Title

Interaction of sulfur-dioxide with 1-benzyl-1,4-dihydronicotinamide and reactions of Rongalite with organic halides

Date of Award

1988

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Advisor(s)

Donald C. Dittmer

Keywords

Sulfer dioxide, Sodium hydroxymethanesulfinate dihydrate

Subject Categories

Organic Chemistry

Abstract

During a study of intramolecular NADH coenzyme-substrate model systems, oxidation of 1,4-dihydronicotinamides to the corresponding pyridinium ions by sulfur dioxide was observed. Qualitative analyses performed on the product mixture from the reaction of sulfur dioxide with 1-benzyl-1,4-dihydronicotinamide (BNAH) suggested the presence of thiosulfate, sulfite, bisulfite, and/or adsorbed sulfur dioxide. The initially formed reduced species of sulfur dioxide may have been HSO$\sb2\sp-$, the product of direct hydride transfer, since in the presence of Michael acceptors sulfones are formed. ESR experiments suggested the presence the known species SO$\sb2\sp{-\bullet}$ or (SO$\sb2\sp{-\bullet}$)(SO$\sb2$) when the reaction of BNAH with sulfur dioxide was run in methanol or DMF, respectively. The presence of these radicals suggests that initial single-electron transfer may occur with subsequent transfer of a hydrogen atom to give HSO$\sb2\sp-$, although the radicals might have been formed by subsequent reactions of initially formed HSO$\sb2\sp-$.

The second part of this study involved a survey of the reactions of sodium hydroxymethanesulfinate dihydrate (Rongalite), a convenient source of reduced species of sulfur dioxide presumably similar to those obtained from BNAH-sulfur dioxide, with organic halides. Reactions of mixtures of Rongalite, potassium bicarbonate, and benzyl or alkyl bromides in DMF-water mixtures offer a convenient method for the preparation of symmetrical sulfones. Bis(4-nitrobenzyl) sulfone was the product of the reaction between 4-nitrobenzyl bromide and Rongalite in the absence of bicarbonate whereas in the presence of bicarbonate the only product isolated was 4,4$\sp\prime$-dinitrobibenzyl. Three previously unknown sulfones were synthesized from the corresponding benzyl bromides: bis(4-fluorobenzyl), bis(2-methylbenzyl), and bis(3-nitrobenzyl) sulfones. Reaction of Rongalite with $\alpha$,$\alpha\sp\prime$-dibromo-o-xylene at 80$\sp\circ$C yielded a polymeric product mixture which appeared to be mainly poly(o-xylylene) whereas at 40$\sp\circ$C this reaction yielded 2,3-benzoxathiin-3-oxide. The formation of o-xylylene in these reactions was confirmed by trapping it with norbornene. Reaction of Rongalite with phenacyl chloride gave acetophenone, while the corresponding reaction with phenacyl bromide gave not only the product of reduction, acetophenone, but also the product of reductive coupling, 1,4-diphenyl-1,4-butanedione.

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