Of 4-methoxyaniline

In the presence of water, oxidation of 4-methoxyaniline gives the quinone imine. The example 54 is converted by oxidation and ring closure to the tetrahy-drocarbazole [164],... 

Chemoselective oxidation of 4-methoxyanilines to quinonimines can be achieved in the presence of tricarbonyl(ri4-cyclohexadiene)iron complexes. This transformation has been used for the synthesis of carbazoles via intermediate tricarbonyliron-coordinated 4b,8a-dihydrocarbazol-3-one complexes (Scheme 1.24) [57]. 

The condenser is not cooled and the collector tip is at times gently heated with a heat gun to prevent crystallization of 4-methoxyaniline in the distillation apparatus. 

Lutidine and methyl iodide added to an ice-cooled soln. of 4-methoxyaniline in dimethylformamide, allowed to stand ca. 0.5 hr. in the cooling bath and 1.5 hrs. at room temp. (4-methoxyphenyl)trimethylammonium iodide. Y 87%. - 2,6-... 

Scheme 3,36 Organocatalytic Povarov reactions of 4-methoxyaniline derived imines with 2- and...

Section 1.7.2 discusses the basicity of 4-methoxyaniline, 2-nitroaniline and 3-nitroaniline... 

Fig. 1 Reflectance scans of a chromatogram track with 100 ng each of 1 = 2,4-diamino-6-methylphenol, 2 = 3-chloro-4-methoxyaniline, 3 = aniline, 4 = 4-bromoaniline, 5 = 3-chloro-aniline, 6 = 2,6-dimethylaniline, 7 = 2-methyl-6-ethylaniline and 8 = 2-chloroaniline.

This iron-ate complex 19 is also able to catalyze the reduction of 4-nitroanisole to 4-methoxyaniline or Ullmann-type biaryl couplings of bis(2-bromophenyl) methylamines 31 at room temperature. In contrast, the corresponding bis(2-chlor-ophenyl)methylamines proved to be unreactive under these conditions. A shift to the dianion-type electron transfer(ET)-reagent [Me4Fe]Li2 afforded the biaryl as well with the dichloro substrates at room temperature, while the dibromo substrates proved to be reactive even at —78°C under these reaction conditions. This effect is attributed to the more negative oxidation potential of dianion-type [Me4Fe]Li2. 

Amine complexes stabilized with phosphine ligands of the type [AuL(PR3)]+ have been obtained for L = bipy,2310 phen,2310,231 quinoline,23 1 acridine,2311 benzo[h]quinoline,2311 naphthyr-idine (388)2311 2,2 -biquinoline,2311 di-2-pyridyl-ketone,2311 di-2-pyridylamine,2311 2-(2-pyridyl)-benzimidazole, 2311 ferrocenylpyridine, 2-nitroaniline,2312 4-methoxyaniline,2312 NHPh2, 2 NHEt2,2312 NMe3,2312 quinuclidine,2313 NEt3,2314 2-aminothiazoline,2315 histidine,2316... 

Coupling of 5-aminobenzotriazole 297 with a diazonium salt derived from 4-methoxyaniline generates diazo derivative 298. Conversion of the amino group into maleinimide produces dye 299 (Scheme 45). Diels-Alder cycloadditions of dye 299 to diene tagged nucleotides allows for their efficient labeling <2002CC2100>. 

Preparation of /V-allyl-2-chloro-4-methoxyaniline A mixture of 2-chloro-... 

Several reactions of imines of synthetic utility are reported. Nitric oxide reacts with A-benzylidene-4-methoxyaniline (18) in ether to give 4-methoxybenzenediazonium nitrate (19) and benzaldehyde. Two mechanisms are proposed, both involving nitrosodiazene (20), and the preferred route is suggested to involve direct electrophilic reaction of NO to the imine double bond, favoured by the polarity of the latter. 

A very remote secondary H/D isotope effect has been measured for the 2 + 2-cycloaddition of TCNE to 2,7-dimethylocta-2,fran -4,6-triene. The reaction of nitric oxide with iV-benzylidene-4-methoxyaniline to produce 4-methoxybenzenediazonium nitrate and benzaldehyde is thought to proceed via a 2 + 2-cycloaddition between nitric oxide and the imine double bond. A novel mechanism for the stepwise dimerization of the parent silaethylene to 1,3-disilacyclobutane involves a low-barrier [1,2]-sigmatropic shift. Density functional, correlated ab initio calculations, and frontier MO analysis support a concerted 2 + 2-pathway for the addition of SO3 to alkenes. " The enone cycloaddition reactions of dienones and quinones have been reviewed. The 2 + 2-photocycloadditions of homochiral 2(5H)-furanones to vinylene carbonate are highly diastereoisomeric. ... 

Two stable conformations of 7V-(l-pyrenylmethyl)-A -methyl-4-methoxyaniline, the linear and bent (V-like) forms are depicted in Scheme 5.3 (He et al. 2004). 

Palladium-catalyzed amination has also been used to prepare aminoquinazolines substituted in the benzo ring <2002JA1594, 2003TL7533>. The reactions were peformed on solid support and involved amination of all four chloro isomers with 4-methoxyaniline <2002JA1594>, or the amination of 6-bromo or 6- or 7-chloroquinazoline derivatives with a variety of aliphatic amines <2003TL7533>. 

Two further unusual examples involve a different bicyclic system and an acyclic system as precursors. In the first instance, use is made of the reactivity of a pyrrolo[2,3-<7]-l,3-oxazin-4-one 178 (Equation 67). Treatment of this compound with hydrazine hydrate afforded the 3-amino derivative 179a while reaction with 4-methoxyaniline produced 179b <2000IJB764>. 

Cells, Treatment, and Chromosome Analysis. About 4 X 105 CHO-K1 cells (Flow Laboratories, Scotland) were seeded into Ham s F10 medium (Flow) supplemented with 10 newborn calf serum (Flow). These cells were incubated at 37 °C and 5 C02 in 25-cm3 tissue culture flasks. Twenty-four hours later, the cells were exposed for 1 h at 37 °C to a maximum of 50 /zL of drinking water concentrate (neutral fraction) in a total volume of 3 mL of Ham s F10, without serum. As a positive control, 4-methoxyaniline, dissolved in DMSO, was used. 

Nitro-4-methoxyaniline has been prepared by heating nitro-hydroquinone dimethyl ether with aqueous ammonia 2 by heating the tetramethylammonium salt of 3-nitro-4-aminophenol 3 by the hydrolysis of 2-nitro-4-methoxyacetanilide la with alcoholic potassium hydroxide 11 lc or hydrochloric acid ld and by the hydrolysis of the />-toluenesul fonamide,4 the 3-nitrobenzenesul-fonamide,5 the 3-nitro-/>-toIuenesulfonamide,3 and the acetyl derivative of the />-toluenesulfonamide6 of 2-nitro-4-methoxyani-line with concentrated sulfuric acid. 

Another approach uses the coupling reaction of p-anisidine. In the presence of H202 and peroxidase (16), an oxidation product that contains two aromatic rings, benzoquinone-4-methoxyaniline, is formed stoichiometri-cally (92). Equations 14-16 indicate that an electron donor or hydrogen donor is required for peroxidase-mediated decomposition of H202. In two natural waters and one soil suspension, peroxidatic activity was identified by the stoichiometric removal of p-anisidine by the addition of H202 (in the dark) (16). This procedure provides an independent corroboration of the results obtained by Moffett and Zafiriou (1). However, this method does not quantify the relative importance of peroxidases versus catalases in the decomposition of H202. 

J Lantos, UATh Brinkman, RW Frei. Residue analysis of metoxuron and its breakdown product (3-chloro-4-methoxyaniline) by thin-layer and high-performance liquid chromatography with fluorescence detection. J Chromatogr 292 117-127, 1984. 

S)-Proline also catalyzed Mannich reactions in a three-component (donor aldehyde, 4-methoxyaniline, arylaldehyde) protocol - that is, without preformation of imine (Table 2.14) [71b, 82]. (For experimental details see Chapter 14.2.2). This three-component format also afforded the syn-Mannich products in good yields with high diastereoselectivity and enantioselectivities when slow addition of donor aldehyde and/or formation of the imine prior to addition of donor aldehyde was used at a lower reaction temperature, such —20 °C. Reactivity of benzaldehyde and of N-PMP-imine of benzaldehyde as acceptors was compared in the... 

Conditions Entries 1-3 To a mixture of ArCHO (0.5 mmol), 4-methoxyaniline (0.5 mmol), and (S)-proline (0.15 mmol) in DMF (3 mL), donor aldehyde (5.0 mmol) in DMF (2 mL) was slowly added (0.2 mL min-1) at —20 °C. The mixture was stirred at the same temperature for 4-10 h. The mixture was diluted with Et20 and reduction performed by addition of NaBH4 [71b]. Entries 4 and 5 After stirring a solution of ArCHO (1.0 mmol), 4-methoxyaniline (1.1 mmol), and (S)-proline (0.1 mmol) in N-methyl-2-pyrrolidinone (1.0 mL) for 2 h at rt, propionaldehyde (3.0 mmol) was added to the mixture at -20 °C, and stirring was continued for 20 h at the same temperature. The reaction was worked-up and reduction with NaBH4 performed without purification [82]. 

S)-Proline also catalyzed Mannich reactions of ketone donors in a three-component (donor ketone, 4-methoxyaniline, aryaldehyde) protocol, as shown in Table 2.16 [84b, 90, 91]. In these three component reactions, the C-C bond formation occurred at both a-positions of unsymmetrical alkyl ketones (entry 3), and the ratio of the regioisomers depended on the reactant ketones and aldehydes. When the reaction was performed using a ketone donor possessing an a-hydroxy or methoxy group, C-C bond formation occurred exclusively at the oxy-substituted a-carbon (entries 5-7) the major diastereomer was again the syn-product. The enantioselectivities of (S)-proline-catalyzed three-component... 

Method B After stirring a solution of ArCHO (1.0 mmol), 4-methoxyaniline (1.1 mmol), and (S)-proline (0.1 mmol) in N-methyl-2-pyrrolidinone (1.0 mL) for 2 h at r.t., propionaldehyde (3.0 mmol) was added to the mixture at — 20 °C, and stirring continued for 20 h at the same temperature. The reaction was worked-up and reduction with NaBH4 was performed without purification. 

It was shown (00JFC( 104)263) that perfluoro-2-methylpent-2-ene and perfluoro-5-azanon-4-ene smoothly react with two moles of aniline, 4-fluoroaniline, and 4-methoxyaniline in the presence of three moles of Et3N in acetonitrile, forming derivatives of quinoline and quinazoline. 

Bristol-Myers Squibb in partnership with Otsuka has recently marketed aripiprazole for the treatment of schizophrenia. The synthesis (Scheme 20) begins with acylation of 3-methoxyaniline followed by Friedel-Crafts ring closure to give quinolinone 67. Hydrogenation provides dihydroquinolinone 68, which is treated with 1,4-dibromobutane in the presence of K2CO3 to afford 69. Compound 69 was treated with Nal and then alkylated with 2,3-dichlorophenylpiperazine to give aripiprazole (5). 

Phenylpropargyl aldehyde and 4-methoxyaniline were refluxed in a benzene solution in the presence of a catalytic amount of p-toluenesulfonic acid under Dean-Stark conditions. After cooling the mixture was filtered through silica gel to remove residual amine. The imine purity was checked by H-NMR and the product isolated. 

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