Acetic hydroxyphenyl-,

Chemical off—on switching of the chemiluminescence of a 1,2-dioxetane (9-benzyhdene-10-methylacridan-l,2-dioxetane [66762-83-2] (9)) was first described in 1980 (33). No chemiluminescence was observed when excess acetic acid was added to (9) but chemiluminescence was recovered when triethylamine was added. The off—on switching was attributed to reversible protonation of the nitrogen lone pair and modulation of chemically induced electron-exchange luminescence (CIEEL). Base-induced decomposition of a 1,2-dioxetane of 2-phen5l-3-(4 -hydroxyphenyl)-l,4-dioxetane (10) by deprotonation of the phenoHc hydroxy group has also been described (34). 

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). 

A (4-Hydroxyphenyl)glycine. This derivative (23) forms aggregate spheres or shiny leaflets from water. It turns brown at 200°C, begins to melt at 220°C, and melts completely with decomposition at 245 —247°C. The compound is soluble in alkaU and mineral acid and sparingly soluble in water, glacial acetic acid, ethyl acetate, ethanol, diethyl ether, acetone, chloroform, and benzene. 

Sodium N-(1-methoxycarbonyl-1 -propen-2-yl)-D(-)-0 -amino-(4-hydroxyphenyl)acetate Ethyl chlorocarbonate... 

A) A mixture of 333 parts of 4-(1 -piperazinyDphenol dihydrobromide, 11.2 parts of acetic acid anhydride, 42 parts of potassium carbonate and 300 parts of 1,4-dioxane is stirred and refluxed for 3 days. The reaction mixture is filtered and the filtrate is evaporated. The solid residue is stirred in water and sodium hydrogen carbonate is added. The whole is stirred for 30 minutes. The precipitated product is filtered off and dissolved in a diluted hydrochloric acid solution. The solution is extracted with trichloromethane. The acid aqueous phase is separated and neutralized with ammonium hydroxide. The product is filtered off and crystallized from ethanol, yielding 5.7 parts of 1 acetyl-4-(4-hydroxyphenyl)piperazine MP 181.3°C. 

To a solution of 7 (d-p-hydroxyphenyl-0i-carboxyacetamido-7(l-methoxy-3-(1-methyl-tetrazol-5-vl)thiomethyl-1-oxadethia-3-cephem4-carboxylic acid (359 mg) in methanol (7 ml) is added a solution of sodium 2-ethylhexanoate in methanol (2 mols/liter 1.73 ml) at room temperature. After stirring for 10 minutes, the reaction mixture is diluted with ethyl acetate, stirred for 5 minutes, and filtered to collect separated solid, which is washed with ethyl acetate, and dried to give disodium salt of 7 (a-p-hydroxyphenyl-a-carboxyacetamido)-7Q -methoxy-3-(1-methyl-tetrazol-5-vl)thiomethyl-1-oxadethia-3-cephem4-carboxylic acid (342 mg). Yield 885%. Colorless powder. MP decomposition from 170°C. 

After 6 hours the calculated amount of hydrogen has been taken up. The residue obtained after filtering and evaporating is taken up in benzene and extracted twice with diluted sodium carbonate solution. The alkali extract is then made acid to Congo red with 6N hydrochloric acid and the precipitate is taken up in ethyl acetate. The solution obtained is washed twice with salt solution, dried with sodium sulfate and evaporated. The residue is recrystallized from ether/petroleum ether. 1-(p-hydroxyphenyl)-2-phenyl-4-n-butyl-3,5-dioxo-pyrazolidine melts at 124° to 125°C. 

Direct hydroxylation of an aromatic ring to yield a hydroxybenzene (a phenol) is difficult and rarely done in the laboratory., but occurs much more frequently in biological pathways. An example is the hydroxylation of p-hydroxyphenyl acetate to give 3,4-dihydroxyphenyl acetate. The reaction is catalyzed by p-hydroxyphenylacctate-3-hydroxylase and requires molecular oxygen plus the coenzyme reduced flavin adenine dinucleotide, abbreviated FADH2. 

Figure 16.6 MECHANISM Mechanism of the electrophilic hydroxylation of p-hydroxyphenyl acetate, by reaction with FAD hydroperoxide. The hydroxyiating species is an "0H+ equivalent that arises by protonation of FAD hydroperoxide, RO-OH + H+ — ROH -+ 0H+.

Discussion. Cadmium may be precipitated quantitatively in alkaline solution in the presence of tartrate by 2-(2-hydroxyphenyl)benzoxazole. The complex dissolves readily in glacial acetic acid, giving a solution with an orange tint and a bright blue fluorescence in ultraviolet light. The acetic (ethanoic) acid solution is used as a basis for the fluorimetric determination of cadmium.28... 

C15H21NO5) see Gusperimus trihydrochloride 4-[hydroxy[5-[[(phenylmethoxy)carhonyl]amino]pen-tyl]amino]-4-oxobutanoic acid (C,7H24N20ft 106410-46-2) see Deferoxamine D-a-(4-hydroxyphenyl)-tx-(2-methoxycarbonyl-l-methyl-cthenylamino)acetic acid anhydride with monoethyl carbonate... 

Bohman and Allenmark resolved a series of sulphoxide derivatives of unsaturated malonic acids of the general structure 228. The classical method of resolution via formation of diastereoisomeric salts with cinchonine and quinine has also been used by Kapovits and coworkers " to resolve sulphoxides 229, 230, 231 and 232 which are precursors of chiral sulphuranes. Miko/ajczyk and his coworkers achieved optical resolution of sulphoxide 233 by utilizing the phosphonic acid moiety for salt formation with quinine. The racemic sulphinylacetic acid 234, which has a second centre of chirality on the a-carbon atom, was resolved into pure diastereoisomers by Holmberg. Racemic 2-hydroxy- and 4-hydroxyphenyl alkyl sulphoxides were separated via the diastereoisomeric 2- or 4-(tetra-0-acetyl-D-glucopyranosyloxy)phenyl alkyl sulphoxides 235. The optically active sulphoxides were recovered from the isolated diastereoisomers 235 by deacetylation with base and cleavage of the acetal. Racemic 1,3-dithian-l-oxide 236... 

Figure 2. Linear regression plot of root growth inhibition of tomato and radish seedlings by o and -hydroxyphenyl) acids. o-Hydroxycinnamic acid, (o-hydroxyphenyl) acetic acid ( ) melilotic acid, 2-(o-hydroxyphenyl) butanoic acid ( ) o-hydroxy-benzoic acid, ( -hydroxypheny 1 )acetic acid (0) -hydroxycinnamic acid, =hydroxybenzoic acid, 3-( -hydroxyphenyl) propanoic acid (X) o-coumaryl glucoside, water control (----) (1 ). ...

Fig. 2 The effect of three phenolic acids on the Chi content of 2-week-old rice seedling. A. o-Hydroxyphenyl acetic acid B. ferulic acid and C. p-Coumaric acid. Kimura s culture solution contains 0, 25, 50, or 100 ppm of either o-hydroxyphenyl acetic, ferulic or p-coumaric acids. Extraction was done on liquid-nitrogen frozen leaves with 80% acetone. The data is mean of three determinations and the bars indicate the standard deviation (Yang et al. 2002, 2004).

Chemat et al. have reported several microwave reactors, including systems that can be used in tandem with other techniques such as sonication [68], and ultraviolet radiation [69]. With the microwave-ultrasound reactor, the esterification of acetic acid with n-propanol was studied along with the pyrolysis of urea. Improved results were claimed compared with those from conventional and microwave heating [68]. The efficacy of the microwave-UV reactor was demonstrated through the rearrangement of 2-benzoyloxyacetophenone to l-(2-hydroxyphenyl)-3-phenylpropan-l,3-dione [69]. 

Ar = 2-naphthyl. This ester is about 5 times less reactive than 2-naphthyl 2-hydroxyphenyl-acetate in 20% dioxan-water... 

FIGURE 1.7 Enantiomer separation of 2-(4-hydroxyphenyl)-imidazo[l,5-b]-quinazoline-1,5-dione on CHIRALPAK QN-AX under reversed conditions. CSP Chiralpak QN-AX (150 X 4 mm ID) mobile phase, 0.1 M ammonium acetate-methanol (60 40 v/v) pH = 6.0 ... 

The figure represents the chemical structure for paracetamol, which includes the N-(4-hydroxyphenyl) acetamide, derived from the interaction of p-aminophenol and an aqueous solution of acetic anhydride. The structure has two activating groups that make the benzene ring highly reactive toward electrophilic aromatic substitution. 

Highly enantioselective Mannich-type reactions of A-(2-hydroxyphenyl) aldi-mines with ketene trimethylsilyl acetals and of A-Boc-aldimines with acetyl acetone or furan are catalyzed by chiral phosphonic acids 9 derived from 3,3 -diaryl-(l )-BlNOL and POCI3 (Scheme 12.7). ... 

This enzyme [EC 1.14.13.3], also called p-hydroxyphenyl-acetate 3-hydroxylase, catalyzes the reaction of 4-hydroxy-phenylacetate with NADH and dioxygen to produce 3,4-dihydroxyphenylacetate, NAD", and water. FAD is used as a cofactor. 

Asymmetric reductive acetylation was also applicable to acetoxyphenyl ketones. In this case the substrate itself acts as an acyl donor. For example, m-acetoxyace-tophenone was transformed to (R)-l-(3-hydroxyphenyl)ethyl acetate under 1 atm H2 in 95% yield [16] (Scheme 1.12). The pathway of this reaction is rather complex. It was confirmed that nine catalytic steps are involved two steps for ruthenium-catalyzed reductions, two steps for ruthenium-catalyzed racemizations, two steps... 

The application of two of these inhibitors, N(O-hydroxyphenyl) sulfi-namoyl-tertiobutyl acetate and N(O-aminophenyl) sulfinamoyl-tertiobutyl acetate, to highly resistant wheat leaves infected with an avirulent strain of stem rust resulted in decreased lignification and decreased necrosis of penetrated host cells and concomitantly led to increased fungal development, occasionally even allowing some sporulation to occur (60). 

Dibenzofuran is highly stable to oxidizing agents. 2-Dibenzofuranol is oxidized to 2-(2-hydroxyphenyl)-l,4-benzoquinone by sodium periodate in aqueous acetic acid, whereas reaction of 1-dibenzofuranol or 4-dibenzo-furanols with Fremy s salt produces the dibenzofuran-l,4-quinones. The oxidation of dibenzofuran with microorganisms has been studied. A mutant strain of a Beijerinckia bacterium oxidizes dibenzofuran to a mixture of cis-2,3-dihydroxy-2,3-dihydrodibenzofuran and cis-l,2-dihy-droxy-l,2-dihydrodibenzofuran. The former compound was found to be too... 

If the anion of 2-(2 -hydroxyphenyl)-5(4/l/)-oxazolone 336 is used as a ligand, bis-chelate complexes 337 of copper(II), nickel(II), and zinc(II) have been prepared from the corresponding metal acetates. Alternatively, 336 and 2-(2 -aminophenyl)-5(4//)-oxazolone 340 can act as ligands with metals including palladium(II), platinum(II), ruthenium(II), nickel(II), and copper(II) to produce a variety of structurally diverse complexes 338, 339, and 341 as shown in Schemes 7.109 and 7.110. ° ... 

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