Formation of 4-Halo-4-nitrocyclohexa-2,5-dienones on nitration of p-halophenols and p-halophenyl acetates

Clewley, R. G.; Cross, Gordon G.; Fischer, Alfred; Henderson, George N.

doi:10.1016/0040-4020(89)80128-0

Cited by 16 publications

(11 citation statements)

References 15 publications

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“…2,4-Dichloro-6-nitrophenol (3k) [31] : Recrystallised from ethanol to yield an orange solid. Yield: 49%, g. 1 H NMR (400 MHz; CDCl 3 ) 10.96 (1H, s, O H ), 7.92 (1H, s, Aryl- H ), 7.62 (1H, s, Aryl- H ), 13 C NMR (100 MHz, CDCl 3 ) 150.1, 137.7, 125.7, 124.5, 123.1.…”

Section: Methodsmentioning

confidence: 99%

Copper-Mediated Nitrosation: 2-Nitrosophenolato Complexes and Their Use in the Synthesis of Heterocycles

2019

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A simple protocol yielding ortho-substituted nitrosophenols from phenols is demonstrated, in the form of copper(II) bis(nitrosophenolato) complexes. The developed methodology was applied to a range of substrates, confirming the role of the copper in both the formation and protection of the challenging 1, 2-substitution pattern. Using polymer supported thiourea, the Cu could be stripped from the complexes and thus enabled the isolation or identification of the uncoordinated ligands and their decomposition products, in yields generally low in line with the intrinsic high reactivity of 2-nitrosophenols. The product complexes are useful intermediates as demonstrated in revisiting a formal [4 + 2] cycloaddition with dimethylacetylene dicarboxylate to synthesise bicyclic products in variable yields, revealing the product has a novel structure different from those previously reported in the literature.

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Section: Methodsmentioning

confidence: 99%

Copper-Mediated Nitrosation: 2-Nitrosophenolato Complexes and Their Use in the Synthesis of Heterocycles

2019

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“…5-Fluoro-2-(4-methyl-1-piperazinyl)benzoxazole (6f): obtained as a white needle, 207 mg, 70% yield from 4-fluoro-2-nitrophenol, mp 116−117 °C (ether−hexane). NMR (CDCl 3 ) δ: 2.35 (3H, s), 2.52 (4H, t, J = 5 Hz), 3.72 (4H, t, J = 5 Hz), 6.71 (1H, dt, J = 2, 9 Hz), 7.04 (1H, dd, J = 2, 9 Hz), 7.14 (1H, dd, J = 4, 9 Hz).…”

Section: Methodsmentioning

confidence: 99%

Benzoxazole Derivatives as Novel 5-HT₃Receptor Partial Agonists in the Gut

et al. 1998

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A series of benzoxazoles with a nitrogen-containing heterocyclic substituent at the 2-position was prepared and evaluated for 5-HT3 partial agonist activity on isolated guinea pig ileum. The nature of the substituent at the 5-position of the benzoxazole ring affected the potency for the 5-HT3 receptor, and the 5-chloro derivatives showed increased potency and lowered intrinsic activity. 5-Chloro-7-methyl-2-(4-methyl-1-homopiperazinyl)benzoxazole (6v) exhibited a high binding affinity in the same range as that of the 5-HT3 antagonist granisetron, and its intrinsic activity was 12% of that of 5-HT. Compound 6v inhibited 5-HT-evoked diarrhea but did not prolong the transition time of glass beads in the normal distal colon even at a dose of 100 times the ED50 for diarrhea inhibition in mice. Compounds of this type are expected to be effective for the treatment of irritable bowel syndrome without the side effect of constipation.

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“…• generates 4-chloro-2-nitrocyclohexa-2,5-dienone ( Clewley et al, 1989 ). Such dienone is known to be unstable and undergoes rearrangement with the assistance of a H 2 O molecule, resulting in the formation of nitro-derivative ( Ji et al, 2017 ;Chen et al, 2020 ) (Scheme 3 of Fig.…”

Section: Intermediate Products and Transformation Pathwaysmentioning

confidence: 99%

Trace level nitrite sensitized photolysis of the antimicrobial agents parachlormetaxylenol and chlorophene in water

Qin

et al. 2021

Water Research

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Nitrite (NO 2− )-sensitized photolysis plays an important role in the attenuation of effluent-derived trace organic contaminants (e.g., anilines, phenolic compounds, etc.) in surface waters. However, the kinetics, mechanisms, and influencing factors of photolysis of many emerging contaminants sensitized by NO 2 − still remain largely unknown. Herein, we report that NO 2 − -sensitized photolysis of the antimicrobial agents parachlormetaxylenol (PCMX) and chlorophene (CP) in aqueous solution under ultraviolet 365 nm (UV 365 ) radiation. A nonlinear increase in photolysis rate constants of PCMX and CP was observed with increasing NO 2 − concentration. Radical quenching studies and kinetic modeling revealed that hydroxyl radical (HO •) and nitrogen dioxide radicals (NO 2• ) contributed dominantly to the removal of PCMX and CP. Solid phase extraction (SPE) combined with high resolution-mass spectrometry (HR-MS) analysis identified a series of intermediate products including hydroxylated, nitrated, nitrosated, and dimerized derivatives. Experiments with isotopically labelled nitrite ( 15 NO 2 − ) showed that the nitro-and nitroso-substituents of intermediate products were derived from the nitrite nitrogen. Based on the identified products and theoretical computations, the mechanisms and pathways of NO 2 − -sensitized photolysis of PCMX and CP are elucidated. Deoxygenation partially inhibited the formation of 4-chloro-3,5dimethyl-2-nitrophenol (nitro-PCMX) while the presence of HO • scavenger such as isopropanol ( i -PrOH) suppressed the further transformation of nitro-PCMX. The presence of Mississippi River natural organic matter (MRNOM) inhibited the removal of PCMX and CP, likely due to light screening and radical quenching. However, appreciable degradation of PCMX and CP was still observed in wastewater and wetland water matrices. Results of this study shed some light on the transformation and fate of PCMX and CP in NO 2 − -rich wastewater effluents or effluent-impacted surface waters under solar radiation.

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Formation of 4-Halo-4-nitrocyclohexa-2,5-dienones on nitration of p-halophenols and p-halophenyl acetates

Cited by 16 publications

References 15 publications

Copper-Mediated Nitrosation: 2-Nitrosophenolato Complexes and Their Use in the Synthesis of Heterocycles

Copper-Mediated Nitrosation: 2-Nitrosophenolato Complexes and Their Use in the Synthesis of Heterocycles

Benzoxazole Derivatives as Novel 5-HT₃Receptor Partial Agonists in the Gut

Trace level nitrite sensitized photolysis of the antimicrobial agents parachlormetaxylenol and chlorophene in water

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Formation of 4-Halo-4-nitrocyclohexa-2,5-dienones on nitration of p-halophenols and p-halophenyl acetates

Cited by 16 publications

References 15 publications

Copper-Mediated Nitrosation: 2-Nitrosophenolato Complexes and Their Use in the Synthesis of Heterocycles

Copper-Mediated Nitrosation: 2-Nitrosophenolato Complexes and Their Use in the Synthesis of Heterocycles

Benzoxazole Derivatives as Novel 5-HT3Receptor Partial Agonists in the Gut

Trace level nitrite sensitized photolysis of the antimicrobial agents parachlormetaxylenol and chlorophene in water

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Benzoxazole Derivatives as Novel 5-HT₃Receptor Partial Agonists in the Gut