RESUMO
The crystal structure of the title compound, C(10)H(20)O(2), was published [Korner et al. (2000). Acta Cryst. C56, 74-75] with an erroneous position for an hydroxy H atom. This has now been corrected and leads to a more sensible hydrogen-bonding scheme.
RESUMO
In an attempt to improve the industrial manufacture of corticoids starting from desoxycholic acid, two major tasks had to be accomplished: (1) selective transposition of a 12 alpha-oxygen function to the 11-position. (2) Degradation of the side chain by three carbon atoms. The most convenient solution to the first problem included protection of the 3 alpha-hydroxyl, then dehydrating the 12 alpha-alcohol via its mesylate, and treatment of the resulting delta 11-12-alkene with PDC and iodine, to obtain the 12 alpha-iodo-11-ketone in very high yield. After reductive dehalogenation and saponification, the resulting acid proved to be suitable for solving our second problem. Oxidative decarboxylation with lead tetraacetate leads to an olefin, the double bond of which could be shifted along the side chain to produce the corresponding delta 20-22-isomer. Ozonolytic cleavage of the C--C double bond in this position made the 20-ketone 19 readily accessible. The latter plays a key role in the production of various corticoid drugs, since most of them are derived from this very compound, e.g. cortisol.
Assuntos
Corticosteroides/síntese química , Indicadores e Reagentes , Espectroscopia de Ressonância Magnética , Rotação Ocular , Relação Estrutura-AtividadeRESUMO
Four duplicate samples of cocoa-containing materials, a practice sample, and standards were submitted to the collaborators for theobromine and caffeine analysis by HPLC. In the method the samples are defatted with petroleum ether, and dried. The fat-free residue is then extracted with water and an aliquot is injected into the chromatograph. Compounds are quantitated by comparison with internal or external standards, either by peak height or peak area. Results for all the analyses showed that few of the values were more than 2 standard deviations from the mean. The method has been adopted as official first action.
Assuntos
Cacau/análise , Cafeína/análise , Teobromina/análise , Cromatografia Líquida de Alta Pressão , Controle de QualidadeRESUMO
A method was developed for determining theobromine and caeffine in cocoa and chocolate products by high pressure liquid chromatography. After a simple hot water extraction, both theobromine and caffeine were separated by using a reverse phase C18 column and a mobile phase of methanol-water-acetic acid (20 + 79 + 1). Theobromine and caffeine were quantitated at 280 nm; average recoveries were 98.7 and 95.0%; and coefficients of variation were 2.31 and 3.91%, respectively.
