Aromatic nucleophilic displacement

Polyetherification is similar to a polycondensation process formation of high molecular weight polymer requires precise adjustment of composition to approximately 1 1 ratio of bisphenol to dihalosulfone. Trace amounts of water gready reduce the molecular weight attainable owing to side reactions that unbalance the stoichiometry (76). The reactivity of the halosulfone is in the order expected for two-step nucleophilic aromatic displacement reactions ... 

F. Terrier, Nucleophilic Aromatic Displacement The Influence of the Nitro Group", VCH Publishers, New York (1991). 

Diuretic activity can be retained in the face of replacement of one of the sulfonamide groups by a carboxylic acid or amide. Reaction of the dichlorobenzoic acid, 174, with chlorsulfonic acid gives the sulfonyl chloride, 175 this is then converted to the amide (176). Reaction of that compound with furfuryl ine leads to nucleophilic aromatic displacement of the highly activated chlorine at the 2 position. There is thus obtained the very potent diuretic furosemide (177). ... 

Because of resonance stabilization of the anion, a tet-nazolyl moiety is often employed successfully as a bioisosteric replacement for a carboxy group. An example in this subclass is provided by azosemide (27). Benzonitrile analogue is prepared by phosphorus oxychloride dehydration of the corresponding benzamide. Next, a nucleophilic aromatic displacement reaction of the fluorine atom leads to The synthesis concludes with the 1,3-dipolar addition of azide to the nitrile liinction to produce the diuretic azosemi de (27). ... 

Norfloxacin (41), the substance which triggered this avalanche of activity, has recently been introduced into clinical practice in the United States. Its synthesis parallels closely that of its N-methyl analogue, pefloxacin, except that the nucleophilic aromatic displacement reaction of 32 is carried out with mono-N-carboethoxypiperazine instead and the final step encompasses deblocking of this carbamoyl ester moiety [8]. 

Interestingly, a substance somewhat closely related to flunixin, triflocin (30), is a diuretic rather than an antiinflammatory agent. It can be prepared by nucleophilic aromatic displacement on 4-chloronicotinic acid (29) with m-trifluoromethyl-aniline.8... 

Azaperone (128) is yet another of the tranquilizers related to haloperidol. Nucleophilic aromatic displacement of 2-chloropyridine by piperazine leads to amine 126 which is then alkylated in turn by 4-chloro-p-fluorobuterophenone (127) to give... 

Terrier, F. Nucleophilic Aromatic Displacement, Verlag Chemie, Weinheim, 1991. 

Hexafluoroisopropylidene-unit-containing aromatic poly(ether ketone)s were first synthesized from an alkaline metal salt of Bisphenol AF (1) and 4,4 -difluoro-benzophenone.14 Cassidy and co-workers prepared hexafluoroisopropylidene-unit-containing poly(ether ketone)s by condensing 2,2-bis[4-(4-fluorobenzoyl)-phenyl]-l,l,l,3,3,3-hexafluoropropane (9) and 2,2-bis[4-(4-fluorobenzoyl)-phenyljpropane (10) with Bisphenol AF (1) or Bisphenol A (4) (Scheme 7).15 The reactions are nucleophilic aromatic displacements and were conducted in DMAc at 155- 160°C with an excess of anhydrous potassium carbonate. After 3 to 6 h of reaction, high-molecular-weight poly(ketone)s are obtained in high yields. 

Table II. Phase Transfer Catalyzed Nucleophilic Aromatic Displacement Reactions ...

F. Terrier, in Nucleophilic Aromatic Displacement The Influence of the Nitro Group (H. Feuer, ed.), p. 257. Org. Nitro Chem. Ser., VCH Publishers, New York, 1991. 

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