Benzyl 4-methoxyphenyl

Benzyl 4-Methoxyphenyl Tellurium Dibromide3 1.16 g (2 mmol) of benzyl 4-methoxyphenyl tellurium diiodide and 1.2 g (4.3 mmol) of silver bromide suspended in 30 m/ of ethanol are stirred at 20° for 1 h. A few drops of40% hydrobromic acid are added. The yellow precipitate is filtered and extracted with cold benzene. Petroleum ether (b.p. 50-70°) is added to the extract to precipitate the dibromide. The dibromide is filtered, dissolved in the minimum volume of hot ethanol, and a few drops of 40% hydrobromic acid are added to the hot ethanol solution. The dibromide crystallizes on cooling as yellow platelets yield 0.75 g (78%) m.p. 153° (dec.). 

Six protective groups for alcohols, which may be removed successively and selectively, have been listed by E.J. Corey (1972B). A hypothetical hexahydroxy compound with hydroxy groups 1 to 6 protected as (1) acetate, (2) 2,2,2-trichloroethyl carbonate, (3) benzyl ether, (4) dimethyl-t-butylsilyl ether, (5) 2-tetrahydropyranyl ether, and (6) methyl ether may be unmasked in that order by the reagents (1) KjCO, or NH, in CHjOH, (2) Zn in CHjOH or AcOH, (3) over Pd, (4) F", (5) wet acetic acid, and (6) BBrj. The groups may also be exposed to the same reagents in the order A 5, 2, 1, 3, 6. The (4-methoxyphenyl)methyl group (=MPM = p-methoxybenzyl, PMB) can be oxidized to a benzaldehyde derivative and thereby be removed at room temperature under neutral conditions (Y- Oikawa, 1982 R. Johansson, 1984 T. Fukuyama, 1985). 

The starting material for the above step may be prepared as follows 5 g (0.016 mol) of N -(p-methoxyphenyl)-p-chlorobenzhydrazide hydrochloride and 4.75 g (0.018 mol) of benzyl levulinoyloxyacetate were heated In 25 ml of glacial acetic acid for 3 hours at 80°C. The solvent was then evaporated off under vacuum. The residue was taken up in chloroform and the solution was washed neutral by shaking with sodium bicarbonate solution and thereafter with water. After drying the chloroform solution, this was subjected to chromatography on aluminium oxide, the eluate was concentrated by evaporation and the viscous oil remaining as residue was crystallized by adding ether. The compound melted at 94°-95 t. The yield was 4.1 g which corresponds to 50.7% of the theoretical yield. 

Benzopyran-3-one, l,4-dihydro-6,7-dimethoxy-], 55, 45 Isocyamde, benzyl-, 55, 98 Isocyanide, butyl-, 55, 98 ISOCYANIDE, tert-butyl- [Isocyamde, 1,1-dimethylethyl-], 55, 96 Isocyamde, cyclohexyl-, 55, 98 Isocyamde, dodecanyl-, 55, 98 Isocyamde, ethyl, 55,98 Isocyamde, methyl, 55, 98 Isocyamde, phenyl-, 55, 98 (-)-2,3 4,6-Di-0-isopropylidene-2-keto-L-gulomc acid, hydrate [L-jcy/o-2-Hex-ulosomc acid, bis-<9-( 1 -mcthylcthyl-ldene)-], 55,80, 81 ISOXAZOl F, 3-(4-chlorophenv1)-5-(4-methoxyphenyl)-, 55, 39 Isoxazole,5 -(4-chloropheny l)-3-(4-me th-oxyphenyl)-, 55,42... 

C9H13NO 104-63-2) see Indeloxacine Phenmetrazine 7-(2-benzylaminoethyl)theophylline (C15H19N5O2 22680-61-1) see Fenetylline Theodrenaline benzyl [(2R,35)-3-amino-2-hydroxy-4-phenylbutyl](2-methylpropyl)carbamate monohydrochloride (C22H3[C1N20j 160232-11-1) see Amprenavir 2-benzylamino-l-(4-methoxyphenyl)propane (C17H21NO 43229-65-8) see Fenoterol Formoterol benzyl [3-[(2-aminophenyl)carbamoyl]propyl]methyl> carbamate... 

C27H33N30ft 89371-36-8) see Imidapril 7V-benzyl-7V-[l-methyl-2-(4-methoxyphenyl)ethyl]amine see under 2-benzylamino-l-(4-methoxyphenyl)propane ( )-7V-benzyl-7V-(l-methyl-2-(4-methoxyphenyl)ethyl]-amine... 

Primary 1,2-diamines can be obtained by hydrogenolysis of the benzylic N-auxiliary bond over Pd/C, e.g., the preparation of 249d. The cleavage is not selective in the presence of other benzylic bonds in the molecule, e.g., aryl substituents at Cl - C2. However, in the presence of methoxyphenyl or dimethoxyphenyl C substituents, the N substituents can be selectively removed, as exemplified by the preparation of the primary 1,2-diamine... 

Methoxyphenyl (PMP) ethers find occasional use as hydroxy protecting groups. Unlike benzylic groups, they cannot be made directly from the alcohol. Instead, the phenoxy group must be introduced by a nucleophilic substitution.185 Mitsunobu conditions are frequently used.186 The PMP group can be cleaved by oxidation with CAN. 

In an extension to the xanthenyl theme, the benzyl hydrogen was replaced with a substituted / -methoxyphenyl ring to give linker 35 (Scheme 10) [41]. Peptide amides were cleaved rapidly and in high purity with TFA-DCM (1 9) for 15 min or as a protected fragment with TFA-DCM (1 99) for 3-10 min. 

MAMP (Merrifield, Alpha-MethoxyPhenyl) resin 44 is an alternative to aldehyde linkers to construct TV-substituted amides [53], Nucleophilic displacement of the benzylic chloride with an amine followed by acylation yielded a secondary amide which was released upon a low ( 10%) concentration of TFA (Scheme 16). 

R = alkyl, alkenyl, alkynyl, aryl, acetate, ester, benzyl or silyl ether groups Scheme 6.15 Cleavage of methoxyphenyl methyl (MPM) ethers using clayan. 

At present, other CL amplifiers are recommended for the detection of superoxide in cells and tissue such as coelenterazine (2-(4-hydroxybenzyl)-6-(4-hydroxyphenyl)-8-benzyl-3,7-dihydroimidazo[l,2-a]pyrazin-3-one]) and its analogs CLA (2-methyl-6-phenyl-3,7-dihydroi-midazo[l,2-a]pyrazin-3-one]) and MCLA [2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimi-dazo[l,2-a]pyrazin-3-one]). It has been suggested that the origin of CL produced by these compounds is the oxidation of the acetamidopyrazine moiety [69,70]. Unfortunately, to our knowledge, there are still no reliable thermodynamic and kinetic data to validate the application of the above CL amplifiers for superoxide detection. Reichl et al. [71] proposed to use the photoprotein pholasin for the detection of superoxide and myeloperoxide activity in stimulated neutrophils. 

Synthesis of the dihydrothiophene derivatives was described by Flynn et al. [70] (depicted in Scheme 23) and involved the conversion of 3-butynol 92 to benzyl 3-butynal sulfide 93. Sonogashira coupling of the sulfide 93 with acetic acid 5-iodo-2-methoxyphenyl ester 94, produced the intermediate 95. Treatment of compound 95 with iodine resulted in a rapid and... 

Tertiary benzylic nitriles are useful synthetic intermediates, and have been used for the preparation of amidines, lactones, primary amines, pyridines, aldehydes, carboxylic acids, and esters. The general synthetic pathway to this class of compounds relies on the displacement of an activated benzylic alcohol or benzylic halide with a cyanide source followed by double alkylation under basic conditions. For instance, 2-(2-methoxyphenyl)-2-methylpropionitrile has been prepared by methylation of (2-methoxyphenyl)acetonitrile using sodium amide and iodomethane. In the course of the preparation of a drug candidate, the submitters discovered that the nucleophilic aromatic substitution of aryl fluorides with the anion of a secondary nitrile is an effective method for the preparation of these compounds. The reaction was studied using isobutyronitrile and 2-fluoroanisole. The submitters first showed that KHMDS was the superior base for the process when carried out in either THF or toluene (Table I). For example, they found that the preparation of 2-(2-methoxyphenyl)-2-methylpropionitrile could be accomplished h... 

Cycloaddition of p-methoxyphenyl azide to alkynic dipolarophiles at room temperature gives triazoles (697) and (698) (Equation (54)). A regiospecific addition is only observed in the case of Z = CH(OMe)2 <89H(29)967>. Phenyl azide and substituted benzyl azides undergo 1,3-dipolar cycloadditions with DM AD, phenylacetylene, and ethyl propiolate to afford 1-phenyl- and 1-benzyl-... 

Compound 142 was prepared by reacting 141 with chloroacetic acid under basic conditions which were accompanied by the loss of CO2. Acetylation and benzoylation of 141 with boiling AC2O or benzoyl chloride in pyridine yielded the corresponding 3-acetyl(benzoyl) derivatives 143 and 144, respectively <1994H(38)57>. Alkylation of 6-benzyl-5,6,7,8-tetrahydropyrido[4,3-tf pyrimidin-4(3//)-one 145 with l-(2-methoxyphenyl)-4-(2-chloroethyl)piper-azine afforded the 3-substituted derivative 146 <2000DEP19900544>. 

The dibenzarsenins (125) are prepared by the pyrolysis of a 10-benzyl-5,10-dihy-drodibenz[6,e]arsenin (equation 27). This reaction proceeds via a radical abstraction process. The parent (125 R = H) is unstable and could not be isolated, but the phenyl (125 R = Ph), tolyl (125 R = 4-MeCeH4) and p-methoxyphenyl (125 R = 4-MeOCeH4) derivatives were isolated. Like arsenin itself, (125) can act as a diene in the Diels-Alder reaction and maleic anhydride adducts were prepared for each of the above (77RTC265). 

Methoxyphenyl ethers can be cleaved by mild oxidants (Entry 10, Table 7.8). Because many acid-labile linkers are also readily oxidized, care must be taken when applying this deprotection strategy. Benzyl ethers have been removed from Tentagel-or PEGA-bound carbohydrates by catalytic hydrogenation using palladium nanoparticles [112],... 

U,5-Dihydroxy-2-methoxyphenyl-ethylamine, AP9U 3, U-D i hydroxy-o -[ (methylami no)-methyl]benzyl alcohol, AP92... 

Bis(p-methoxyphenyl) telluroxide (118) and the corresponding tellurone (119) have recently been shown to exhibit mild oxidizing properties towards easily oxidizable substrates. Thus the telluroxide (118) oxidizes thiocarbonyl compounds RR C=S to the corresponding ketone RR C—O364,365 and 3,4-di-f-butylpyrocatechol to 3,4-di-f-butyl-o-quinone.364 The tellurone (119) oxidizes benzyl alcohols to the corresponding carbonyl compounds, a reaction. .which is not observed with (118).366... 

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