| Competitive thermal fragmentation of 2-(hydroxymethyl)-3,3-diphenyl-1-(2,4,6-trimethylphenyl)propan-1-one (2) leading to the formation of a mixture of 3,3-diphenyl-1-(2,4,6-trimethyl)propan-1-one (Kohler's ketone (1)) and 2-(diphenylmethyl)-1-(2,4,6-trimethylphenyl)prop-2-en-1-one (3) was studied. The effect of Pyrex, Kimax, soft-glass and fused quartz, their surface areas and conditions are reported. The activation parameters for dehydration and formaldehyde elimination reactions of (2), in the presence of Pyrex glass were obtained by a kinetic study. The effect of soft glass was different compared to Pyrex, Kimax and fused quartz. Mechanisms are proposed to explain these observations.;Thermal fragmentation of (2) in solution indicated that the major portion of (2) underwent dehydration in bis(2-ethoxyethyl) ether solution compared to mesitylene and diphenyl ether solutions. Preliminary GC-MS studies on other ;The conjugate addition of phenylmagnesium bromide to benzalacetomesitylene which was one of the intermediate steps in the synthesis of ;The E enol was prepared by the enolization reaction of Kohler's ketone (1) with methylmagnesium iodide followed by hydrolysis. The E enol appeared at a retention time of 3.6 min compared with that of the Z enol at 4.1 min on the HPLC chromatograms. The relative rates of oxidation were approximately 7:1 for Z:E enols, respectively. An explanation is presented for the faster oxidation of the Z enol. |
