Sodium bisulfite, reaction with carbonyl

Several representative compounds from which abnormal products had been previously isolated in ozonizations carried out by other investigators were selected to test the above theory. Ozonizations were carried out in pure methanolic solutions at about —20° C. and in each case the yield of peroxide, based on the ozone consumed, was determined quantitatively. Overozonization was avoided, inasmuch as excess ozone is known to cause side reactions or decomposition of the peroxides (5). The peroxides thus formed were reduced with aqueous sodium bisulfite and the carbonyl compounds isolated as their 2,4-dinitrophenylhydrazones, which were separated quantitatively by chromatography through a mixture (2 to 1) of silica gel and Celite. In no case were any of the abnormal products found. The results are summarized in Table I. 

Acetaldehyde can be isolated and identified by the characteristic melting points of the crystalline compounds formed with hydrazines, semicarbazides, etc these derivatives of aldehydes can be separated by paper and column chromatography (104,113). Acetaldehyde has been separated quantitatively from other carbonyl compounds on an ion-exchange resin in the bisulfite form the aldehyde is then eluted from the column with a solution of sodium chloride (114). In larger quantities, acetaldehyde may be isolated by passing the vapor into ether, then saturating with dry ammonia acetaldehyde—ammonia crystallizes from the solution. Reactions with bisulfite, hydrazines, oximes, semicarb azides, and 5,5-dimethyl-1,3-cyclohexanedione [126-81 -8] (dimedone) have also been used to isolate acetaldehyde from various solutions. 

The key butenolide needed by Buszek, for his synthesis of (—)-octalactin A, had already been prepared by Godefroi and Chittenden and coworkers some years earlier (Scheme 13.4).9 Their pathway to 10 provides it in excellent overall yield, in three straightforward steps from l-ascorbic acid. The first step entails stereospecific hydrogenation of the double bond to obtain L-gulono-1,4-lactone 13. Reduction occurs exclusively from the sterically less-encumbered ot face of the alkene in this reaction. Tetraol 13 was then converted to the 2,6-dibromide 14 with HBr and acetic anhydride in acetic acid. Selective dehalogenation of 14 with sodium bisulfite finally procured 10. It is likely that the electron-withdrawing effect of the carbonyl in 14 preferentially weakens the adjacent C—Br bond, making this halide more susceptible to reductive elimination under these reaction conditions. 

The reaction is reversible, but the state of equilibrium highly favors the desired products. Preparations of large quantities for synthetic work are illustrated for methyl ethyl ketoxime, cyclohexanone oxime, hept-aldoxime, and benzophenone oxime, the procedures varying somewhat with the nature of the carbonyl compound. In some instances, a readily available and cheap reagent like sodium hydroxylamine disulfonate, HON(SO,Na)j, is first prepared from sodium nitrite and sodium bisulfite and, without isolation, treated with the carbonyl compound, Hydioxylamine-O sulfonic add, Ii,NOSO,H, is still another reagent and, like sodium hydroxylamine disulfonate, is used in the absence of a base. The preparation of hydroxylamine hydrochloride is described. ... 

The acid-catalyzed Pictet-Spengler reaction between tryptamine derivatives and aldehydes is a well-established method for preparing tetrahydro-p-carboline (THpC) derivatives." Our first trials were aimed at using the bisnlfite adduct as the carbonyl sonrce in order to minimize the number of process steps. The reaction was performed by reacting the 5-methyltryptamine hydrochloride with an excess (1.3 eqniv) of the sodium bisulfite adduct in EtOH at reflnx, in the presence of one extra eqnivalent of HCl. The rac-THpC was simply isolated as a hydrochloride salt by filtration of the reaction mixture (Scheme 6.8). 

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