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R T WILLIAMS

Publications and source records attributed to R T WILLIAMS.

At least 19 recordsLinked to original sources
PubMed1965

STEREOCHEMICAL ASPECTS OF THE METABOLISM OF THE ISOMERIC METHYLCYCLOHEXANOLS AND METHYLCYCLOHEXANONES.

1. The seven isomeric optically inactive forms of methylcyclohexanol (i.e. 1-, and cis- and trans-2-, -3- and -4-) are excreted by rabbits mainly as glucuronides of the thermodynamically more stable forms of the alcohols. The eighth isomer, cyclohexylmethanol, however, undergoes aromatization in vivo, giving rise to benzoic acid and hippuric acid. The (+/-)-2-, (+/--3- and 4-methylcyclohexanones are reduced in the rabbit and excreted mainly as the glucuronides of the thermodynamically more stable forms of the corresponding methylcyclohexanols. 2. Racemic cis- and trans-2-methylcyclohexanol and 2-methylcyclohexanone are all excreted as conjugated trans-2-methylcyclohexanol. However, when the (+/-)-cis-alcohol or the (+/-)-ketone is fed, (+)-trans-2-methylcyclohexanol is excreted, whereas when the (+/-)-trans-alcohol is fed it is excreted as the (+/-)-trans-alcohol. 3. Racemic cis- and trans-3-methylcyclohexanol and 3-methylcyclohexanone are all excreted as conjugated racemic cis-3-methylcyclohexanol. cis- and trans-4-Methylcyclohexanol and 4-methylcyclohexanone are all excreted as conjugated trans-4-methylcyclohexanol. 4. The metabolic differences between the various methylcyclohexanols are explicable in terms of their conformations and of Vennesland's (1958) hypothesis of the role of NADH in dehydrogenation reactions.

Alcohols↗
PubMed1965

THE METABOLISM OF METHYLCYCLOHEXANE.

1. When [U-(14)C]methylcyclohexane is fed to rabbits (dose 2-2.5m-moles/kg. body wt.), 65% of the radioactivity is excreted in the urine as metabolites, 0.5% appears in the faeces and about 15% in the expired air, some 4-5% remaining in the body in about 60hr. after dosing. The 15% of the dose appearing in the expired air consists of unchanged methylcyclohexane (10%) and (14)CO(2) (5%). The low output of (14)CO(2) shows that reactions leading to complete oxidation of methylcyclohexane are of minor importance. 2. The main metabolite found in the urine was the glucuronide of trans-4-methylcyclohexanol which was isolated. Seven methylcyclohexanols were found in the urine as conjugated glucuronides. The amounts of these were determined by isotope dilution to be as follows: cis-2-, 0.6%; trans-2-, 1.2%; cis-3-, 11.5%; trans-3-, 10.5%; cis-4-, 2.4%; trans-4-methylcyclohexanol, 14.7%, cyclohexylmethanol, 0.3%. No 1-methylcyclohexanol was found. There was evidence also that a small amount (approx. 1%) of the hydrocarbon aromatized to benzoic acid, probably via cyclohexylmethanol and cyclohexane-carboxylic acid. 3. The pattern of hydroxylation and the various amounts of the isomers found suggest that the hydroxylation in vivo of methylcyclohexane is dependent on steric factors in the molecule, hydroxylation occurring to the greatest extent at the carbon atom furthest away from the methyl group.

Alcohols↗