PART I. AN INVESTIGATION OF THE HYDROLYSES OF 1-CARBON-14-ALLYL CHLORIDE AND 1-CARBON-14-ALLYL MESYLATE. PART II. THE REACTION OF ALPHA- HALOISOBUTYROPHENONES WITH SODIUM NITRITE IN DIMETHYLSULFOXIDE

ALLAN EARNEST NADER, Purdue University

Abstract

Part I. The hydrolyses of 1-C('14)-allyl chloride and 1-C('14)-allyl mesylate were examined with particular reference to the possibility of rearrangement. The reaction of 1-C('14)-allyl chloride with aqueous sodium hydroxide solution, either as a homogeneous or heterogeneous process, occurs with complete lack of rearrangement. The allyl alcohol produced by the hydrolysis of 1-C('14)-allyl chloride in initially neutral water, under homogeneous conditions, is completely unrearranged. Homogeneous hydrolysis of 1-C('14)-allyl mesylate also gives unrearranged allyl alcohol. The fact that the aqueous alkaline hydrolyses of allyl chloride and allyl mesylate are second order processes and the absence of a salt effect when these compounds are solvolyzed in initially neutral water('1) agree with the isotopic results, and lead to the conclusion that these hydrolyses proceed as SN2 displacements. In addition, the stability of 1-C('14)-allyl alcohol to rearrangement, under the acidic conditions studied, is of interest. Part II. The recent proposal of a radical-anion mechanism for the carbon alkylation of a nitroparaffin salt with o- and p- nitrobenzyl halides('2) suggests the possibility of radical-anion processes in other substitution reactions. The (alpha)-haloisobutyrophenone system, C(,6)H(,5)COCX(CH(,3))(,2), also appears capable, in principle, of undergoing an electron transfer process upon treatment with a suitable anion. When (alpha)-chloroisobutyrophenone and (alpha)-bromoisobutyrophenone are treated with sodium nitrite in dimethylsulfoxide at 25(DEGREES), 95-98% yields of (alpha)-nitroisobutyrophenone aong with 2-5% of (alpha)-hydroxyisobutyrophenone are obtained. Kinetic studies show that the reactions are second order, the rate depending on the concentrations of salt and haloketone. The addition of methanol and acetylacetone, as proton sources, to the reaction mixture fails to alter the reaction course; no isobutyrophenone is detected. When the reaction is carried out in the presence of strong electron acceptors, such as p-dinitrobenzene, no change in products, or reaction rate is observed. In view of this facile reaction at a tertiary center to give almost exclusively the nitroketone, the more hindered of the two possible products, the operation of an electron transfer mechanism productive of radical-anion intermediates seems reasonable. But, the failure of p-dinitrobenzene to affect the reaction is at odds with this conclusion. The problem, then, remains unresolved for the present.

Degree

Ph.D.

Subject Area

Organic chemistry

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