KOH and oxygen in the presence of copper phthalocyanine (147‐14‐8) as catalyst at pH 2.5 ; NaOH and oxygen in the presence of benzaldehyde, p‐chlorobenzaldehyde, p‐nitrobenzaldehyde at 0°C , 36995‐20‐7 as catalyst ; or NaOH, H 2 O 2 in the presence of 16456‐81‐8 at catalyst was yielded 2‐hydroxynaphthalen‐1,4‐dione (1) .…”