Amino ethers from phenols

The mem-dichlorobenzene complex reacts with protected 0-aryltyrosines to give aryl ethers. Both chlorine atoms can be sequentially substituted to give symmetrical or disymmetrical triaryl diethers (Scheme XVI). The building up of such diaryl ethers from phenolic compounds which have amino groups in their side chains... 

In the presence of a Mannich base, hydroxymethyl derivatives 268 may behave, in turn, as alcoholic reagents, thus affording amino group replacement with formation of the symmetrical ether 269 (R = R —CH ). Indeed, alcohols and phenols allow the synthesis of ethers 269, starting from phenolic Mannich bases as well as from the methiodides of aminomethylfcrrocenes, by reaction with alkoxide or phenoxide. Good results have been obtained with a thioporphirine Mannich base and zinc acetate. Esters 270 (Fig. 102) can be synthesized from various Mannich bases such as those derived from tropolones or purines, which are converted into acetoxymethyl... 

The introduction of amino groups into phenols and ethers can be accomplished by the formation and reductive cleavage of their azo compounds. The diazotizing agent may be prepared from sulfanilic acid, and the reduction can be performed with sodium hydrosulfite. Excellent examples are found in the synthesis of l-amino-2-naphthol (85%) and 4-amino-l-naphthol (75%). ... 

Complexes 2, 4-6, 8-10, and 13 promoted the t ROP of l-LA (Scheme 28.6, Table 28.3). Under the chosen conditions, the activity of complexes 4-6 supported by the LO amino-ether phenolate ligand decreased in the order Ca < Sr < Ba. This was linked to the increase of the nucleophilic reactivity of the L X Ae-OPLLA(Nu) species on descending from the least (Ca) to the most (Ba) electropositive metal. The catalysts based on 5 and 6 afforded moderate control over the parameters = 1.36-1.46) for the t ROP of 1000 equiv of l-LA, with turnover frequency (TOP) values of 2080 and... 

Gallagher et al. reported on various IV-heterocycle construction via cyclic sulfamides. Using this strategy, they synthesized enantiopure 1,4-benzoxazine 311, which was the precursor of the blockbuster antibiotic levolloxacin 312 (Scheme 40.67). Starting from Boc-protected amino alcohol 305, sulfamidate 306 was prepared using RuCU and NaI04. 306 was treated with halo phenol 308 followed by acidic hydrolysis to afford amino ether 310. The compound 310 underwent Pd-catalyzed C—N alkylative cyclization to produce benzoxazine 311, which was the potential precursor from which Levolloxacin 312 can be synthesized. 

The 1,3,4-oxadiazole 113 is formed from the azo compound 112 by the action of triphenylphosphine <96SL652>. A general synthesis of 1,3.4-oxadiazolines consists in boiling an acylhydrazone with an acid anhydride (e.g., Scheme 18) <95JHC1647>. 2-Alkoxy-2-amino-l,3,4-oxadiazolines are sources of alkoxy(amino)carbenes the spiro compound 114, for instance, decomposes in boiling benzene to nitrogen, acetone and the carbene 115, which was trapped as the phenyl ether 116 in the presence of phenol <96JA4214>. 

Of the substituted phenol ethers the amino-derivatives of anisole (anisidine) and phenetole (pkenetidine) may be mentioned. They are prepared from the nitrophenols by alkylation and subsequent reduction of the nitro-group. 

Phenolic compounds can be condensed forming aryl-aryl and aryl-oxygen-aryl (ether linkages) bonds to yield diaryl and diaryl ether polymers (59). These are in many ways similar to natural humic acids, confirming earlier research by others (60-62) that humic acids are formed from the copolymerization of phenolic compounds with amino acids, peptides, and amino sugars. 

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