The kinetics of oxidation of styrene and substituted styrenes by quinolinium dichromate (QDC) in dimethyl formamide, in the presence of acid, has been investigated. The rate of the reaction is dependent on the first powers of the concentrations of substrate, oxidant, and acid. A small inverse kinetic isotope effect has been observed (k d k D = 0.80). Correlation with cr yielded a p value of-4.0, suggesting the formation of a cationic intermediate in the rate-determining step of the reaction. Subsequent cleavage of the carbon-carbon bond yielded benzaldehyde and formaldehyde.

When treated with quinolinium dichromate (QDC) in acid medium using dimethylformamide as the solvent, cyclic alcohols were converted to the corresponding cyclic ketones. Kinetic data have been presented. The order of reactivity was 8 > 7 > 5 > 6. The reaction proceeds via a cyclic transition state, with the subsequent cleavage of the carbon–hydrogen bond (kH/kD = 5.8) in the rate determining step. The electrocyclic mechanism involved six electrons, and being a Hückel-type system (4n + 2), this was an allowed process.

Kinetic data on the rates of quinolinium dichromate oxidation of some bicyclic alcohols are reported and discussed with reference to the factors that influence the nature of the transition state. The mechanistic pathway has been visualized via the formation of the intermediate chromic ester which undergoes decomposition to give the product. A cyclic transition state is suggested; being a Hückel-type system (4n + 2), this would be an allowed process.

Cyclopropane derivatives Q 0021Novel Synthesis of Substituted Cyclopropane Acetic Acid Ethyl Esters from Cyclopropyl Alkyl Ketones. -The reaction proceeds via a lead tetraacetate/perchloric acid assisted 1,2-carbonyl transposition. A probable mechanism is discussed. -(NONGKHLAW, R. L.; NONGRUM, R.; NONGKYNRIH, I.; VATTAKUNNEL, F. M.; MYRBOH*, B.; Indian J.

No abstract