Substituent effects of 2-aryl-trans-decahydroquinolin-4- ones in CTADC oxidation: Spectrophotometric approach

A kinetic study was carried out using spectrophotometric approach on the oxidation of nine differently substituted 2-aryl-trans-decahydroquinolin-4-ones by Cetyltrimethylammonium dichromate (CTADC) as oxidant at 30°C and in aqueous acetic acid (50%) containing catalytic amount of sulphuric acid (6N). The reactions were studied at 350 nm. The reaction was found to follow second order kinetics. The substitution of methyl group at position three of the decahydroquinoline ring and the presence of electron releasing groups in the aryl group increased the rate of oxidation of the substrates. The change in the rate of oxidation with temperature and solvent composition was also studied. The products formed during the oxidation were also confirmed by using high-performance liquid chromatography (HPLC) and spectral analysis.   Key words: 2-aryl-trans-decahydroquinolin-4-ones, kinetics, oxidation, Cetyltrimethylammonium dichromate (CTADC).