Quinone Diazide Research Articles

Transition Metal-catalyzed Regioselective Direct C-H Arylations Using Quinone Diazide as Arylating Agent: A Mini Review

Abstract: Quinone diazides are a class of diazo compounds, having a planar six-membered ring system with diazo, carbonyl and al-kene groups in conjugation. Earlier it was used in optical, electronic, polymer materials etc. In the last few years, various rearrangements reactions and insertion reactions were explored by these diazo compounds via the formation of metallo-carbenoids. Recently, it has been used to incorporate phenol moieties to hydrocarbons or arene/heteroarenes systems via transition metal-catalyzed C-H bond activation. The reactions proceed via C-H bond insertion or migratory insertion of metal-carbenes. In many cases, the site-selectivities were obtained by the guidance of various directing groups (remova-ble or non-removable). At the same time, several asymmetric approaches were also studied to incorporate phenol deriv-atives to arenes/heteroarenes furnishing compounds showing axial chirality with high stereoselectivity. In this review, we will mainly focus on directed regioselective arylation with quinone diazides under transition metal catalysis through C-H bond activation.

Rhodium-Catalyzed N-Arylation of 2-Pyridones Enabled by 1,6-Acyl Migratory Rearrangement of 2-Oxypyridines

An efficient rhodium-catalyzed dearomative rearrangement of 2-oxypyridines with quinone diazides has been developed for the direct synthesis of N-arylated pyridones, in which a novel 1,6-O-to-O rather than 1,4-O-to-C acyl rearrangement has been achieved under mild reaction conditions.

Iridium(III)-Catalyzed Intermolecular Mild N-Arylation of Aliphatic Amides Using Quinoid Carbene: A Migratory Insertion-Based Approach

An efficient Ir(III)-catalyzed straightforward intermolecular N-arylation of acyclic aliphatic amides has been achieved using quinone diazide as a coupling partner. The reaction has been developed under simple and mild reaction conditions with a broad substrate scope. The bidentate picolinamide group is essential for successful transformation. Mechanistic studies and DFT calculations highlighted the migratory insertion-based pathway. The developed method exhibits different reactivities compared to the reactions of acyclic aliphatic amides using related diazo/azide congeners under Rh(III)/Ir(III) catalysis.

Recent quinone diazide based transformations via metal–carbene formation

Recent advancements in versatile synthetic transformations using quinone diazide based metal carbenes have been summarized.

Rhodium(iii)-catalyzed synthesis of spirocyclic isoindole N-oxides and isobenzofuranones via C-H activation and spiroannulation.

Rhodium(iii)-catalyzed mild and oxidative [4+1] spiroannulation has been realized via C-H activation of oximes and benzoic acids with 1-diazonaphthelen-2(1H)-ones as coupling reagents. This transformation integrates C-H activation and dearomatization and provides a direct approach to spirocyclic isoindole N-oxides and isobenzofuranones with functional group tolerance.

Enantioselective Synthesis of Azamerone.

A concise and selective synthesis of the dichlorinated meroterpenoid azamerone is described. The paucity of tactics for the synthesis of natural-product-relevant chiral organochlorides motivated the development of unique strategies for accessing these motifs in enantioenriched forms. The route features a novel enantioselective chloroetherification reaction, a Pd-catalyzed cross-coupling between a quinone diazide and a boronic hemiester, and a late-stage tetrazine [4+2]-cycloaddition/oxidation cascade.

Synthesis and some transformations of polybrominated quinone diazides

The reduction of polybrominated o- and p-nitrophenols with granular tin in concentrated aqueous HCl gave polybrominated aminophenols which were diazotized with sodium nitrite in concentrated sulfuric acid at 0°C to obtain polybrominated o- and p-quinone diazides. Their thermolysis with elimination of nitrogen generated ketocarbenes which reacted with acetylacetone to form insertion products at the activated methylene group. Ketocarbenes generated from o-quinone diazides reacted with typical dipolarophiles such as acetonitrile, benzonitrile, styrene, and phenylacetylene to afford the corresponding [3 + 2]-cycloaddition products.

Rhodium(III)-Catalyzed C6-Selective Arylation of 2-Pyridones and Related Heterocycles Using Quinone Diazides: Syntheses of Heteroarylated Phenols

An efficient, direct C6-arylation of 2-pyridones has been successfully accomplished with quinone diazides under Rh(III)-catalyzed redox-neutral conditions. The optimized method is simple, mild, and highly regioselective with a broad substrate scope. The strict regioselectivity is guided by the pyridyl substituent attached to the nitrogen of the pyridone ring. As the directing 2-pyridyl group can easily be removed at any suitable stage after functionalization, the method provides a facile access to complex heteroarylated phenol moieties by wide-ranging heterocyclic scaffolds.

ChemInform Abstract: Cp*Rh(III) and Cp*Ir(III)‐Catalyzed Redox‐Neutral C—H Arylation with Quinone Diazides: Quick and Facile Synthesis of Arylated Phenols.

ChemInform Abstract: Cp*Rh(III) and Cp*Ir(III)‐Catalyzed Redox‐Neutral C—H Arylation with Quinone Diazides: Quick and Facile Synthesis of Arylated Phenols.

Cp*Rh(III) and Cp*Ir(III)-catalysed redox-neutral C-H arylation with quinone diazides: quick and facile synthesis of arylated phenols.

Cp*Rh(III)- and Cp*Ir(III)-catalysed direct C-H arylation with quinone diazides as efficient coupling partners is disclosed. This redox-neutral protocol offers a facile, operationally simple and environmentally benign access to arylated phenols. The reaction represents the first example of Cp*Ir(III)-catalysed C-H direct arylation reaction.

Quinone Diazides for Olefin Functionalization

AbstractThe utility of quinone diazides in materials science is vast and well‐documented, yet this potentially useful motif has languished in the annals of organic synthesis. Herein we show that modern tools of catalysis can be employed with free or suitably masked quinone diazides to unleash the power of these classic diazo compounds in the context of both inter‐ and intramolecular olefin cyclopropanation.

Quinone diazides for olefin functionalization.

The utility of quinone diazides in materials science is vast and well-documented, yet this potentially useful motif has languished in the annals of organic synthesis. Herein we show that modern tools of catalysis can be employed with free or suitably masked quinone diazides to unleash the power of these classic diazo compounds in the context of both inter- and intramolecular olefin cyclopropanation.

NO scavenging by 3-hydroxyanthranilic acid and 3-hydroxykynurenine: N-nitrosation leads via oxadiazoles to o-quinone diazides

The tryptophan metabolites kynurenine, 3-hydroxykynurenine, anthranilic, 3-hydroxyanthranilic and 3-methoxyanthranilic acids were compared with regard to diazotation by ·NO or NO +, using three different donors, nitrite at pH 5, PAPA-NONOate at pH 7.4 and NO +SbF 6 − at pH 2.0. With all three sources of NO species, 3-hydroxykynurenine and 3-hydroxyanthranilic acid were readily nitrosated, thereby forming an intensely yellow compound. Nitrosation of the non-hydroxylated analogs did not lead to colored products within the period of observation. Competition experiments, using PAPA-NONOate as NO donor, showed that 3-hydroxyanthranilic acid is a more potent NO scavenger than N-acetylcysteine. Nitrosation of 3-hydroxykynurenine and 3-hydroxyanthranilic acid leads, presumably via a nitrosamine intermediate, to a diazonium ion, which forms an oxadiazole tautomerizing to a yellow o-quinone diazide. While the diazonium-derived quinone diazide is apparently the sole product detected directly after incubation of 3-hydroxyanthranilic acid, additional substances are formed from 3-hydroxykynurenine. Contrary to rapid carbenium ion formation from diazonium ions of non-hydroxylated anilines, nitrogen is practically not released from oxadiazoles/quinone diazides at moderate temperatures. Since carbenium ions are known to cause adduct formation with other biomolecules, and since non-hydroxylated anilines and their aminophenol analogs differ in their reactions following diazotation, these findings should be of relevance for the relative toxicity of anilines.

Paradigms and Paradoxes: Resonance Stabilization in Diazophenoxides (Quinone Diazides)

Diazophenoxides (quinone diazides) constitute an interesting class of compounds that are seemingly high-energy species on the nonaromatic/aromatic interface. With appropriate substitution and/or annelation, they have found use in the fields of explosives, medicine, and photolithography. Thermochemical information about them is sparse. To aid further understanding of these important chemical species, the current paper discusses a few extant enthalpies of formation from which we tentatively derive a resonance energy of ca. 15 kJ-mol−1 for the parent, p-species, 4-diazo-2,5-cyclohexadiene-1-one. Interestingly, this value is nearly identical to that recently found for the likewise conjugated diazo compound, ethyl diazoacetate.

FT-EPR and HPLC study of the mechanism of 4-chlorophenol photolysis

The mechanism of 4-chlorophenol (4CP) photolysis was investigated with the aid of Fourier Transform Electron Paramagnetic Resonance (FT-EPR) and pulsed-laser photolysis combined with High Performance Liquid Chromatography (HPLC) detection-of stable (diamagnetic) products. With FT-EPR transient free radicals produced by pulsed-laser excitation of solutions of 4CP in alcohols could be identified. Time profiles of the FT-EPR spectra provided information on reaction kinetics and Chemically Induced Dynamic, Electron Polarization (CIDEP) effects. It was found that 4CP photolysis in alcohols leads to the simultaneous formation of the phenoxyl radical and radicals produced by hydrogen abstraction from the solvent. CIDEP patterns establish that these radicals are formed in a reaction sequence involving a triplet state precursor and radical pair intermediate. Results of earlier transient optical absorption measurements indicate that the triplet precursor must be the carbene 4-oxocyclohexa-2,5-dienylidene. This assignment is supported by the finding that photolysis of quinone diazide in a hydrogen-donating solvent gives the same free radical products as those obtained from 4CP. The formation of the phenoxyl radical intermediate accounts for the finding that photolysis of deoxygenated solutions of 4CP in alcohols gives phenol as stable diamagnetic product. By contrast, photolysis of aerated and deoxygenated aqueous solutions of 4CP produces benzoquinone and hydroquinone as primary products, respectively.

ChemInform Abstract: Quinone Diazides and Enaminones as a Source of New Azo Compounds with Potential Nonlinear Optical Properties.

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Quinone Diazides and Enaminones as a Source of New Azo Compounds with Potential Nonlinear Optical Properties

Quinone Diazides and Enaminones as a Source of New Azo Compounds with Potential Nonlinear Optical Properties

Base‐Catalyzed Dehalogenation of 2,6‐Di‐tert‐butyl‐4‐iodophenol Formation and Structure of a New Oxocyclohexadienylidene Bisphenol

Abstract2,6‐Di‐tert‐butyl‐4‐iodophenol (1) does not react to the keto carbene 4 under strongly basic conditions and exclusion of oxygen, in contrast to a report in the literature. In the presence of oxygen, however, oxidation takes place. Reaction times and product pattern strongly depend on the concentration of O2. Besides biphenyl 2, diphenoquinone 3, and quinone 5, a new (oxocyclohexadienylidene)bisphenol 6 was isolated, and its molecular structure was determined by X‐ray crystallography. A radical mechanism is suggested for the formation of the above products from 1. The bisphenol 6 was also synthesized by thermolysis of the quinone diazide 11 in the presence of 3.

Chemistry and spectroscopy of aromatic diradicals in cryogenic matrices

Abstract

Chemical Aspects of Offset Printing

In the last ten years, offset printing has achieved the broadest application on the printing market due to its inherent advantages. Light sensitive offset plates for contact UV exposure are mainly used at present. The chemistry of these plates are based on the photoreactions of quinone diazides, diazo resins and radical photopolymers. For the further development of offset printing plates the improvement of the light sensitivity and extension of spectral sensitivity to the visible range is a market-driven requirement to realize transfer of computer stored informations by laser. For this requirement electrophotographic systems, systems based on silver halides and photoinduced polymerizations are most important. New literature data dealing with these systems in relation to printing plates are summarized.