Oxidation of 4-methoxyanilines to 1,4-benzoquinones using ceric ammonium nitrate (CAN)

Abstract

Treatment of substituted 4-methoxyanilines with ceric ammonium nitrate in a 1:1 mixture of water and acetonitrile resulted in formation of 1,4-benzoquinones in acceptable yields.

Synthesis and Spectral Analysis of 3,4,5‐trichloro‐6‐(dibenzo[d,f][1,3]diazepin‐5‐yl)‐[1,2]‐benzoquinones

“…Elemental analyses were obtained on a Carlo Erba 1106 CHN analyzer, while the IR (potassium bromide) were recorded on a Schimadzu 470 spectrophotometer. The 300 MHz 1 H and 75 MHz 13 C nmr spectra were observed on a Bruker WM 300 instrument with TMS as the internal standard using dimethylsulfoxide-d 6 General procedure for preparation of 3a-d and 4a,b…”

“…For example 13 C NMR spectrum of 3b showed 21 signals, six signals for aromatic CH, three signals at higher field identified as methyl, methylene and methoxy carbon atoms and fourteen quaternary carbon atoms, three of them resonating at downfield at δ = 185.15, 185.97 ppm for the two carbonyl carbon atoms. 13 C DEPT spectrum of 3b showed a signal with a negative amplitude at 27.44 ppm was assigned to the exo methylene carbon atom, for more details see the experimental section. 1 H NMR spectrum of 3b showed an OH proton and only six aromatic protons and only one methoxy group indicating a release of methyl group as CH 3 Cl.…”

“…so it is not surprising to behave as an electrophile as well as a dehydrogenating agent. Recently it was reported that treatment of substituted 4-methoxyanilines with ceric ammonium nitrate CAN in acetonitrile resulted in the formation of 1,4-benzoquinones in acceptable yields 13 . But in this present investigation the o-chloranil is not strong oxdizing agent like CAN, it can be considered as a mild oxdiznig agent 14 .…”

Elucidation of degradation mechanism of reactive blue 171 dye by ceric ammonium nitrate

“…Among the lanthanides, cerium has a unique ability to exist in two stable states +3 and +4 with configurations [Xe]4f 1 and [Xe]4f 0 , respectively. Cerium (IV) salts are relatively less toxic in comparison with other oxidizing compounds, with Ceric ammonium nitrate (CAN) having main advantage of higher solubility in water (1,410 g/L at 25°C) over other cerium (IV) reagents . CAN is an orange colored inorganic compound with the formula of (NH 4 ) 2 Ce(NO 3 ) 6 and is a known oxidizing and nitrating agent in organic synthesis .…”

Benzothiazines in organic synthesis. An approach to floresolide B

“…This compound, unlike its congener 16 , could be oxidized to quinone 23 using ceric ammonium nitrate (CAN) in good yield. 8 Reduction of the quinone with dithionite and protection of the resulting hydroquinone afforded 5 in excellent yield. Its identity was confirmed by a comparison of 1 H and 13 C spectra with those of authentic racemic material.…”