4546-20-7

Upstream product

• 100-17-4 para-methoxynitrobenzene 
• 1516-21-8 4-methoxynitrosobenzene 
• 104-94-9 4-methoxy-aniline 
• 124-40-3 dimethyl amine 
• 66682-84-6 N-(4-Methoxyphenyl)acetohydroxamsaeure 

Downstream Products

• 1562-94-3 4,4'-azoxy anisole 
• 19064-76-7 N-benzylidene-4-methoxyaniline oxide 
• 3170-89-6 C₂₂H₂₂N₄O₆ 
• 3170-88-5 Iminokohlensaeure-(2,2,2-trichlor-ethylester)-(4-methoxy-phenylhydroxylamid) 
• 3170-90-9 2-(N-hydroxy-4-methoxy-anilino)-benzo[e][1,3]oxazin-4-one 
• 3352-39-4 Iminokohlensaeure-(2,4-dimethyl-phenylester)-(4-methoxy-phenylhydroxylamid) 
• 126901-18-6 2-Bromo-N-hydroxy-N-(4-methoxy-phenyl)-propionamide 
• 110606-21-8 N-p-methoxyphenyl-2-furylacrylohydroxamic acid 
• 97369-64-7 3-<<(4-Methoxyphenyl)imino>methyl>-1-methylpyridinium-iodid-N-oxid 
• 126901-26-6 N-(4-Methoxyphenyl)pivalohydroxamsaeure 
• 68221-23-8 N-Benzoyl-N-p-anisylhydroxylamin 
• 66682-84-6 N-(4-Methoxyphenyl)acetohydroxamsaeure 
• 126926-32-7 2-Bromo-N-hydroxy-N-(4-methoxy-phenyl)-acetamide 
• 73747-09-8 N-Hydroxy-N-(4-methoxy-phenyl)-formamide 

Relevant academic research and scientific papers

α-Effect Menschutkin alkylations

The Menschutkin-type alkylation of substituted N-methylanilines with methyl arenesulfonates is compared to the same reaction with substituted N- phenylhydroxylamines. The α-effects are small but measurable. The Hammett ρ parameters are not useful in this reaction series as an index of transition- state character. The use of β(1g)(Me) parameters along with β(nuc) values allows the transition states to be placed on the energy surface. The pattern is that the α-nucleophiles form tighter transition states than the normal nucleophiles. The size of the α-effect is related to the ionization potentials (IPs) computed by the AM1 Hamiltonian for a wide variety of reactions showing the α-effect. The larger α-effects depend more greatly on the IP.

Light-Promoted C–N Coupling of Aryl Halides with Nitroarenes

A photochemical C–N coupling of aryl halides with nitroarenes is demonstrated for the first time. Catalyzed by a NiII complex in the absence of any external photosensitizer, readily available nitroarenes undergo coupling with a variety of aryl halides, providing a step-economic extension to the widely used Buchwald–Hartwig C–N coupling reaction. The method tolerates coupling partners with steric-congestion and functional groups sensitive to bases and nucleophiles. Mechanistic studies suggest that the reaction proceeds via the addition of an aryl radical, generated from a NiI/NiIII cycle, to a nitrosoarene intermediate.

Polyfunctionalized biaryls accessed by a one-pot nucleophilic aromatic substitution and sigmatropic rearrangement reaction cascade under mild conditions

A practical synthetic method has been developed for polyfunctionalized biaryls based on a facile one-pot nucleophilic aromatic substitution (SNAr) reaction and [5,5]- or [3,3]-sigmatropic rearrangement reaction cascade. Under mild basic conditions, N-arylhydroxylamines reacted with o-activated fluoro (het)arenes to form N,O-diarylhydroxylamine intermediates which underwent spontaneously selective [5,5]-sigmatropic rearrangement reaction to produce diverse functionalized 4-amino-4′-hydroxy-1,1′-biaryls. A sequential SNAr reaction and [3,3]-sigmatropic rearrangement took place between N-arylhydroxylamines and 2-fluoropyridine derivatives or 4-fluorobenzonitrile to afford functionalized 2-amino-2′-hydroxy-1,1′-biaryls. As invaluable and unique building blocks, the resulting biaryls were applied in the straightforward synthesis of N2,O2-coronarene, carbazole, aza- and diaza carbazole derivatives.

Selective Reduction of Nitroarenes to Arylamines by the Cooperative Action of Methylhydrazine and a Tris(N-heterocyclic thioamidate) Cobalt(III) Complex

We report an efficient catalytic protocol that chemoselectively reduces nitroarenes to arylamines, by using methylhydrazine as a reducing agent in combination with the easily synthesized and robust catalyst tris(N-heterocyclic thioamidate) Co(III) complex [Co(κS,N-tfmp2S)3], tfmp2S = 4-(trifluoromethyl)-pyrimidine-2-thiolate. A series of arylamines and heterocyclic amines were formed in excellent yields and chemoselectivity. High conversion yields of nitroarenes into the corresponding amines were observed by using polar protic solvents, such as MeOH and iPrOH. Among several hydrogen donors that were examined, methylhydrazine demonstrated the best performance. Preliminary mechanistic investigations, supported by UV-vis and NMR spectroscopy, cyclic voltammetry, and high-resolution mass spectrometry, suggest a cooperative action of methylhydrazine and [Co(κS,N-tfmp2S)3] via a coordination activation pathway that leads to the formation of a reduced cobalt species, responsible for the catalytic transformation. In general, the corresponding N-arylhydroxylamines were identified as the sole intermediates. Nevertheless, the corresponding nitrosoarenes can also be formed as intermediates, which, however, are rapidly transformed into the desired arylamines in the presence of methylhydrazine through a noncatalytic path. On the basis of the observed high chemoselectivity and yields, and the fast and clean reaction processes, the present catalytic system [Co(κS,N-tfmp2S)3]/MeNHNH2 shows promise for the efficient synthesis of aromatic amines that could find various industrial applications.

Selective Photoinduced Reduction of Nitroarenes to N-Arylhydroxylamines

We report the selective photoinduced reduction of nitroarenes to N-arylhydroxylamines. The present methodology facilitates this transformation in the absence of catalyst or additives and uses only light and methylhydrazine. This noncatalytic photoinduced transformation proceeds with a broad scope, excellent functional-group tolerance, and high yields. The potential of this protocol reflects on the selective and straightforward conversion of two general antibiotics, azomycin and chloramphenicol, to the bioactive hydroxylamine species.

Tandem selective reduction of nitroarenes catalyzed by palladium nanoclusters

We report a catalytic tandem reduction of nitroarenes by sodium borohydride (NaBH4) in aqueous solution under ambient conditions, which can selectively produce five categories of nitrogen-containing compounds: anilines, N-aryl hydroxylamines, azoxy-, azo- and hydrazo-compounds. The catalyst is in situ-generated ultrasmall palladium nanoclusters (Pd NCs, diameter of 1.3 ± 0.3 nm) from the reduction of Pd(OAc)2 by NaBH4. These highly active Pd NCs are stabilized by surface-coordinated nitroarenes, which inhibit the further growth and aggregation of Pd NCs. By controlling the concentration of Pd(OAc)2 (0.1-0.5 mol% of nitroarene) and NaBH4, the water/ethanol solvent ratio and the tandem reaction sequence, each of the five categories of N-containing compounds can be obtained with excellent yields (up to 98%) in less than 30 min at room temperature. This tunable catalytic tandem reaction works efficiently with a broad range of nitroarene substrates and offers a green and sustainable method for the rapid and large-scale production of valuable N-containing chemicals.

A general and scalable synthesis of polysubstituted indoles

A consecutive 2-step synthesis of N-unprotected polysubstituted indoles bearing an electron-withdrawing group at the C-3 position from readily available nitroarenes is reported. The protocol is based on the [3,3]-sigmatropic rearrangement of N-oxyenamines generated by the DABCO-catalyzed reaction of N-arylhydroxylamines and conjugated terminal alkynes, and delivers indoles endowed with a wide array of substitution patterns and topologies.

Highly Selective and Solvent-Dependent Reduction of Nitrobenzene to N-Phenylhydroxylamine, Azoxybenzene, and Aniline Catalyzed by Phosphino-Modified Polymer Immobilized Ionic Liquid-Stabilized AuNPs

Gold nanoparticles stabilized by phosphine-decorated polymer immobilized ionic liquids (AuNP@PPh2-PIILP) is an extremely efficient multiproduct selective catalyst for the sodium borohydride-mediated reduction of nitrobenzene giving N-phenylhydroxylamine, azoxybenzene, or aniline as the sole product under mild conditions and a very low catalyst loading. The use of a single nanoparticle-based catalyst for the partial and complete reduction of nitroarenes to afford three different products with exceptionally high selectivities is unprecedented. Under optimum conditions, thermodynamically unfavorable N-phenylhydroxylamine can be obtained as the sole product in near quantitative yield in water, whereas a change in reaction solvent to ethanol results in a dramatic switch in selectivity to afford azoxybenzene. The key to obtaining such a high selectivity for N-phenylhydroxylamine is the use of a nitrogen atmosphere at room temperature as reactions conducted under an inert atmosphere occur via the direct pathway and are essentially irreversible, while reactions in air afford significant amounts of azoxy-based products by virtue of competing condensation due to reversible formation of N-phenylhydroxylamine. Ultimately, aniline can also be obtained quantitatively and selectively by adjusting the reaction temperature and time accordingly. Introduction of PEG onto the polyionic liquid resulted in a dramatic improvement in catalyst efficiency such that N-phenylhydroxylamine could be obtained with a turnover number (TON) of 100000 (turnover frequency (TOF) of 73000 h-1, with >99% selectivity), azoxybenzene with a TON of 55000 (TOF of 37000 h-1 with 100% selectivity), and aniline with a TON of 500000 (TOF of 62500 h-1, with 100% selectivity). As the combination of ionic liquid and phosphine is required to achieve high activity and selectivity, further studies are currently underway to explore whether interfacial electronic effects influence adsorption and thereby selectivity and whether channeling of the substrate by the electrostatic potential around the AuNPs is responsible for the high activity. This is the first report of a AuNP-based system that can selectively reduce nitroarenes to either of two synthetically important intermediates as well as aniline and, in this regard, is an exciting discovery that will form the basis to develop a continuous flow process enabling facile scale-up.

Tandem Chiral Cu(II) Phosphate-Catalyzed Deoxygenation of Nitrones/Enantioselective Povarov Reaction with Enecarbamates

A new catalytic enantioselective tandem deoxygenation/aza-Diels-Alder reaction of nitrones with enecarbamates was serendipitously discovered in the presence of chiral copper(II) diphosphate complexes. This process affords a wide range of 4-aminotetrahydroquinolines in respectable yields under mild conditions with good to excellent ee values.

Highly Electron-Deficient Pyridinium-Nitrones for Rapid and Tunable Inverse-Electron-Demand Strain-Promoted Alkyne-Nitrone Cycloaddition

Highly accelerated inverse-electron-demand strain-promoted alkyne-nitrone cycloaddition (IED SPANC) between a stable cyclooctyne (bicyclo[6.1.0]nonyne (BCN)) and nitrones delocalized into a Cα-pyridinium functionality is reported, with the most