1 - -m-aminophenol

Functional amines, e.g., m-aminophenol, 2-methyl-2-chloro-3-aminophenol, and 4-chloro-3-aminophenol, react with 4-methoxybut-3-en-2-one to yield functional lepidine derivatives 230 (62AG161). 

To determine the direction of primary attack at aminobutynones in the presence of competing hydroxyl and amino groups in the benzene ring, the reaction of 4-dimethylaminobut-3-yn-2-one with m-aminophenol has been examined (65-70°C, THF, 20 min). It was found that the hydroxyl group reacts first to form (9,A-ketenacetal of 4-dimethylamino-4-(m-aminophenoxy)-but-3-en-2-one (363) (88ZOR1165). 

Most of the important class of coumarins used as polyester FBAs are made via 7-amino-3-phenylcoumarin (11.46), which can be prepared by the Pechmann procedure from m-aminophenol. Conversion of intermediate 11.46 to FBAs may be achieved in various ways, two of which are shown in Scheme 11.13. 

Efficient synthesis of 7-aminocoumarins has been performed via the Pechmann reaction between m-aminophenols and /i-ketonic esters. A comparative study of this procedure showed that use of microwave irradiation reduced the reaction time from several hours, if conventional heating was used, to a few minutes only (Eq. 22) [75]. 

Spectrophotometric determination with 4-hexylresorcinol and a fluorometric method with m-aminophenol are the most commonly used procedures for the determination of acrolein. However, gas chromatography and high-performance liquid chromatography procedures are also used (USEPA 1980 Kissel etal. 1981 Nishikawa and Hayakawa 1986). Acrolein concentrations in rainwater between 4 and 200 pg/L can be measured rapidly (less than 80 min) without interference from related compounds the method involves acrolein bromination and analysis by gas chromatography with electron capture detection (Nishikawa and Hayakawa 1986). Kissel etal. (1981) emphasize that water samples from potential acrolein treatment systems require the use of water from that system in preparing blanks, controls, and standards and that acrolein measurements should be made at the anticipated use concentrations. 

The most magnificent dyes, which are chiefly used in the dyeing of silk, are relatives of eosin obtained from di- and tetra-chlorophthalic anhydride (phloxine, rose bengale). The (basic) rhodamines also belong to this class. They are produced by condensation of phthalic anhydride with m-aminophenols (in place of resorcinol) the dye containing the diethylated NH2-group, in particular, is of great technical importance. 

The pKa value of m-aminophenol is about 10.0 (water, 25 °C), i.e. very close to that of phenol itself, in accord with the very small electronic effect of m-NH2, as discussed above. For p-aminophenol the pKa value is about 10.4, corresponding to an apparent a value of about —0.2. This is very close to the cr° value indicated above, as might be expected. 

DNB included m-nitrophenol, m-aminophenol, resorcinol, fumaricacid, and some volatile fatty acids (Dey and Godbole 1986). A pure culture of Rhodococcus sp. isolated from soils contaminated with nitroaromatics was capable of using 1,3-DNB as a sole source of nitrogen. This culture metabolized 1,3-DNB to nitrite via a 4-nitrocatechol pathway even in the presence of high amounts of ammonia (Dickel and Knackmuss 1991). 

Typical primary amines which undergo such nitrosation are m-toluidine, p-xylidine, m-anisidine, 2-amino-4-methoxytoluene, 3-amino-4-methoxy-toluene, m-aminophenol, a-naphthylamine, l-naphthylamine-2-, -6-, -7-, and -8-monosulfonic acids, and l-naphthylamine-4-monosulfonic acid (which reacts with displacement of the sulfonic acid group). The secondary amines derived from these primary amines also can be nitrosated directly (i.e., without the intermediate formation of an JV-nitroso compound which needs to be subjected to the Fischer-Hepp rearrangement). The entering nitroso group appears to substitute exclusively in the para position. 

An interesting approach to maleimide-terminated phenoxy resin has recently has described (42). para-Maleimidobenzoic acid was reacted with diglyci-dylbisphenol-A epoxy resin in the presence of catalyst to provide the bismale-imide of Fig. 13. Instead of diglycidyl bisphenol-A, linear epoxy resin pre-polymers can be used in this reaction to form a maleimide terminated phenoxy resin. Another suitable functionalized monomaleimide is m- or p- N-(hydroxyphenyl) maleimide which is synthesized from maleic anhydride and m-aminophenol in DMF as a solvent at 70 °C. The purified hydroxyphenyl maleimide was reacted with epoxy resin to form novel BMIs as outlined in Fig. 14. The new BMI and phenoxy oligomers polymerize at temperatures of 200-220 °C, but the cure temperatures can be significantly lowered when catalysts such as imidazoles or triphenylphosphine are added. The cured homopolymers show Tg of 140 and 230 °C for the n = 2 and the n = 1 polymer, respectively(43). 

The Michael addition reaction has attracted many researchers as a route to convert high melting BMI building blocks into resins with improved processability as compared with the BMI building blocks. Heat resistant resin compositions have been prepared from para- or meta-aminophenol (52). The idealized structure of such a BMI/m-aminophenol adduct is shown in Fig. 19. 

A nitro group at the meta position is readily hydrolysed in water to the phenolic group with the formation of the nitro derivative of N-methyl-m-aminophenol (VIII). Since technical dimethylaniline usually contains a certain amount of methylaniline,... 

The most important FBAs in the coumarin series are the 7-amino-3-phenylcoumarins which are prepared via the Pechmann coumarin synthesis. For example, m-aminophenol may be condensed with ethyl 3-hydroxy-2-phenylacrylate in the presence of a Lewis acid in nitrobenzene (Scheme 13). 

Unsymmetrical rhodamines can be prepared by the condensations of one mole of a m-aminophenol with phthalic anhydride to give an 0-benzoyl benzoic acid (27) which is then further condensed with a different m-aminophenol to give the required product, Rhodamine 3GO (28) (2). A general route to asymmetrical acid xanthenes has been patented (39). 

Aminophenol, AH19 m-Aminophenol, AH20 -Aminophenol, AH21... 

Whereas the Ti linker involves an immobilization of a diazonium salt on an amine resin, the T2 linker represents the reversal of this concept. As outlined in Scheme 10, m-aminophenol (54) was attached to Merrifield resin 53 by displacing the chloride group via the phenolic group with the aid of sodium hydride in dimethylformamide (DMF) (see Experimental... 

Method B Sample was oxidized with chloramine T, reacted with m-aminophenol and the absorbance was measured at 420 nm. 

Pumera et al. [34] used gold nanoparticle enhanced open channel NCEC for the separation of p-aminophenol, o-aminophenol, and m-aminophenol in a bare glass channel and polydiallyl dimethyl ammonium chloride (PDADMAC) gold coated channel. The mobile phase used was acetate buffer (20 mM, pH 5.0) with electrokinetic sample injection at 1.5kV/cm for 3 seconds and 2.0kV/cm as separation voltage (Fig. 7.15). Broyles... 

Figure 7.15 Chromatogram of the separation of (1) /j-aminophcnol, (2) o-aminophenol, and (3) m-aminophenol, (A) without treatment and (B) after PDADMAC gold coating chips [34].

In alkaline medium m-aminophenol couples at the position para to the hydroxyl group in an acid solution /i-hydroxy and / -aminoazo dyes are obtained. 

As described in US Patent 427,564, aminosalicylic acid may be prepared from m-aminophenol by heating with ammonium carbonate in solution under pressure. 

Alkoxyl Groups. Simple alkoxyl substituted phenylarsonic acids may be synthesized from the corresponding amines without difficulty, o-Methoxyphenylarsonic acid may be prepared in 58% yield, and a nearly quantitative yield of p-ethoxyphenylarsonic acid is obtained from p-phenetidine.14 The favorable influence of a p-alkoxyl group is further illustrated by the preparation of 3-hydroxy-4-methoxyphenylarsonic acid in a 26% yield.89 As previously mentioned, ra-hydroxyphenylar-sonic acid could not be prepared from m-aminophenol o- and m-j3-hy-... 

Peaks l=hypoxanthine 2=m-aminophenol 3=inosine. (b) Hypoxanthine peak for various phosphate concentrations in mg L 1 (indicated above each peak)... 

Pyridine, 2-methylpyridine, pyrimidine, pyrrole, imidazole, indole, and purine are aromatic. 19.3. (a) pentan-2-amine (b) A-methylbutan-2-amine (c) m-aminophenol (d) 3-methylpyrrole (e) /ram-cyclopentane -1,2-diamine (f) c -3-aminocyclohexanecarbaldehyde. 19.4. (a) resolvable (chiral carbons) (b) not resolvable (N inverts) (c) symmetric ... 

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