847872-05-3Relevant academic research and scientific papers
Activation of chlorine and fluorine by a phenylazo group towards nucleophilic aromatic substitution. Regioselective preparation of polysubstituted anilines
Fryszkowska, Anna,Tilford, Robert W.,Guo, Fengli,Kaszynski, Piotr
, p. 2327 - 2333 (2005)
A phenylazo group was used for selective activation of ortho fluorine and chlorine atoms towards nucleophilic aromatic substitution with the propanethiolate anion. This enabled a regioselective synthesis of three substituted 4-alkoxyanilines. The regioselectivity of substitution was confirmed by comparison of experimental NMR chemical shifts with empirically predicted values. The observed reactivity of the substrates is discussed in the context of the substituent effect.
Process for the preparation of halogen containing 4-amino phenols
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Page/Page column 9, (2010/02/11)
Production of 4-aminophenol derivatives (I) comprises converting an aniline (II) to a diazonium salt (III), reacting (III) with a phenol (IV) in the presence of a base to give a phenylazophenol (V), and reacting (V) with a reducing agent and optionally O-alkylating the product. Production of 4-aminophenol derivatives of formula (I) comprises converting an aniline of formula (II) to a diazonium salt of formula (III), reacting (III) with a phenol of formula (IV) in the presence of a base to give a phenylazophenol of formula (V), and reacting (V) with a reducing agent and optionally O-alkylating the product: [Image] m : 0-3; n : 1-4; m+n : 4 or less; R 1>H, 1-12C alkyl or 5-15C aralkyl; R 2>1-12C fluoroalkyl, 1-12C fluoroalkylthio or 1-12C fluoroalkoxy; Hal : Br, Cl or F; R 3>halo, CN, SCN, SO 3M, NO 2, 1-12C alkyl, 1-12C fluoroalkyl, 1-12C fluoroalkylthio,1-12C fluoroalkoxy, 1-12C alkoxy, 1-12C alkoxycarbonyl, di(1-12C alkyl)amino, 4-14C aryl or 5-15C aralkyl; M : H or alkali metal; p : 0-3; An : an anion. Independent claims are also included for: (1) compounds (I) other than 4-amino-3,5-difluorophenol, 4-amino-2,5-difluorophenol, 4-amino-2,6-difluorophenol, 4-amino-2-chloro-6-fluorophenol, 4-amino-2-chloro-3-fluorophenol, 4-amino-2-chloro-5-fluorophenol, 4-amino-2-bromo-5-fluorophenol, 4-amino-2-fluorophenol, 4-amino-3-fluorophenol, 4-amino-5-chloro-2-(trifluoromethyl)phenol, 4-amino-2-chloro-6-(trifluoromethyl)phenol and (it is stated) 4-amino-2-(trifluoromethyl)phenol and 4-amino-3-(trifluoromethyl)phenol; compounds (V) other than 3,5-difluoro-4-phenylazo-phenol, 3-fluoro-4-phenylazophenol, 3-fluoro-4-(4'-nitrophenylazo)-phenol, 3-fluoro-4-(3'-nitrophenylazo)-phenol, 3-fluoro-4-(4'-thiocyanatophenylazo)-phenol, 3-fluoro-4-(4'-sulfophenylazo)-phenol, 4-(2'-fluoro-4'-hydroxyphenylazo)benzoic acid ethyl ester, 2-fluoro-4-(4'-fluorophenylazo)-phenol, 2-fluoro-4-(3'-fluorophenylazo)-phenol, 2-fluoro-4-(4'-sulfophenylazo)-phenol, 4-(3'-fluoro-4'-hydroxyphenylazo)benzoic acid ethyl ester, 2,3-difluoro-4-(4'-iodphenylazo)-phenol; 2,3-difluoro-4-(4'sulfophenylazo)-phenol, 2,6-difluoro-4-(2'-bromphenylazo)-phenol and (it is stated) 3-(trifluoromethyl)-4-(phenylazo)-phenol and 3-(trifluoromethyl)-4-(4'-sodiumsulfonatophenylazo)-phenol.
