4-hydroxyphenyl azide

The [3+2] cycloaddition reaction of 4-hydroxyphenyl azide with 2-ethynylpyridine affords the non-fluorescent cycloadduct 18, which displays turn-on fluorescence upon addition of Zn(OTf)2" . 

Azide ion will catalyze rearrangements of N- (aryloxy)pyridinium salts to give 3-(o-hydroxyphenyl)pyridines (Scheme 114). It is suggested that azide addition to the a-position... 

Bis( 1,1-dimethyl-2-propynyl)-peroxide. See under Acetylene Hydroperoxides A66-R Bis(hydroxylamino) Azide A525-L Bi s (hvdroxym ethyl )methyl aminomethane. See Aminomethylpropanediol A232-R 4-[Bi s(p-hydroxyphenyl)m ethylene]- 2,5-... 

H)-Oxazolones are formed by the spontaneous cyclization of /3-oxo isocyanates (equation 134). Similarly, o-hydroxyphenyl isocyanate, produced by the Curtius rearrangement of the azide of salicylic acid or by the action of sodium hypochlorite on salicylamide, forms benzoxazolone (equation 135). An analogous reaction is the formation of IV-phenyl-benzoxazolone by the action of thionyl chloride on the hydroxamic acid shown in equation (136) (78TL2325). Pyrolysis of aryl azidoformates affords benzoxazolones by nitrene insertion (equation 137) (81CC241). 

N- [2- ( 3,5-DI-tef -BUTYL-4-HYDROXYPHENYL ) ETHYL] N -(4-AZIDOSUL-fonylphenyl) urea (DTBSU). 4-Isocyanatobenzenesulfonyl azide (11.2 g, 0.05 mol) and dry acetonitrile (200 mL) were placed in a 500-mL three-necked flask fitted with a thermometer, stirrer, and drying tube. The flask was maintained at 20-25°C and 12.4 g (0.055 mol) of 2-(3.5-di-ter -butyl-4-hydroxyphenylethylamine (19) dissolved in 200 mL acetonitrile were added slowly. After 2 hr of stirring at room temperature ir spectrophotometric examination of an aliquot indicated complete loss of the isocyanate function. The acetonitrile was removed in a rotary evaporator and the remaining material poured into ice to precipitate the product in an 87% yield. The product melted at 122-127°C and evolved nitrogen at 140-150 °C. The ir spectrum contains bands at 3210 cm 1 (NH), 2120 cm 1 (azide), 1675 cm 1 (amide carbonyl), and 1160 cm 1 (sulf one). 

DI-f e/t-BUTYL-4-HYDROXYPHENYL ) PROPIONOXY] ETHYL 4-AZI-dosulfonylcarbanilate (DTBPSC). 3- (3,5-Di-terf-butyl-4-hydroxy-phenyl)propionyl chloride (20 g, 0.7 mol) (20) and 200 mL of dry DMF containing a few drops of pyridine were placed in a 500-mL flat-bottomed flask. The solution was stirred at room temperature as 21 g (0.7 mol) of 2-hydroxyethyl-4-azidosulfonylcarbanilate (15) dissolved in 150 mL of DMF were added. After stirring at room temperature, the DMF solution was poured into ice water and the solid was collected and dried to yield 22 g (58%) of product (mp 70-75°C). It decomposed at 175°C with evolution of nitrogen. The ir spectrum contained absorption bands at 3420 cm 1 (NH), 2120 cm 1 (azide), 1735 cm"1 (ester carbonyl), 1725 cm"1 (carbamate), and 1165 cm 1 (sulfone). 

The di(hydroxyphenyl)-1,2,4-triazole monomers are synthesized by reacting bis-(4-hydroxyphenyl)-hy dr azide with aniline hydrochloride at ca. 250 °C in the melt or by reacting 1,3 or l,4-bis-(4-hydroxyphenyl)-phenylene dihydrazide with 2 mol of aniline hydrochloride in the melt. The synthesis is shown in Figure 9.2. Purification of the di(hydroxyphenyl)-1,2,4-triazole monomers is accomplished by recrystallization. This synthetic route results in high-molecular-weight PTs. 

Preparation by reaction of sodium azide with 2-bromo-l-(2-hydroxyphenyl)ethanone (89%) [6141]. 

Preparation by reaction of sodinm azide with 2-bromo-1 -(3,5-di-tert-butyl-4-hydroxyphenyl) ethanone in dilnte acetone at r.t. for 1 h [6066]. 

Obtained by reaction of sodium azide with 4-[(4-propionyl-2-propyl-3-hydroxyphenyl)methoxy] benzene-acetonitrile in the presence of anunonium chloride in DMF at 105° for 20 h (32%) [7564]. 

Salicylhy dr azide see 2-Hydroxybenzoic acid [(2-hydroxyphenyl)methylene]hydrazide, H-00120 [18917-95-8]... 

Pyridine carboxylic acid [(2-hydroxyphenyl)methylene] hy dr azide, 9CI. N-Isonicotinoyl- N -salicylidene hydrazine. Salicylaldehyde isonicotinoylhydrazone. Acozid. Nicozid. Nilazid. Nupasal. o-Oxyberon. Phthiosan. Saliniazid. 

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