Ethyl 2-nitrophenyl

In the catalytic hydrogenation of ethyl 2-nitrophenyl acetate (43), Di Carlo observed a small amount of the cyclic hydroxamic acid (44) in addition to the expected lactam (45). Following this result, a... 

Appropriate 5-substituted 2-nitrophenols have been transformed by acylation with chloroformylformate into (substituted) ethyl 2-nitrophenyl oxalates as extremely reactive building blocks for the synthesis of the 2,3-dioxo-l,4-benzoxazine skeleton [115]. Due to their extreme sensitivity towards hydrolysis water has to be excluded on reductive cyclisation of these nitrophenyl esters. 

Benzisoxazoles could be obtained by cyclization reactions forming N—O, O—C(7), or N—C(3) bonds as well as by heterocyclic rearrangements <84CHEC-I(6)l>. 1,2-Benzisoxazole (313) is synthesized from lithiated 3,5-dimethyl isoxazole (312) and a-oxoketene (311) (Equation (62)) <88TL50I>. Thermal transformations of ethyl nitrophenyl ethanoates (314) resulted in cyclization, to afford 2,1-benzisoxazole (316) via the ketene intermediate (315). Its mechanism has been discussed with evidence <95CC2457>. 

Synonyms ENT 17798 EPN 300 Ethoxy-4-nitrophenoxy phenylphosphine sulfide Ethyl j9-nitrophenyl benzenethionophosphate Ethyl / -nitrophenyl benzenethiophosphonate Ethyl j9-nitrophenyl ester 0-Ethyl O-4-nitrophenyl phenylphosphonothioate Ethyl p-nitrophenyl phenylphosphonothioate 0-Ethyl 0-p-nitrophenyl phenylphosphonothioate Ethylj9-nitrophenyl thionobenzenephosphate Ethyl/ -nitrophenyl thionobenzenephospho-nate 0-Ethyl phenyl />-nitro-phenyl phenylphosphorothioate 0-Ethyl phenyl />-nitrophe-nyl thiophosphonate Phenylphosphonothioic acid 0-ethyl 0-/>-nitrophenyl ester Phosphonothioic acid 0,0-diethyl 0-(3,5,6-trichloro-2-pyridinyl) ester Pin Santox. 

The kinetics of the basic hydrolysis of ethyl / -nitrophenyl ethylphosphonate (190) in the SDS-hexanol-water reverse micellar system has shown that at high pH and low water content the reaction occurs in the surface layer and is adequately described by a pseudo-phase model.The reactivity of ethyl aryl chloromethylphosphonates (191 X = NO2, Br, H, Et, Bu, n-octyl) in the basic hydrolysis reactions in direct micelles of cetyltrimethylammonium bromide depends on both the electronic and the hydrophobic... 

One route to o-nitrobenzyl ketones is by acylation of carbon nucleophiles by o-nitrophenylacetyl chloride. This reaction has been applied to such nucleophiles as diethyl malonatc[l], methyl acetoacetate[2], Meldrum s acid[3] and enamines[4]. The procedure given below for ethyl indole-2-acetate is a good example of this methodology. Acylation of u-nitrobenzyl anions, as illustrated by the reaction with diethyl oxalate in the classic Reissert procedure for preparing indolc-2-carboxylate esters[5], is another route to o-nitrobenzyl ketones. The o-nitrophenyl enamines generated in the first step of the Leimgruber-Batcho synthesis (see Section 2.1) are also potential substrates for C-acylation[6,7], Deformylation and reduction leads to 2-sub-stituted indoles. 

Intermediates benzene to ethyl phenyl ketone to ethyl m nitrophenyl ketone to m aminophenyl ethyl ketone to ethyl m fluorophenyl ketone Reagents propanoyl chloride AICI3 HNO3 H2SO4 Fe HCl then HO NaN02 H2O HCl then HBF4 then heat... 

Acylation. Reaction conditions employed to acylate an aminophenol (using acetic anhydride in alkaU or pyridine, acetyl chloride and pyridine in toluene, or ketene in ethanol) usually lead to involvement of the amino function. If an excess of reagent is used, however, especially with 2-aminophenol, 0,A/-diacylated products are formed. Aminophenol carboxylates (0-acylated aminophenols) normally are prepared by the reduction of the corresponding nitrophenyl carboxylates, which is of particular importance with the 4-aminophenol derivatives. A migration of the acyl group from the O to the N position is known to occur for some 2- and 4-aminophenol acylated products. Whereas ethyl 4-aminophenyl carbonate is relatively stable in dilute acid, the 2-derivative has been shown to rearrange slowly to give ethyl 2-hydroxyphenyl carbamate [35580-89-3] (26). 

Reaction of carboxylate ion with nitrophenyl sulfites gives the carboxylate -nitrophenyl esters. If the -nitrophenyl sulfite is unsymmethcal (02NCgH40S(0)0R, where R is ethyl or phenyl), carboxylate attacks the -nitrophenyl side (69). Some amino acids react with methyl and benzyl sulfites in the presence of -toluenesulfonic acid to give methyl and benzyl esters of the amino acids as -toluenesulfonate salts (70). With alcohols, the conversion of henzil to a monoacetal upon addition of sulfuric acid to the henzil in methanol and dimethyl sulfite proceeds in high yield (71). 

Imidazole, 2-ethyl-1 -(o-nitrophenyl)-cyclization, S, 431 Imidazole, 4-ethyl-2-phenyl-oxidation, S, 405 Imidazole, ethynyl-Michael addition, S, 437 Imidazole, 4-ethynyl-2-phenyl-synthesis, S, 494 Imidazole, 1-formyl-reactions, S, 452 Imidazole, 2-formyl-mass spectra, S, 360 Imidazole, 4-formyl-synthesis, S, 475-476 Imidazole, 2-formyl-1,5-dimethyl-mass spectra, S, 360 3-oxide... 

The Teoc group is introduced onto pyrroles, or indoles with 4-nitrophenyl 2-(tri-methylsilyl)ethyl carbonate and NaH in 61-64% yield. The Teoc group can be removed with Bu4N F in CH3CN. ... 

Ethyl chrysanthemate (ethyl 2,2-dimethyl-3 c and t -[2-methylpropenyl]-cyclopropane carboxylate) [97-41-6] M 196.3, b 98-102 /llmm, 117-121 /20mm. Purified by vacuum distn. The free trans-acid has m 54° (from, EtOAc) and the free cis-acid has m 113-116° (from EtOAc). The 4-nitrophenyl ester has m 44-45° (from pet ether) [Campbell and Harper J Chem Soc 283 1945 IR Allen et al. JOrg Chem 21 29 1957]. 

The described method of preparation of w-nitrophenyl disulfide is essentially that of Foss and co-workers and is a modification of that reported by Ekbom. The disulfide has been prepared by reaction of potassium ethyl xanthate with w-nitrobenzenedi-azonium chloride solution, followed by hydrolysis to yield the mercaptan, which is subsequently oxidized with potassium ferro-cyanide or dilute nitric acid to the disulfide. ... 

Enantiomerically pure dipeptide is obtained when the /7-nitrophenyl ester of N-henzoyl-L-leueine is coupled with glycine ethyl ester in ethyl acetate ... 

If, however, the /7-nitrophenyl ester of iV-henzoyl-L-leucine is treated with 1-methyl-piperidine in chloroform for 30 min and then coupled with glycine ethyl ester, the dipeptide isolated is almost completely racemic. Furthermore, treatment of the p-nitrophenyl ester of iV-benzoyl-L-leucine with 1-methylpiperidine alone leads to the formation of a crystalline material, C13H15NO2, having strong IR bands at 1832 and 1664 cm . Explain these observations, and suggest a reasonable stmcture for the crystalline product. 

Kinetics of the reaction of p-nitrochlorobenzene with the sodium enolate of ethyl cyanoacetate are consistent with this mechanism. Also, radical scavengers have no effect on the reaction, contrary to what would be expected for a chain mechanism in which aryl radicals would need to encounter the enolate in a propagation step. The reactant, /i-nitrophenyl chloride, however, is one which might also react by the addition-elimination mechanism, and the postulated mechanism is essentially the stepwise electron-transfer version of this mechanism. The issue then becomes the question of whether the postulated radical pair is a distinct intermediate. 

Chemical Designations - Synonyms 0,0-Diethyl 0-(p-nitrophenyl) phoshorothioate 0,0-Diethyl O-(p-nitrophenyl) thiophosphate Ethyl Parathion Phosphoroiioic acid 0,0-diethyl 0-p-nitrophenyl... 

In the second major method of peptide synthesis the carboxyl group is activated by converting it to an active ester, usually a p-nitrophenyl ester. Recall from Section 20.12 that esters react with ammonia and amines to give fflnides. p-Nitrophenyl esters are much more reactive than methyl and ethyl esters in these reactions because p-nitrophenoxide is a better (less basic) leaving group than methoxide and ethoxide. Simply allowing the active ester and a C-protected amino acid to stand in a suitable solvent is sufficient to bring about peptide bond formation by nucleophilic acyl substitution. 

Remove the Z protecting group from the ethyl ester of Z-Phe-Gly by hydrogenolysis. Couple with the p-nitrophenyl ester of Z-Leu then remove the Z group of the ethyl ester of Z-Leu-Phe-Gly. 

DBU, CH3CN, 140 s. The 2-(4-nitrophenyl)ethyl (Npe) phosphate protective group and the 2-(4-nitrophenyl)ethoxycarbonyl (Npeoc) group are stable to these conditions, but the cyanoethyl group is not. 

Nitrophenyl)ethyl]sulfonate (Npes-OR) 4-NO2C6H4CH2CH2SO3R Formation... 

An 5-(l-m-nitrophenyl-2-benzoyl)ethyl thioether was used to protect thio-phenols during electrophilic substitution reactions of the benzene ring. ... 

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