A-Hydroxysulfones

Sodium bisulfite adds to the carbonyl double bond to give a hydroxysulfonate (bisulfite addition compound). 

Fig. 2-29. Formation of a-hydroxysulfonic acids after addition of hydrogen sulfite ions to aldoses. R = the monosaccharide residue.

Fig. 7.7. Sulfonation of coniferaldehyde end groups and substituted structures containing a-carbonyl groups (see Gellerstedt, 1976). At lower temperatures aldehyde end groups can bind sulfur dioxide because of the formation of a-hydroxysulfonic acid.

In the course of the reactions described in section (I) the complex silver and bismuth ions are reduced to the metal by the -CHO group of the aldehyde. No reaction occurs if this group is not present (paraldehyde). In reaction (II) the SO3 group of the fuchsinesulfurous acid is split off and adds to the aldehyde to form an a-hydroxysulfonic acid. The color of the fuchsine itself is now visible. All the normal reactions of an aldehyde are observed if acetaldehyde is set free from its trimer paraldehyde. Sulfuric acid catalyses both the forward and back reactions in this equilibrium (eqn. 1) ... 

Incorporation of methanol at the rate of 2 kg/kg phosphorus pentoxide in the dried acidulate significantly improves the purity of the phosphoric acid product in a two-stage process. This modification is especially advantageous with a low-grade phosphate rock [42]. Acetone has also been found of value in an experimental variant which enables much less expensive sulfurous acid, rather than sulfuric acid, to be used as the acidulant [43]. In this case, the solvent forms an a-hydroxysulfonic acid with the sulfurous acid (Eq. 10.27) which is sufficiently strong to attack phosphate rock at a reasonable rate. 

In Mandai s approach [47], condensation of a suitable sulfone with the appropriate succinic amide-hemialdehyde affords a hydroxysulfone, whose acetate, on treatment with base, gives the corresponding dienoic amide. In this manner, sarmentine, 9(n=4), the Achillia amide 10(n=4), and piperine, 42 were synthesized (ca. 90% E,E ) in good overall yield (Scheme 8). 

The central depressant activity of 11 syndietic derivatives, differing from one another only by die nature of the chain linked to trimedioxy-3,4, 5-phenylsulfonyl was studied in mice. It was shown that die most active molecules are a hydroxysulfone with a primary alcohol grouping and a low partition coefficient in an octanol/water system and 3 aminosulfones widi a nitrogen atom, a part of a piperidine cycle or substituted by alkyls and widi log P close to 2 and pJC ranging from 7.1 to 7.6."... 

The a-hydroxysulfonates are not oxidized by iodine in neutral or acid solutions, but this does occur in alkaline solutions where it is preceded by dissociation into the free sulfite. They are also not readily oxidizable by oxygen. 

The formation of the a-hydroxysulfonic acids is influenced by concentration of the reactants (carbonyl compound and bisulfite), temperature, and pH. The rate of association as influenced by the relative concentration of bisulfite, aldehyde, and sugars was investigated early by Kerp (1904) and his collaborators and others, and more recently by Ingram and Vas (1950b) and by the Corn Products Refining Company. The effect of pH and temperature on dissociation of the sulfonic acids has been investigated also for some of the compounds (see the review by Suter,... 

A variation of the Wittig reaction was described [14, 15] in which a-hydroxysulfonates (13) were used, instead of aldehydes, to react with phosphonium salts. Polymers with only traru-vinylene units were formed (Scheme 5). 

For a considerable period following its discovery, sodium formaldebvde bisulfite was belie ed to possess the structure of a hydroxy sulfite ester, HOCHiOSOoNa. This formula was incorrect, and it has now been established that its stnictuie is that of a hydroxysulfonic acid, HOCHiSOsKa. This structure is based on the studies of Raschig and Prahl i> 2 in 1926-8 and Lauer and Langkammerer in 1935. 

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