Sodium benzylate

Salts composed of an anion, RO—, and a cation, usually a metal, can be named by citing first the cation and then the RO anion (with its ending changed to -yl oxide), e.g., sodium benzyl oxide for CgH5CH20Na. However, when the radical has an abbreviated name, such as methoxy, the ending -oxy is changed to -oxide. For example, CHjONa is named sodium methoxide (not sodium methylate). 

Ethyl Acetoacetate. -The e. planation of the manner in which this substance is produced has been given in the account of the preparation. The result was anived at, not by the iscila-tion of the intermediate compound formed by the union of ethyl acetate with sodium ethylate, but by analogy with the behaviour of benzoic methyl ester with sodium benzylate, which gave the same additive product as that obtained by combining benzoic benzyl ester with sodium methylate, showing that such combinations could occur,... 

In the presence of sodium benzylate two molecules of benzal-dehyde react with the alcoholate to form an addition product. When the reaction mixture is overheated an important side... 

The causes of variations in yield by the use of the okler methods can now be explained. When benzaldehyde is added to the alcoholate, and especially when the latter is still warm, local overheating results in fact, the temperature may rise far above xoo° with the result that benzyl ether is formed. Simultaneously, the sodium benzylate is converted into sodium benzoate, which is of no value for inducing the desired reaction, and consequently very little benzyl benzoate is obtained. The same side reactions explain the failure of this experiment when the benzyl alcohol used in preparing the catalyst (sodium benzylate) is contaminated with benzaldehyde. 

Pines and Kolobielski (18) have shown that phenylcyclohexene, although it is not a cyclic diolefin, will also undergo reactions similar to those that cyclic diolefins undergo when treated with base catalysts. When heated to 200-220 with a sodium-benzyl-sodium catalyst, it underwent a hydrogen transfer reaction resulting in the formation of biphenyl and of phenyl-cyclohexane molecular hydrogen was not produced. The mechanism of this reaction may be pictured as an elimination of sodium hydride from one molecule with the hydride ion being accepted by another molecule (A"-E"). 

Arylalkenes can undergo various reactions when treated with sodium, since compounds such as a-methylstyrene are both olefins with allylic hydrogens and styrenes, both of which are reactive. The reaction of a-methylstyrene with sodium has been reported by Bergmann et al. (6i) to yield tetramers. More recent work by Kolobielski and Pines (56) has shown that dimers and products derived from dimers are formed when this compound is heated with a sodium-benzyl-sodium catalyst. Some of the major products were cumene (VII), p-terphenyl (VIII), and 1-methyl-1,3-diphenyl-cyclopentane (IX). 

When sodium methylate or ethylate was prepared by direct reaction of sodium with an excess of alcohols and the resulting mixture was used as a dispersion in benzene to reduce aromatic nitro compounds, yields of azoxy compounds were quite low. With the higher alcohols, substantial production of azoxy compounds was observed. However, the reduction product mixture usually contained a 40 % yield of amino compounds. In a few examples, where benzyl alcohol was used to prepare sodium benzylate, only azoxy products and no amino by-products were formed. The scope of this preparation requires further study. 

A polymerization unit containing separate glass ampoules of purified w-hexylisocya-nate, the initiator, and a reaction terminator, was connected to a vacuum and then sealed. The reaction conditions were — 98°C and 1 x 10-6 torr with a reaction time between 5 and 15 minutes. To set the reaction temperature, liquid nitrogen was added to methanol contained in a constant temperature bath to freeze the methanol and the temperature measured using a low-temperature thermometer. The initiator, sodium-benzyl phenyl ketone, was obtained by reacting sodium metal with an equivalent amount of benzyl phenyl ketone in THF and used immediately. The terminator consisted of hydrochloric acid-methanol mixture solution. Reaction scoping results are provided in Table 1. 

TABLE 1. Reaction Scoping for Anionic Polymerization of n-Hexylisocyanate Using Sodium-Benzyl Phenyl Ketone as Initiator... 

Fig. 214. Sodium benzyl penicillin, (a) Approximate electron density map, b projection, with atomic coordinates appropriate to extended molecular configuration. (6) Error synthesis map. (c) The same electron density map as (a), with atomic coordinates appropriate to a curled configuration of the same molecule.

In the presence of sodium benzylate 2 mols. of benzaldehyde polymerise to yield benzyl benzoate. The reaction is peculiar to aromatic aldehydes. 

Metal alkoxides, such as sodium benzylate, in catalytic amounts promote the [2,3]-Wittig rearrangement of silyl enolates (34), to afford the corresponding rearrangement product (35) in good yields at room temperature (Scheme 8).23... 

A related radical transformation can be used to prepare 2,2-disubstituted selenanes. Treatment of the alcohol 124 with oxalyl chloride followed by addition of 2-mercaptopyridine iV-oxide and heating afforded the selenane 125 in moderate yield (Scheme 11) <2001JOC6286>. The required alcohol precursor for this reaction can be readily prepared from the bromo ester and in ////-generated sodium benzyl selenide, followed by Grignard addition. 

Alcoholic potassium hydroxide and sodium alcoholates have also been used as reducing agents for aromatic nitro compounds the free alcohol or the alcoholate ion presumably acts as the reducing agent in these cases as illustrated for w,m -diiodoazoxybenzene (8 equation 6). In a few instances, where benzyl alcohol was used to prepare sodium benzylate, pure azoxy products were obtained without the formation of amino by-products. 

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