Phenol, <?-amino

It condenses with resorcinol and amino-phenols to give phthalein and rhodamine dyestuffs respectively. Esters are used in the formation of polyimides. ... 

Phenacetin may be conveniently prepared in the laboratory from p-amino-phenol. The latter is readily acetylated with acetic anhydride to give p-acetyl-aminophenol this Is ethylated in the form of the sodio derivative to yield acetyl p-phenetidine (phenacetin) ... 

Physostigmine can be regarded as the methylcarbamate of a -amino-phenol, with an alkyl chain substituent in the o-position, relative to the amino-group. Stevens and Beutel, with this in mind, have prepared substances of the type p-RjRjjN, CO, O. CgHjR. NMCjX, where R is an alkyl radical, c.gi, isopropyl, in either the o or m-positioQ relative to the... 

Nitro-pJienols and Nitro-acids dissolve in ctiustic alkahs as a rule with a deep yellow or orange colour. On reduction with st. innous chloride or zinc dust, as described above, they yield the amino-derivatives. In the case of the amino-phenol, the solution is made alkaline with caustic soda, satuiated with CO.j, salt added and extracted w ith ether. In the case of the amino-acid, the method used is that desciibed under Prep. 91 (p. 201). 

An interesting preparation of substituted o-aminophenols has been developed by Birkofer and Daum (30). 2-Acylfurans (8) plus an aliphatic secondary amine presumably condense to give the eorresponding enamine (9) (not isolated), which undergoes thermal isomerization to the o-amino-phenol (10). 

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

Picramic Acid. See under 4,6-Dimtro-2-amino-phenol in Vol 1, A241-R... 

Tylenol paracetamol N-acetyl-para-aminophenol para-acetyl-amino-phenol... 

Natriumboranat reduziert Nitroso-benzol in Athanol bei 30° zu Azoxybenzol (75% d.Th.), in Dimethyl-sulfoxid bei 85°zu Azobenzol (78% d.Th.)"1 und4-Nitroso-phenol, in Wasserbei 60°zu 4-Amino-phenol (42%... 

Die Bamberger-Umlagerung zu Amino-phenolen ist oft Ziel der elektrochemischen Reduktion, so z. B. bei der kathodischen Reduktion von 6-Chlor-2-nitro-toluol zu 2-Chlor-4-amino-3-methyl-phenol (an Pt bis 78% d.Th.)2 und von 2-Chlor-l-nitro-benzol zu 3-Chlor-4-amino-phenol (bis 63% d.Th.)3 (die leicht zu 1,4-Benzochinonen oxidiert werden konnen). 

Pyridin-l-oxid wird mit Hefe glatt zum Pyridin reduziert2. Aus Nitroso-benzolen wer-den mitHilfe vonHefen N-Phenyl-hydroxylamine bzw. Aniline4 (z. B.aus4-Nitro-so-phenol 40% d.Th. 4-Amino-phenol) erhalten. 

As in the case of benzimidazole, a parallel synthesis of benzoxazoles was described. The authors report that mixing directly differently substituted o-amino phenols 193 with acylating agents 194 and heating at 200 °C for 10-15 min under microwave irradiation, a collection of benzoxazoles 195 was obtained (Scheme 70). With this reaction, a 48-member library of benzoxazoles with different substituents on the aromatic rings was obtained [125]. 

For the synthesis of coumarins, the Pechmann reaction [145] is one of the most popular synthetic routes. As the reaction is conventionally carried out at high temperature, two microwave-assisted versions have been recently described. Besson and co-workers described the cyclocondensation of different m-amino phenols 226 with /1-ketoesters 227 on graphite/montmorillonite KIO support (Scheme 83). The use of graphite was crucial in the development of the reaction conditions. In fact, microwave irradiation of the reagents using different conditions gave poor results in terms of yields and purity. The optimized conditions, using a monomode microwave system, employed... 

CN 3-[[(4,5-dihydro-l/ /-imidazol-2-yl)methyl](4-methyIphenyl)amino]phenol monohydrochloridc... 

Aromatic amines, amino phenols [1] e.g. aromatic o-diamines [2]... 

This Compound is a benzoxazole with a disconnection to an ortho amino phenol (54) and an acid derivative. Further disconnections on (54) are straightforward. 

Most aromatic difunctional reagents react with N3P3Cl6 to afford spirocyclic products (20,176,180,181,189,190). With catechol, the trispiro product is observed (190). This product was shown to function as a host in the formation of several inclusion adducts, including polymers (191). Ring degradation of the cyclophosphazene ring occurs in the reaction with o-amino phenol as well as in the reaction with catechol in the presence of a triethylamine (192). 

The variety and extent of research devoted to ligands carrying both O- and N-donors is simply immense. The type of cobalt(III) systems extant include amino acids, amino alcohols, amino ethers, amino phosphates, amino phenolates, as well as amide and imine analogs of these. These are met as simple chelates or more elaborate polydentates. Here, we highlight a strictly limited selection of examples to illustrate the type of systems reported no attempt at exhaustive review has been made. 

The same laboratory has prepared three tridentate zinc chelates from chiral tertiary amino phenolic alcohols and used them for enantioselective addition of diethylzinc to aryl aldehydes in 70-87% ee. Results with the ligand 4 [from (1S,2S)-(+ )-pseudoephedrine] are typical. 

This is the best known rearrangement reaction of phenylhydroxylamines and is an acid catalysed reaction leading principally to the formation of 4-amino phenols 37, although a little of the 2-isomers 38 are also sometimes formed. Reaction proceeds quite smoothly in relatively dilute acid at room temperature. Reaction is quite general for a range of R and X substituents. Much of the early work was carried out by Bamberger38 and the position up to 1967 has been very well reviewed39. 

The rearrangement reaction continues to be of synthetic utility, often involved in industrial processes. Patent references (e.g. Reference 48) refer to the formation of 4-amino phenols. Often the reactant nitro compound is reduced (to the hydroxylamine) in an acid environment so that the two-stage reaction can be accomplished as a one-pot synthesis. 4-Amino phenol itself 45 can be made in high yield directly from nitrobenzene49 and the 4-methoxy aniline derivative 46 similarly from 2-methylnitrobenzene by hydrogenation in MeOH/H2S0450. 

The reactivity of MEC with amino-phenols, -benzylalcohols, -acids, and -benzamides (substrates of Scheme 4.9) is largely modified by the properties of aromatic substituents (X = OH, CO2H, CH2OH, CONH2). " Both steric and... 

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