RESUMO
A C-glucoside of cholic acid was synthesized by the introduction of an acetyl group at position 3 alpha and direct one-pot C-glucosidation using 2,3,4,6-tetra-O-benzyl-alpha-D-glucopyranosyl chloride.
Assuntos
Ácidos Cólicos/síntese química , Fenômenos Químicos , Química , Glucosídeos/síntese química , Estrutura MolecularRESUMO
Hydration via hydroboration of 5 alpha-ergost-8-en-3 beta-ol affords 5 alpha-ergostane-3 beta, 15 alpha-diol, 5 alpha, 14 beta-ergostane-3 beta, 15 beta-diol, and 5 alpha-ergostane-3 beta, 7 beta-diol, and not 5 alpha, 9 beta-ergostane-3 beta, 7 beta-diol, as previously reported by others.
Assuntos
Ergosterol/análogos & derivados , Boranos , Boroidretos , Fenômenos Químicos , Química , Cromatografia , Ergosterol/síntese química , Ergosterol/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética , Oxirredução , EstereoisomerismoRESUMO
Formaldehyde is added to milk in the production of grana cheese as an antimicrobial agent. In order to study the fate of the formaldehyde, a grana cheese preparation was made using 14C-labelled formaldehyde. The 14C-activity in the cheese was found to be mainly associated with the caseins, but it was not uniformly distributed among the different fractions (alpha s, beta- and gamma-caseins). gamma-Casein, separated by electrophoresis, was the most reactive component showing the highest specific activity. In the gamma-casein fractions, 99% of 14C-activity was associated with the basic amino acids. The only radioactive reaction product present in the gamma-casein fraction was identified by HPTLC and by an amino acid analyser to be spinacine, a condensation product of formaldehyde and histidine. Using the same method, other unknown radioactive products, of much less relevance, were detected in the total casein hydrolysate.
Assuntos
Caseínas/metabolismo , Queijo , Formaldeído/metabolismo , Imidazóis/análise , Piridinas/análise , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Cromatografia em Camada FinaRESUMO
5,7-Cholestadien-3 beta-ol was transformed into 14 beta-cholesta-5,7-dien-3 beta-ol in six steps. The inversion of the stereochemistry at C-14 was obtained by a selective protection of the delta 5 and the elaboration of the delta 7 double bond.
Assuntos
Colestadienóis/síntese química , Desidrocolesteróis/síntese química , Fenômenos Químicos , Química , Métodos , EstereoisomerismoRESUMO
Hydroboration of 5 alpha-cholest-8-ene, 5 alpha,14 beta-cholest-8-ene and 5 alpha,14 beta-cholest-7-ene provides a simple route to oxygenated steroids with 14 beta- and 8 alpha,14 beta- unnatural stereochemistry.
Assuntos
Alcenos/metabolismo , Esteroides/síntese química , Boro , Fenômenos Químicos , Físico-Química , Colestanos/síntese química , Hidrogênio , EstereoisomerismoRESUMO
Interest in the quantitative analysis of flavouring agents in alcoholic beverages arises from the possible toxicological consequences deriving from their use. The method reported here, based on gas chromatography with selected-ion monitoring mass spectrometry (SIM), allows the simultaneous measurement of alpha, beta-thujone, pulegone, safrole, coumarin and beta-asarone at the ppb level in alcoholic beverages.
Assuntos
Bebidas Alcoólicas/análise , Anisóis/análise , Cumarínicos/análise , Dioxóis/análise , Aromatizantes/análise , Mentol/análogos & derivados , Monoterpenos , Safrol/análise , Terpenos/análise , Derivados de Alilbenzenos , Monoterpenos Bicíclicos , Monoterpenos Cicloexânicos , Cromatografia Gasosa-Espectrometria de Massas , Mentol/análiseAssuntos
Colesterol 7-alfa-Hidroxilase/metabolismo , Resina de Colestiramina/farmacologia , Microssomos Hepáticos/enzimologia , Esteroide Hidroxilases/metabolismo , Animais , Cricetinae , Feminino , Cobaias , Humanos , Cinética , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Ratos , Especificidade da EspécieRESUMO
Identification of radioactive 5 alpha-cholest-8(14)-ene-3 beta,7 alpha-diol in extracts obtained from incubations of 3 beta-hydroxy-5 alpha-[7-3H]cholest-7-ene-14 alpha-carbaldehyde with rat liver microsomes is reported. Levels of this diol in incubations of the 14 alpha-[32-3H]carbaldehyde were measured by multiple selected ion monitoring and were found to be of the same order of those of [3H]formate released from the substrate during the removal of the C-32 atom. The results demonstrate that the diol does not originate from known intermediates of cholesterol biosynthesis, i.e. 5 alpha-cholesta-7,14-dien-3 beta-ol, 5 alpha-cholest-7-en-3 beta-ol and from 5 alpha-cholest-8(14)-en-3 beta-ol. Functionalization at position 7 in the metabolism of 3 beta-hydroxy-5 alpha-cholest-7-ene-14 alpha-carbaldehyde suggests the direct involvement of the double bond in the elimination of the 14 alpha-formyl group in the biosynthetic pathway from lanosterol to cholesterol. 5 alpha-Cholest-8(14)-en-3 beta-ol appears not to be involved in the metabolism of the 14 alpha-carbaldehyde.
Assuntos
Colesterol/biossíntese , Microssomos Hepáticos/metabolismo , Aerobiose , Animais , Fenômenos Químicos , Química , Colestenos/metabolismo , Remoção de Radical Alquila , Cromatografia Gasosa-Espectrometria de Massas , RatosRESUMO
Treatment of pregnant rats with AY-9944, a drug interfering with the last steps of cholesterol biosynthesis, accumulated cholesterol precursors in brain and liver of newborn animals. Different sterol profiles were found in these organs. Along with cholesterol and cholesta-5,7-dien-3 beta-ol, present in both tissues, liver was found to contain a hitherto unreported sterol, absent in brain. The structure of cholesta-5,8-dien-3 beta-ol was attributed to this compound by mass spectrometric, 1H, and 13C NMR analysis.
Assuntos
Encéfalo/metabolismo , Colestadienóis/metabolismo , Cicloexanos/farmacologia , Fígado/metabolismo , Dicloridrato de trans-1,4-Bis(2-clorobenzaminometil)ciclo-hexano/farmacologia , Animais , Encéfalo/efeitos dos fármacos , Fenômenos Químicos , Química , Colesterol/metabolismo , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Fígado/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Troca Materno-Fetal/efeitos dos fármacos , Gravidez , RatosRESUMO
[12-14C] Dodecanoyl-CoA and [8-14C] octanoyl-CoA were tested as substrates for shortening the chain by two carbon atoms using both the 105,000 x g soluble fraction and the sonicated mitochondrial fraction of rat liver homogenate as the enzyme source. Both substrates were metabolized by the cytoplasmic enzymes giving rise to the accumulation of intermediates of the beta-oxidation process without formation of two carbon units from the methyl carbon of the acyl residue. A new method is described which allows quantitative estimation of volatile fatty acids formed by beta-oxidation of dodecanoyl- and octanoyl- Coenzyme A.