Ethyl phenyl ether, substituted

Ethyl phenyl ether, substituted 85.5 357.7 Correlation 2005DEN/TUM... 

For the addition of ethylene, EtOAc as solvent was particularly advantageous and gave 418 in 60% yield (Scheme 6.86). The monosubstituted ethylenes 1-hexene, vinylcyclohexane, allyltrimethylsilane, allyl alcohol, ethyl vinyl ether, vinyl acetate and N-vinyl-2-pyrrolidone furnished [2 + 2]-cycloadducts of the type 419 in yields of 54—100%. Mixtures of [2 + 2]-cycloadducts of the types 419 and 420 were formed with vinylcyclopropane, styrene and derivatives substituted at the phenyl group, acrylonitrile, methyl acrylate and phenyl vinyl thioether (yields of 56-76%), in which the diastereomers 419 predominated up to a ratio of 2.5 1 except in the case of the styrenes, where this ratio was 1 1. The Hammett p value for the addition of the styrenes to 417 turned out to be -0.54, suggesting that there is little charge separation in the transition state [155]. In the case of 6, the p value was determined as +0.79 (see Section 6.3.1) and indicates a slight polarization in the opposite direction. This astounding variety of substrates for 417 is contrasted by only a few monosubstituted ethylenes whose addition products with 417 could not be observed or were formed in only small amounts phenyl vinyl ether, vinyl bromide, (perfluorobutyl)-ethylene, phenyl vinyl sulfoxide and sulfone, methyl vinyl ketone and the vinylpyri-dines. 

Substitution in the a- or 7-position of the allyl group increases the rate of rearrangement the crotyl ether of 2,4-dichlorophenol rearranges more rapidly than the allyl ether.46 a-Ethylcrotyl phenyl ether rearranges to the extent of 10% in twenty-four hours at 120°." a-Ethyl-... 

Reaction of ethyl iodoacetate with an excess (5 equiv) of pyrrole in the presence of 2-methyloxirane and BusSnSnBus led to the desired substitution product 1011 in 43% yield, in addition to an undetermined quantity of ethyl phenyl-acetate 1012 (Equation 239), indicating reactivity with the benzene solvent under the reaction conditions <1999TL2677>. The less toxic solvent, methyD-butyl ether (MTBE), provided product 1011 in improved (64%) yield. 

A regioselective method affording directly 3-phenyl-5-substituted isoxazoles 341, without isolation of isoxazoline intermediates, exploited reactions of NH2OH and a-benzotriazolyl-a,/3-unsaturated ketones 340, stereoselectively generated from benzotriazolylacetophenone and aldehydes in the presence of piperidine (Scheme 83) <2001JOC6787>. Treatment of /3-lithiated benzotriazolylvinyl ethyl ether with acid chlorides followed by cyclocondensation with hydroxylamine hydrochloride gave 4-benzotriazolyl-substituted isoxazoles <2005S245>. 

Sekiguchi, S., Ohtsuka, L, Okada, K. Aromatic nucleophilic substitution. 11. Effects of ortho substituents on the rates of the Smiles rearrangements of ( 3-acetylamino)ethyl-2-X-4-Y-6-Z-l-phenyl ethers with potassium hydroxide in aqueous dimethyl sulfoxide. J. Org. Chem. 1979, 44(14), 2556-2560. 

The reaction of ethyl 2,4,6-trinitrophenyl ether with aniline in dimethyl sulfoxide (DMSO) in the presence of Dabco occurs in two stages via the intermediate (6). Kinetic studies show that proton transfer is rate-limiting both in the formation of the intermediate and in the subsequent acid-catalysed decomposition to give 2,4,6-trinitrodiphenylamine. Phenoxide is a considerably better leaving group than ethoxide so that substitutions of phenyl 2,4,6-trinitrophenyl ethers and phenyl 2,4-dinitronaphthyl ether with aniline occur without the accumulation of intermediates. Both uncatalysed and base-catalysed pathways are involved. ... 

A study of the regioselectivity of the 1,3-dipolar cycloaddition of aliphatic nitrile oxides with cinnamic acid esters has been published. AMI MO studies on the gas-phase 1,3-dipolar cycloaddition of 1,2,4-triazepine and formonitrile oxide show that the mechanism leading to the most stable adduct is concerted. An ab initio study of the regiochemistry of 1,3-dipolar cycloadditions of diazomethane and formonitrile oxide with ethene, propene, and methyl vinyl ether has been presented. The 1,3-dipolar cycloaddition of mesitonitrile oxide with 4,7-phenanthroline yields both mono-and bis-adducts. Alkynyl(phenyl)iodonium triflates undergo 2 - - 3-cycloaddition with ethyl diazoacetate, Ai-f-butyl-a-phenyl nitrone and f-butyl nitrile oxide to produce substituted pyrroles, dihydroisoxazoles, and isoxazoles respectively." 2/3-Vinyl-franwoctahydro-l,3-benzoxazine (43) undergoes 1,3-dipolar cycloaddition with nitrile oxides with high diastereoselectivity (90% de) (Scheme IS)." " ... 

Phenyl-l,2,4-triazoline-3,5-dione has been prepared by oxidizing 4-phenylurazole with lead dioxide,7 and with ammoni-acal silver nitrate followed by an ethereal solution of iodine.8 The yields are low for both methods. 4-Substituted triazoline-diones can also be made by oxidation of the corresponding urazole with fuming nitric acid9 or dinitrogen tetroxide.10 Oxidation by <-butyl hypochlorite in acetone solution has also been described 1112 it, however, yields an unstable product, even after sublimation. Either dioxane12 or ethyl acetate are preferred as solvents for the reaction, since the product is obtained in a stable form. The latter solvent is superior since... 

Rate and equilibrium constants have been reported for the reactions of butylamine, pyrrolidine, and piperidine with trinitrobenzene, ethyl 2,4,6-trinitrophenyl ether, and phenyl 2,4,6-trinitrophenyl ether in acetonitrile, hi these reactions, leading to cr-adduct formation and/or nucleophilic substitution, proton transfer may be rate limiting. Comparisons with data obtained in DMSO show that, while equilibrium constants for adduct formation are lower in acetonitrile, rate constants for proton transfer are higher. This probably reflects the stronger hydrogen bonding between DMSO and NH+ protons in ammonium ions and in zwitterions.113 Reaction of 1,3,5-trinitrobenzene with indole-3-carboxylate ions in methanol has been shown to yield the re-complex (26), which is the likely precursor of nitrogen- and carbon-bonded cr-adducts expected from the reaction.114 There is evidence for the intermediacy of adducts similar to (27) from the reaction of methyl 3,5-dinitrobenzoate with l,8-diazabicyclo[5.4.0]undec-8-ene (DBU) cyclization eventually yields 2-aminoindole derivatives.115... 

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