Sodium ethoxide, reaction with

Esters of dicarboxyUc acids having hydrogen on tbe 8 or e carbon atoms undergo intramolecular cyclisation when heated with sodium or with sodium ethoxide. This cyclisation is known as the Dieckmann reaction. It is essentially an application of the Claiseu (or acetoacetic eater) condensation to the formation of a ring system the condensation occurs internally to produce s... 

The condensation of aldehydes and ketones with succinic esters in the presence of sodium ethoxide is known as the Stobbe condensation. The reaction with sodium ethoxide is comparatively slow and a httlo reduction of the ketonic compound to the carbinol usually occurs a shorter reaction time and a better yield is generally obtained with the more powerful condensing agent potassium ieri.-butoxide or with sodium hydride. Thus benzophenone condenses with diethyl succinate in the presence of potassium [Pg.919]

Sodium ethoxide is prepared by the reaction of sodium metal with ethanol... 

Pyrroles may be ring-expanded to pyridines in reactions having a greater academic than practical interest. Treatment of pyrrole with chloroform and sodium ethoxide (in effect, with dichlorocarbene, CCl2) gives a low yield of 3-chloropyridine [626-60-8]. A much better yield (33%) is obtained if chloroform and pyrrole are heated together in the vapor phase at 550°C some 2-chloropyridine (17) is also formed (71). 

Dichloropyridazine 1-Oxide produces both isomers with alkoxides. However, the ratio is dependent on the size of the alkoxy group. In the reaction with sodium methoxide 80% of 6-chloro-3-methoxypyridazine 1-oxide and 7.5% of 3-chloro-6-methoxypyridazine 1-oxide are formed. Similar results are also obtained with sodium ethoxide, while sodium propoxide affords only 6-chloro-3-propoxypyridazine 1-oxide. Amines react similarly, while only chlorine at the 3-position can be substituted with an azido group to give 3-azido-6-chloropyridazine 1-oxide. 

Using a slightly different ketene acetal 77, reaction with 76 and exposure to sodium ethoxide generated 78. This served as a precursor to 72. 

The thenyl cyanides are of great importance for the preparation of thiophene derivatives. Because of the acidifying effects of both the thienyl and of the cyano groups, carbanions are easily obtained through the reaction with sodamide or sodium ethoxide, which can be alkylated with halides, carbethoxylated with ethyl carbonate, or acylated by Claisen condensation with ethyl... 

Mono-substitution occurs most readily in the stepwise replacement of the halogen substituents of 2,4,6-trichloro-s-triazine with aqueous methanol and sodium bicarbonate (30°, 30 min), the monomethoxy derivative (324) is obtained on heating (65°, 30 min), the disubstitu-ted derivative is formed and on brief heating (65°) with the more basic sodium carbonate or methanolic sodium hydroxide (25°, 3 hr) complete methoxylation (320) occurs. Ethanolic ethoxide (25°, 1 hr) or sodium carbonate (35°) is sufficient to give complete ethoxy-dechlorination. The corresponding phenoxy derivatives are obtained on treatment with one (0°), two (15°, 1 hr), or three equivalents (25-70°, 3 hr) of various sodium phenoxides in aqueous acetone. The stepwise reaction with phenols, alcohols, or thiols proceeds in better yield in organic solvents (acetone or chloroform) with collidine or 2,6-lutidine as acid acceptors than in aqueous sodium bicarbonate. ... 

Diethyl succinate, reaction with sodium ethoxide, 46, 25... 

Sodium azide, reaction with l butyl chloroacetate, 46, 47 reaction with diazomum salt from o amino-f> -ni trobiphcny L, 46, 86 Sodium chlorodifluoroacetate, 47, SO reaction with tnphenylphosphme and benzaldehyde, 47, SO Sodium ethoxide, 46, 2S reaction with diethyl succinate, 46,2S Sodium formate as reducing agent in preparation of palladium catalyst, 46, 90... 

Sodium 2 methoxy ethoxide, reaction with vinylidene chloride to yield ketcne di(2 methoxyetbyl) acetal, 47, 78... 

Sodium ethoxide in deuterated ethanol was used in a study of the rate of deuteration of anisolechromium tricarbonyl at 100 °C, the first-order coefficient (2.65 x 10 5) being reported as only 3 times greater than that for benzene, cf anisole in the reaction with potassamide in liquid ammonia (Table 177)591a. 

Ethyl o-nitrophenylpyruvate and o-nitrophenylpyruvic acid 14-21 have been prepared by condensation of o-nitrotoluene with diethyl oxalate in the presence of potassium ethoxide,4 14 sodium ethoxide,16-20 or sodium methoxide.21 Sodium ethoxide is less reactive, however, and cannot be substituted successfully for potassium ethoxide in the present procedure, as it gives a very poor yield and poor quality of precipitated sodium salt. With sodium ethoxide the reaction does not appear to go to completion even under the conditions of refluxing ethanol usually employed,16-21 which are considerably more severe than the room temperature conditions employed with potassium ethoxide in the present procedure. o-Nitrophenylpyruvic add has also been prepared by hydrochloric acid hydrolysis of o-nitro-a-acetamino-dnnamic azlactone.4... 

Hydroxyimino-2-phenylacetonitrile has been prepared from benzyl cyanide by reaction with nitrous acid, with isoamyl nitrite and sodium ethoxide, and with butyl nitrite and hydrogen chloride." ... 

Olefination Reactions Involving Phosphonate Anions. An important complement to the Wittig reaction involves the reaction of phosphonate carbanions with carbonyl compounds 253 The alkylphosphonic acid esters are made by the reaction of an alkyl halide, preferably primary, with a phosphite ester. Phosphonate carbanions are generated by treating alkylphosphonate esters with a base such as sodium hydride, n-butyllithium, or sodium ethoxide. Alumina coated with KF or KOH has also found use as the base.254... 

Imidazolides of aromatic sulfonic acids react much more slowly in alcoholysis reactions than the carboxylic acid imidazolides. Although the reaction with phenols is quantitative when a melt is heated to 100 °C for several hours, with alcohols under these conditions only very slight alcoholysis is observed. In the presence of 0.05 equivalents (catalytic amount) of sodium ethoxide, imidazole sodium, of NaNH2, however, imidazolides of sulfonic acids react with alcohols almost quantitatively and exothermically at room temperature in a very short time to form sulfonic acid esters (sulfonates). (If the ratio of sulfonic acid imidazolide to alcoholate is 1 2, ethers are formed see Chapter 17). The mechanism of catalysis by base corresponds to that operative in the synthesis of carboxylic esters by the imidazolide method. Because of the more pronounced nucleophilic character of alkoxide ions, sulfonates can also be prepared in good yield by alcoholysis of their imidazolides in the presence of hydroxide ions i.e., with alcoholic sodium hydroxide. 45 Examples of syntheses of sulfonates are presented below. 

Reaction of compound 37 with bromine in chloroform results in mono-bromination a to the sulfur. Treatment of this brominated derivative with NaBH3CN in AcOH gives a mixture of products resulting from reduction of the C=N double bond and of elimination of HBr. Reaction of 44 with sodium ethoxide results in the ethoxy-substituted derivative 45, whereas reaction with pyridine gives the dehydrobrominated derivative 46. Reaction of either 44 or 46 with sodium cyanide in dimethyl sulfoxide (DMSO) gives the cyano-derivative 47 <1983HCA971> (Scheme 13). 

The enamine 141 can be cyclized to the [l,2,4]triazolopyridopyrimidine 142 upon treatment with sodium ethoxide (Scheme 40) <2002M1297>. This fused tricyclic system may also be obtained, like the pteridine analogue (cf. Scheme 38), from the reaction of hydrazonoyl halides and pyridopyrimidines such as 143, and also by treatment of the triazolopyrimidine 144 with dimethylformamide dimethylacetal (DMF-DMA) dimethylacetal and subsequent ring closure <2003MOL333, 2003HAC491> (Scheme 41). Another series of triazolopyridopyrimidines, for example, 146, can be prepared from a hydrazine-substituted pyridopyrimidine 145, in two ways either directly by reaction with an acid chloride, or via a derived hydrazone (Scheme 42) <1996MI585>. 

Sodium ethoxide, 46, 2S reaction with diethyl succinate, 46,25... 

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