Reduction of quinones and quinonemonosulfonimides with N,N-diethylhydroxylamine

Fujita, Shinsaku; Sano, Kazuya

doi:10.1021/jo01329a012

Cited by 28 publications

(14 citation statements)

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“…The formation of products 2a , 2b , 2c , 2d , 2e and 2h can be rationalized by initial formation of the hydrazono or oxime derivative at acetyl carbonyl group, followed by nucleophilic substitution of substituted‐N or ‐O at C‐3 of 1,4‐naphthoquinone moiety; this reaction pathway is supported by the fact that nucleophilic substitution at C‐3 in naphthoquinones by amino groups is a known reaction . In general, the reaction is very complex, and the reduced naphthohydroquinone derivatives 3 and 4 , together with the C‐3 NXR substituted 2‐acetyl‐1,4‐naphthoquinone 5 are also detected (Figure ) .…”

Section: Resultsmentioning

confidence: 98%

The Synthesis of Some Fused Pyrazolo‐1,4‐Naphthoquinones

Molinari

Oliva

Arismendi

et al. 2014

Journal of Heterocyclic Chem

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Section: Resultsmentioning

confidence: 98%

The Synthesis of Some Fused Pyrazolo‐1,4‐Naphthoquinones

Molinari

Oliva

Arismendi

et al. 2014

Journal of Heterocyclic Chem

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“…119–121 °C; lit m.p. 120–121 °C; IR 3519, 3264, 1502, 1437, 1365, 1192, 821, 797 cm –1 ; 1 H NMR (500 MHz, CDCl 3 ) δ 2.43(3 H, s), 4.88(2 H, s(br)), 6.75(2 H, m), 6.87(1 H, m), 7.30(2 H, d, J = 8 Hz), 7.35(2 H, d, J = 8 Hz); 13 C NMR (125.8 MHz, CDCl 3 ) δ 21.1, 115.5, 116.5, 116.6, 128.7, 128.8, 129.9, 133.8, 137.8, 146.4, 149.2.…”

Section: Methodsmentioning

confidence: 99%

Reversible formation of aryloxenium ions from the corresponding quinols under acidic conditions

Chakraborty

Brzozowski

Novák

2012

J of Physical Organic Chem

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are products of the hydration of O-aryloxenium ions, 2, and N-arylnitrenium ions, 3, and they are being investigated for medical uses. Under acidic conditions (pH 1-3) kinetics and products of Brtrapping demonstrate that 1a, 4-phenyl-4-hydroxy-2,5-cyclohexadienone, and 1b, 4-p-tolyl-4-hydroxy-2,5-cyclohexadienone, generate the corresponding oxenium ions 2a and 2b, respectively, as steady-state intermediates. Formation and trapping of the oxenium ions occurs in competition with the acid catalyzed dienone-phenol rearrangement. Because oxenium ion formation is reversible, the ion can only be detected by trapping with a nucleophile. Bris an efficient trap under acidic conditions because, unlike N 3 -, it is not protonated under those conditions. Attempts to detect the oxenium ions 2a and 2b at pH 4.6 and 7.1 with N 3 were unsuccessful indicating that oxenium ion formation only occurs under acidic conditions. The oxenium ion 2c could not be detected under acidic conditions from the quinol 1c, 4-(benzothiazol-2-yl)-4-hydroxy-2,5-cyclohexadienone, by Brtrapping methods, even though this ion can be detected during hydrolysis of the corresponding ester, 4c. Although the benzothiazol-2-yl group is a resonance electron donor that is capable of stabilizing an O-aryloxenium ion, it is also a strong inductive electron withdrawing group that hinders the formation of 2c from 1c by decreasing the extent of protonation of 1c to generate 1cH + and by destabilizing the transition state for ionization of 1cH + . Generation of an oxenium ion from the corresponding quinol is feasible under acidic conditions as long as the 4-substituent of the quinol is both a resonance and inductive electron donor.Derived constants obtained from non-linear least-squares fits to the appropriate equation. Scheme 3. Protonation of N in 1c leads to a unique hydrolysis OXENIUM ION CHEMISTRY

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“…The chemical reduction of quinone calixarenes has been reported using aqueous sodium dithionite, 18 and sodium borohydride. 19 Here we chose to use N,N-diethylhydroxylamine (DEH), which has been reported to reduced quinones, 16 to reduce Q to the dihydroquinone QR, to simplify the isolation of the product. Changes in the NMR spectra of the product were observed, and HRMS confirmed that the target had been isolated.…”

Section: Ligand Synthesis and Characterizationmentioning

confidence: 99%

Lanthanoid Coordination with a Tetrazole-Substituted Calix[4]diquinone and Calix[4]dihydroquinone

Cameron¹,

Rajagopalam²,

Galán³

et al. 2019

Preprint

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<div><div><div><p>The tetrazole-functionalised calixdiquinone 5,17-di-tert-butyl-26,28-bis-(tetrazol-5-ylmethoxy)- calix[4]-25,27-diquinone Q was synthesised by chemical oxidation of the bis-tetrazole calix[4]arene precursor using PbO2/HClO4. The single crystal X-ray structure determination of Q confirmed the structure and showed binding of a water molecule in the solid state. Chemical reduction of Q to the dihydroquinone QR was achieved using N,N-diethylhydroxylamine. Comparison of the solution phase photophysical properties of Q or QR in the presence of terbium ions showed significant excitation only with QR, suggesting redox switching of the photophysical response may be possible with this or similar receptors.</p></div></div></div>

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Reduction of quinones and quinonemonosulfonimides with N,N-diethylhydroxylamine

Cited by 28 publications

References 0 publications

The Synthesis of Some Fused Pyrazolo‐1,4‐Naphthoquinones

The Synthesis of Some Fused Pyrazolo‐1,4‐Naphthoquinones

Reversible formation of aryloxenium ions from the corresponding quinols under acidic conditions

Lanthanoid Coordination with a Tetrazole-Substituted Calix[4]diquinone and Calix[4]dihydroquinone

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