2- ethoxide

Prepared by healing benzaldehyde with sodium ethanoate and ethanoic anhydride (Perkin reaction) or with ethyl ethanoate and sodium ethoxide. Occurs in storax, or liquid... 

Claisen condensation Condensation of an ester with another ester, a ketone or a nitrile in the presence of sodium ethoxide, sodium or sodamidc, with the elimination of an alcohol. The result is the formation of a / -ketonic ester, ketone, or nitrile respectively, e.g. 

CqHaOj. Colourless crystals m.p. lOS C. Obtained by boiling coumarin with sodium ethoxide. Irradiation of o-coumaric acid produces coumarinic acid. The stable form of the acid is the trans form. 

Figure Bl.25.9(a) shows the positive SIMS spectrum of a silica-supported zirconium oxide catalyst precursor, freshly prepared by a condensation reaction between zirconium ethoxide and the hydroxyl groups of the support [17]. Note the simultaneous occurrence of single ions (Ff, Si, Zr and molecular ions (SiO, SiOFf, ZrO, ZrOFf, ZrtK. Also, the isotope pattern of zirconium is clearly visible. Isotopes are important in the identification of peaks, because all peak intensity ratios must agree with the natural abundance. In addition to the peaks expected from zirconia on silica mounted on an indium foil, the spectrum in figure Bl. 25.9(a)...

Sodium ethoxide gives an ether (Williamson s reaction). 

This Reaction should be carefully distinguished from the Claisen Conden-tation, which is the condensation of an ester, under the influence of sodium ethoxide, with (i) another ester, (ii) a ketone, or (iii) a nitrile, with the elimination of alcohol. For details of this condensation, see Ethyl Acetoacetate, p. 264. 

It is readily prepared by the action of metallic sodium on dry ethyl acetate. The reaction, which occurs only in the presence of a trace of ethanol, is complex, but may be considered (in effect) as a condensation of two molecules of ethyl acetate under the influence of sodium ethoxide, the sodium derivative of the enol form being thus obtained. Clearly, only a trace of ethanol is thus initially... 

Mono and Di-iubstitution Derivatives. The enolic sodium derivative of ethyl acetoacetate (E) is prepared by mixing ethanolic solutions of the ester and of sodium ethoxide. It should not be prepared by the direct action of metallic sodium on the ester, as the reaction is slow and the nascent hydrogen evolved reduces some of the ester to ethyl p4iydroxy- butyrate, CH3CH(OH)CHjCOOEt. 

Substitution Derivatives of Ethyl Malonate, Ethyl malonate resembles ethyl acetoacetate in that it gives rise to mono- and di-substituted derivatives in precisely similar circumstances. Thus when ethanolic solutions of ethyl malonate and of sodium ethoxide are mixed, the sodium derivative (A) of the enol form is produced in solution. On boiling this solution with an alkyl halide, e.g, methyl iodide, the methyl derivative (B) of the keto form is obtained. When this is treated again in ethanolic solution with sodium ethoxide, the... 

Place 30 ml. of ethanol in a 200 ml. conical flask fitted to a reflux water-condenser, and then add 1-4 g. of sodium cut into small pieces. The sodium rapidly dissolves to give a solution of sodium ethoxide, the ethanol boiling under the heat of the reaction. When the sodium has completely dissolved, detach the flask and cool it in ice-water. 

While the sodium ethoxide solution is cooling, prepare a solution of 7 7 g. of finely powdered iodine in 60 ml. of ether. When this solution is ready, add 9 ml. (9 6 g.) of ethyl malonate to the ethanolic sodium ethoxide solution, mix w ell and then allow to stand for 30-60 seconds not longer) then cautiously add the ethereal solution of the iodine, mixing thoroughly during the addition in order to avoid local overheating by the heat of the reaction. (If, after the ethyl malonate has been added to the sodium ethoxide, a considerable delay occurs before the iodine is added, the yield of the final product is markedly decreased.)... 

Ethane tetracarboxylic ethyl ester can be regarded as composed of two malonic ester residues, each acting as a mono-alkyl substituent to the other. The two remaining hydrogen atoms therefore still retain acidic properties, and consequently the ester gives with sodium ethoxide a di-sodium derivative. 

Barbituric acid and 2-thiobarbituric acid are readily prepared by the condensation of diethylmalonate with urea and thiourea respectively, in the presence of sodium ethoxide. The use of substituted derivatives of urea and thiourea and of diethyl malonate will clearly lead to a wide range of barbituric and thiobarbituric acids having substituents in the i, 3, or 5 positions. 

Reaction (1) usually proceeds readily provided the magnesium is activated with iodine and the water content does not exceed one per cent. Subsequent interaction between the magnesium ethoxide and water gives the highly insoluble magnesium hydroxide only a slight excess of magnesium is therefore necessary. 

The sodium formate is sparingly soluble in ethyl alcohol and therefore separates out. The residual ethyl formate is catalytically decomposed in the presence of sodium ethoxide at the boUing point of the ethyl alcohol, t.e., by refluxing the mixture ... 

There are no liquid alkynes whieh can be conveniently prepared by the elementary student. Some of the properties of aeetylenie hydrocarbons may be studied with the gas, aeetylene. Although the latter may be prepared in moderate 3deld by the addition of ethylene dibromide to a boiling aleoholic solution of potassium hydroxide or of sodium ethoxide,... 

P Keto esters (t.g., ethyl ocetoacetate) are soluble in solutions of caustic alkalis but not in sodium carbonate solution. They give colours with freshly prepared ferric chloride solution a little alcohol should be added to bring the ester into solution. Sodium ethoxide solution reacts to yield sodio compounds, which usually crystallise out in the cold. Phenylhydrazine yields pyrazolones. They are hydrolysed by boiling sulphuric acid to the Corresponding ketones, which can be identified as usual (Section 111,74). 

The sodio derivative, which is prepared by mixing alcoholic solutions of the ester and of sodium ethoxide, condenses with alkyl halides to yield mono-alkyl C-substituted products, for example ... 

The mono-alkyl C-substituted derivatives of ethyl acetoacetate upon treatment with sodium ethoxide and another molecule of alkyl halide afford the di-alkyl C-substituted products... 

The formation of ethyl acetoacetate is an example of a general reaction knowu as the acetoacetlc ester condensation in which an ester having hydrogen on the a-carbon atom condenses with a second molecule of the same ester or with another ester (which may or may not have hydrogen on the a-carbon atom) in the presence of a basic catalyst (sodium, sodium ethoxide, sodamide, sodium triphenylmethide) to form a p-keto-ester. The mechanism of the reaction may be illustrated by the condensation of ethyl acetate with another molecule of ethyl acetate by means of sodium ethoxide. ... 

The first step is the interaction of the basic catalyst with the ester to produce the carbanion (I) the carbanion so formed then attacks the carbonyl carbon of a second molecule of ester to produce the anion (II), which is converted to ethyl acetoacetate (II) by the ejection of an ethoxide ion. Finally (III) reacts with ethoxide ion to produce acetoacetic ester anion (IV). This and other anions are mesomeric thus (IV) may be written ... 

The equilibrium of the last step (3), which is not actually part of the condensation mechanism, is far to the right because of the greater basic strength of the ethoxide ion as compared to (IV), and this largely assists the forward reactions in (1) and (2). The reaction mixture contains the sodium derivative of the keto-ester, and the free ester is obtained upon acidification. 

Alternatively, it may bo assumed that the basic ethoxide ion attacks a hydrogen atom of the activated CH, group to yield the carbanion directly ... 

Malonic ester, like acetoacetic ester (Section 111,151), when treated with an equivalent of sodium ethoxide, forms a mono-sodium derivative, which is of great value in synthetical work. The simplest formulation of the reaction is to r rd it as an attack of the basic ethoxide ion on a hydrogen atom in the CH, group the hydrogen atoms in the CHj group are activated by the presence of the two adjacent carbethoxyl groups ... 

Where R and R are identical, the dialkylmalonic ester may be prepared in one operation by treating 1 mol of ethyl malonate with 2 mots each of sodium ethoxide and the alkyl halide (usually bromide or iodide). 

Ethyl cyanoacetate (Section 111,131) is sometimes preferable to diethyl malonate for the synthesis of acids. It forms a sodio derivative with sodium ethoxide ... 

Pelargonic acid (n-Nonoic acid), CH3(CH2),COOH. Equip a 1-litre, three-necked flask with a reflux condenser, a mercury-sealed stirrer, a dropping funnel and a thermometer. Place 23 g. of sodium, cut in small pieces, in the flask, and add 500 ml. of anhydrous n-butyl alcohol (1) in two or three portions follow the experimental details given in Section 111,152 for the preparation of a solution of sodium ethoxide. When the sodium has reacted completely, allow the solution to cool to 70-80° and add 160 g. (152 ml.) of redistilled ethyl malonate rapidly and with stirring. Heat the solution to 80-90°, and place 182 5 g. (160 ml.) of n-heptyl bromide (compare experimental details in Section 111,37) in the dropping funnel. Add the bromide slowly at first until precipitation of sodium bromide commences, and subsequently at such a rate that the n-butyl alcohol refluxes gently. Reflux the mixture until it is neutral to moist litmus (about 1 hour). 

Wolff - Kishner reduction of aldehydes and ketones. Upon heating the hydrazoiie or semicarbazone of an aldehyde or ketone with potassium hydroxide or with sodium ethoxide solution (sealed tube), the corresponding hydrocarbon is obtained ... 

These may be hydrolysed to the monosulphonyl derivatives by boiling for 30 minutes with a 5 per cent, solution of sodium ethoxide in ethyl alcohol ... 

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