Alkali phenoxide

Sodium 4-methylphenoxide solution was dehydrated azeotropically with chlorobenzene, and the filtered solid was dried in an oven, where it soon ignited and glowed locally. This continued for 30 min after it was removed from the oven. A substituted potassium phenoxide, prepared differently, also ignited on heating. Finely divided and moist alkali phenoxides may be prone to vigorous oxidation (or perhaps reaction with carbon dioxide) when heated in air. 

Scheme 5.1 Formation of salicylic acid from alkali phenoxides and C02 under pressure.

Scheme 5.5 Carboxylation of C-H-active substrates with alkali phenoxides and C02 [33],...

In the preparation of substituted diaryl ethers (ArOAr ), the reaction of alkali phenoxides and aryl halides is catalyzed by copper (Ullmann). Further studies have shown that the yield varies considerably with different copper-catalyst preparations. ... 

Metalation of calix[4]arene with NbClj and TaClj produces metal complexes which, when treated with alkali phenoxides, entrap the alkali metal ions within the calix, as indicated by X-ray crystallography Zanotti-Gerosa, A. Solari, E. Giannini, L. Floriani, C. Chiesi-Villa, A. Rizzoli, C. J. Chem. Soc., Chem. Commun. 1997, 183. 

A number of compounds of the types RBiY2 or R2BiY, where Y is an anionic group other than halogen, have been prepared by the reaction of a dihalo- or halobismuthine with a lithium, sodium, potassium, ammonium, silver, or lead alkoxide (120,121), amide (122,123), a2ide (124,125), carboxylate (121,126), cyanide (125,127), dithiocarbamate (128,129), mercaptide (130,131), nitrate (108), phenoxide (120), selenocyanate (125), silanolate (132), thiocyanate (125,127), or xanthate (133). Dialkyl- and diaryUialobismuthines can also be readily converted to secondary bismuthides by treatment with an alkali metal (50,105,134) ... 

Hydroxybenzoic acid has been prepared by heating potassium phenoxide in a stream of carbon dioxide or with carbon tetrachloride, and by heating jfr-cresol with alkalies and various metallic oxides. The procedure described above is similar to one which appears in the early literature ... 

For the classical Williamson synthesis an alcohol is initially reacted with sodium or potassium to give an alkoxide, e.g. 1. Alternatively an alkali hydroxide or amide may be used to deprotonate the alcohol. Phenols are more acidic, and can be converted to phenoxides by treatment with an alkali hydroxide or with potassium carbonate in acetone. ... 

Condensation of an activated aromatic halide witli eitlier an alkali metal tliio-phenoxide or an alkali metal sulfide is performed under the same experimental condensations as used for polyetherification (Scheme 6.33).248... 

Alkali metal (haloarylsulfonyl)thio-phenoxides, 364 Alkaline hydrolysis of nylon-6,6, 568-569 of PET, 549-550 Alkyd resins, 18, 30-31, 59-60 synthesis and cure of, 102 Alkylphenolic resins, 376 Alkylphenols, 376, 400 Allophanates, 227... 

Finally,- the alkali salts of phenol itself are more deeply coloured than is phenol. This fact cannot indeed be recognised subjectively, but investigation of the absorption of ultra-violet light demonstrates it. Thus it has been found that the absorption by sodium phenoxide much more nearly approaches the subjectively visible part of the spectrum than does that of the free phenol. The difference is so considerable that it provides also a satisfactory explanation of a subjectively perceptible deepening of colour from colourless to yellow. The colour of the salts of nitrophenols is therefore ascribed to the bathychromic (colour-deepening) efEect of salt-formation. 

Although there have been few new developments in the period since 1993, halogenopyrazines 42 have been convenient precursors for a variety of pyrazine derivatives. For example, the halogenopyrazines 42 are cyanated by palladium-catalyzed cross-coupling with alkali cyanide or by treatment with copper cyanide in refluxing picoline, to yield cyanopyrazines 48. Alkoxypyrazines 49 are produced by treatment with alkoxide-alcohol, and aminopyrazines 50 are prepared by amination with ammonia or appropriate amines. The nucleophilic substitution of chloropyrazine with sodium alkoxide, phenoxide, alkyl- or arylthiolate is efficiently effected under focused microwave irradiation <2002T887>. 

Other methods of preparing flavone include the action of ethanolic alkali on 2 -acetoxy-a,/3-dibromochalcone 7 Claisen condensation of ethyl o-ethoxybenzoate and acetophenone, and cyclization of the resulting 1,3-diketone with hydriodic acid 8 and treatment of 3-bromoflavanone with potassium hydroxide in ethanol.9 Flavone has also been prepared from ethyl phenyl-propiolate by condensation with sodium phenoxide and subsequent cyclization with phosphorus pentachloride in benzene 10 by fusing o-hydroxyacetophenone with benzoic anhydride and sodium benzoate 11 by the dehydrogenation of 2 -hydroxychal-cone with selenium dioxide 12 and by the action of alkali on flavylium chloride.13... 

Williams225 has recently reported the synthesis of etherimides by treating halogeno- or nitroamides (152) with alkali metal phenoxides (153) in a nonpolar organic solvent in the presence of a phase transfer catalyst. 

---