Aldehydes bisulfite addition

An elegant method for the gentle and selective oxidation of aldehydes to carboxylic acids is the oxidation of the aldehyde-bisulfite addition compound by dimethyl sulfoxide. Depending on the workup of the reaction mixture, the acid, its ester, or its amide can be prepared at room temperature (equation 353) [773]. 

Not-Strike may have seen. But what Dr. Quack did that SWINS did not was use the bisulfite test with positive results. What does that mean It means that some doublebonded oxygen was formed, unless Dr. Quack was fibbing to us, It cannot have been a propiophenone (don t ask) because propiophenones cannot form the bisulfite addition product. Could an aldehyde have formed (don t ask) Maybe. But highly unlikely considering the mechanism of the reaction. 

Ketones are more stable to oxidation than aldehydes and can be purified from oxidisable impurities by refluxing with potassium permanganate until the colour persists, followed by shaking with sodium carbonate (to remove acidic impurities) and distilling. Traces of water can be removed with type 4A Linde molecular sieves. Ketones which are solids can be purified by crystallisation from alcohol, toluene, or petroleum ether, and are usually sufficiently volatile for sublimation in vacuum. Ketones can be further purified via their bisulfite, semicarbazone or oxime derivatives (vide supra). The bisulfite addition compounds are formed only by aldehydes and methyl ketones but they are readily hydrolysed in dilute acid or alkali. 

Impurities resulting from storage can be removed by passage through chromatographic grade alumina. Furfural can be separated from impurities other than carbonyl compounds by the bisulfite addition compound. The aldehyde is steam volatile. 

An alternate method of producing the 21-hydroxy-20-ketone consists in lithium aluminum hydride reduction of the dimethyl acetal, hydrolysis to the 20-hydroxy-21-aldehyde and rearrangement, preferably via the bisulfite addition product... 

Bisulfite addition products are formed from aldehydes, methyl ketones, cyclic ketones (generally seven-membered and smaller rings), a-keto esters, and isocyanates, upon treatment with sodium bisulfite. Most other ketones do not undergo the reaction, probably for steric reasons. The reaction is reversible (by treatment of the addition product with either acid or base ) and is useful for the purification of the starting compounds, since the addition products are soluble in water and many of the impurities are not. ... 

Frequently, it is the bisulfite addition product that is treated with CN. This method is especially useful for aromatic aldehydes, since it avoids competition from the benzoin condensation. If desired, it is possible to hydrolyze the cyanohydrin in situ to the corresponding a-hydroxy acid. This reaction is important in the Kiliani-Fischer method of extending the carbon chain of a sugar. 

Bisulfite Adduct. A bisulfite addition complex of an aldehyde or dialdehyde has been proposed for use as an antimicrobial agent [1858,1859]. The complex is less toxic than free glutaraldehyde. In oil wells, its digestion by the sulfate-reducing bacteria releases the free dialdehyde that controls the bacteria. In these ways, a more economic and environmentally safer use of antimicrobial additives is likely. 

A solution of 10 g (0.06 mol) of ethyl thiolbenzoate in 200 ml of 70% ethanol is refluxed for 6 hours with 50 g of Raney nickel. After the removal of the catalyst the filtrate is distilled and the aldehyde is isolated from the distillate by treatment with a saturated (40%) solution of sodium bisulfite. The yield of benzaldehyde-sodium bisulfite addition complex is 8.0 g (62%). 

The crude aldehyde (prior to distillation) is sufficiently pure for most purposes. Isolation of the aldehyde may also be achieved by means of the bisulfite-addition compound.2... 

This can be remedied by using commercially available one-component reagents that contain 2-methoxyethanol and 2-chloroethanol rather than methanol. In the presence of S02 and base, aldehydes, undergo what is called the bisulfite addition. 

The postulated 1-aminoalkylarsonic acids have something in common with 1-hydroxyalkanesulfonic acids, R—CHOH—S03-. These are not usually known as such, but as bisulfite addition compounds of aldehydes. They are not usually isolable, because of the ease of the reaction shown in Fig. 14. In just the same way we might expect R— CH(—NH3+)—As03H to lose arsenite as H2As03" and H+, i.e., H2As03" overall, leaving the imine R—CH=NH2+, which would equilibrate with R—CH=0 and NH4+. So this would explain why 1-amino-alkylarsonic acids may not exist as stable compounds. 

Seventeen grams of acetaldehyde are dissolved in 20ml of water and added dropwise to a suspension of 40g of sodium bisulfite in 30ml of water. The reaction mixture is kept cold in an ice bath to prevent loss of the aldehyde by volatilization much heat Is liberated by the formation of the bisulfite addition compound. The temperature of the solution is adjusted to 50°C and 17ml of 20% aqueous ammonia are added. The latter is prepared from 13ml of the... 

Cyanohydrins can be formed by the acid- or base-catalyzed reaction of hydrogen cyanide with an aldehyde or ketone, the displacement of bisulfite ion by cyanide ion on the bisulfite addition compounds of aldehydes and... 

This is probably the single most important material used by the fragrance industry. Several million pounds are used annually, mainly in soaps and detergents. The principal method of manufacture shown in Figure 10 is by hydration of citronellal via the bisulfite addition product (2). The aldehyde moiety must be protected before hydration. A second manufacturing process starts with citronellol which is hydrated under acid conditions. The primary alcohol end of the molecule is then dehydrogenated catalytically or by oxidation to the aldehyde. 

Aldoses behave like aldehydes, but react much more slowly. The bisulfite addition compound is much more unstable. When, say, acetaldehyde is added to a glucose-bisulfite solution, the bisulfite will be transferred to it. 

Possible toxic reactions of sulfur dioxide are also indicated in Table I. The reaction of bisulfite with aldehydes has a classic position in biochemistry since Neuberg demonstrated in 1918 that the products of fermentation by yeast were altered by the addition of sodium sulfite, which caused the production of equal amounts of the bisulfite addition compound of acetaldehyde and of glycerol. This was concomitant with the blockage of conversion of acetaldehyde to ethanol. Addition compounds can also be formed with quinones and with ,/ -unsaturated compounds. None of these reactions has been adequately assessed as a possible contributor to toxicity. 

The last nucleophile of this chapter, sodium bisulfite, NaHSC, adds to aldehydes and some ketones to give what is usually known as a bisulfite addition compound. The reaction occurs by nucleophilic attack of a lone pair on the carbonyl group, just like the attack of cyanide. This leaves a positively charged sulfur atom but a simple proton transfer leads to the product. 

The products are useful for two reasons. They are usually crystalline and so can be used to purify liquid aldehydes by recrystallization. This is of value only because this reaction, like several you have met in this chapter, is reversible. The bisulfite compounds are made by mixing the aldehyde or ketone with saturated aqueous sodium bisulfite in an ice bath, shaking, and crystallizing. After purification the bisulfite addition compound can be hydrolysed back to the aldehyde in dilute aqueous acid or base. 

Condensation of sodium salts of acinitroalkanes with the sodium bisulfite addition products of aldehydes in the presence of trace of alkali or weak acid also gives nitro alcohols as reported byKamlet o. 

Benzal chlorides. Benzaldehyde or the bisulfite addition product reacts with thionyl chloride and DMF at -10 20° to form benzal chloride, QHsCHCU, in 88% yield. Newman favors structure 1 for the Vilsmeier complex involved in this reaction. This reaction is general for aromatic aldehydes and a, -unsaturated aldehydes. The reaction is not observed with diaryl ketones. 

Bisulfite addition products are readily formed at wine pHs (1, 23, 24). The bisulfite addition product is thought to be a more sensory-neutral compound and may be exploited by winemakers as a means of decreasing the aldehydic character of wines (1). Bisulfite addition has also been used to mask the stale flavor of beer which is thought to be largely due to the formation of trans-l-noneml (25). Kaneda et al. (25) used HPLC with fluorescent detection of an o-phthalaldehyde derivative to quantitate and identify individual aldehyde-bisulfite products, however, only acetaldehyde-bisulfite adducts were observed in commercial beers with this method. Hydrolysis of the adducts occurs at pHs greater than 8, therefore by adjusting the pH prior to analysis, total aldehydes (free plus bisulfite bound) can be estimated. At low pHs accurate estimation of free aldehydes is complicated however, by analysis conditions which alter the equilibrium between bound and free forms (temperature, dilution, solvent extraction, analysis time, etc.). 

The yields of nitro alcohols from simple nitroparaffins and aliphatic aldehydes or benzaldehyde are usually above 60%. The condensations are generally carried out with aqueous ethanolic sodium hydroxide, although weaker bases are sometimes desirable to prevent polymerization of the aldehyde. Sodium bisulfite addition compounds of the aldehydes are sometimes used. Better results are obtained with sodium methoxide than with alkali hydroxides in the condensation of nitroethane with formaldehyde. Sodium alkoxides are also used to effect the condensation of nitroethane with acetone and cyclohexanone. Condensation proceeds to the nitroalkanediol stage in certain cases with both nitromethane and with formaldehyde. ... 

The sodium bisulfite addition products of aldehydes have been converted by the action of potassium cyanide and an amine to a-alkylamino cyanides. The procedure is best suited for obtaining amino nitriles derived from formaldehyde and simple amines and is illustrated in the preparation of diethylaminoacetonitrile (90%). ... 

Since these bisulfite addition compounds are ionic water-soluble compounds and can be formed in up to 90% yield, they serve as a useful means of separating aldehydes and methyl ketones from mixtures of organic compounds. At high sodium bisulfite concentrations these adducts crystallize and can be isolated by filtration. The aldehyde or ketone can be regenerated by adding either a strong acid or base ... 

Bisulfite Test. Follow the procedure on page 313, Chapter 30. Nearly all aldehydes and most methyl ketones form solid, water-soluble bisulfite addition products. 

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