FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W639698907> ?p ?o ?g. }

• W639698907 abstract "Oxysterols (OS), the polyoxygenated sterols, represent a class of potent regulatory molecules for important biological actions. Cytotoxicity of OS is one of the most important aspects in studies of OS bioactivities. However, studies, the structure-activity relationship (SAR) study in particular, have been hampered by the limited availability of structurally diverse OS in numbers and amounts. The aim of this project was to develop robust synthetic methods for the preparation of polyhydroxyl sterols, thereof, evaluate their cytotoxicity and establish structure-activity relationship. First, we found hydrophobicity of the side chain is essential for 7-HC's cytotoxicity, and a limited number of hydroxyl groups and a desired configuration on the A, B ring are required for a potent cytotoxicity of an OS, after syntheses and tests of a number of 7-HC's analogues against cancer cell lines. Then polyoxygenation of cholesterol A, B rings was explored. A preparative method for the synthesis of four diastereomerically pure cholest-4-en-3,6-diols was developed. Epoxidation on these cholest-4-en-3,6-diols showed that an allyl group exerts an auxiliary role in producing products with desired configuration in syntheses of the eight diastereomerically pure 45-epoxycholestane-3,6-diols. Reduction of the eight 45-epoxycholestane-3,6-diols produced all eight isomers of the cytotoxic 5α-acholestane 3β,5,6β-triol (CT) for the first time. Epoxide ring opening with protic or Lewis acids on the eight 45-epoxycholestane-3,6-diols are carefully studied. The results demonstrated a combination of an acid and a solvent affected the outcomes of a reaction dramatically. Acyl group participation and migration play an important role with numbers of substrates under certain conditions. All the eight 4,5-trans cholestane- 3,4,5,6-tetrols were synthesised through manipulation of acyl participation. Furthermore these reaction conditions were tested when a number of cholestane-3,4, 5,6,7-pentols and other C3-C7 oxygenated sterols were synthesised for the first time. Introduction of an oxygenated functional group through cholest-2-ene derivatives was studied. The elimination of 3-(4-toluenesulfonate) esters showed the interaction between the existing hydroxyls or acyls with the reaction centre often resulted in different products. The allyl oxidation, epoxidation and Epoxide ring opening reactions are investigated with these cholest-2-enes." @default.
• W639698907 created "2016-06-24" @default.
• W639698907 creator A5021412272 @default.
• W639698907 date "2002-01-01" @default.
• W639698907 modified "2023-09-24" @default.
• W639698907 title "Synthesis and cytotoxity of oxysterols:studies on the A,B ring polyoxygenated sterols" @default.
• W639698907 hasPublicationYear "2002" @default.
• W639698907 type Work @default.
• W639698907 sameAs 639698907 @default.
• W639698907 citedByCount "0" @default.
• W639698907 crossrefType "dissertation" @default.
• W639698907 hasAuthorship W639698907A5021412272 @default.
• W639698907 hasConcept C109316439 @default.
• W639698907 hasConcept C161790260 @default.
• W639698907 hasConcept C178790620 @default.
• W639698907 hasConcept C185592680 @default.
• W639698907 hasConcept C202751555 @default.
• W639698907 hasConcept C2776920199 @default.
• W639698907 hasConcept C2779515768 @default.
• W639698907 hasConcept C2780378348 @default.
• W639698907 hasConcept C2781306241 @default.
• W639698907 hasConcept C55493867 @default.
• W639698907 hasConcept C71240020 @default.
• W639698907 hasConceptScore W639698907C109316439 @default.
• W639698907 hasConceptScore W639698907C161790260 @default.
• W639698907 hasConceptScore W639698907C178790620 @default.
• W639698907 hasConceptScore W639698907C185592680 @default.
• W639698907 hasConceptScore W639698907C202751555 @default.
• W639698907 hasConceptScore W639698907C2776920199 @default.
• W639698907 hasConceptScore W639698907C2779515768 @default.
• W639698907 hasConceptScore W639698907C2780378348 @default.
• W639698907 hasConceptScore W639698907C2781306241 @default.
• W639698907 hasConceptScore W639698907C55493867 @default.
• W639698907 hasConceptScore W639698907C71240020 @default.
• W639698907 hasLocation W6396989071 @default.
• W639698907 hasOpenAccess W639698907 @default.
• W639698907 hasPrimaryLocation W6396989071 @default.
• W639698907 hasRelatedWork W118948787 @default.
• W639698907 hasRelatedWork W1576261605 @default.
• W639698907 hasRelatedWork W1814838980 @default.
• W639698907 hasRelatedWork W2015844835 @default.
• W639698907 hasRelatedWork W2046745368 @default.
• W639698907 hasRelatedWork W2048521014 @default.
• W639698907 hasRelatedWork W2054304996 @default.
• W639698907 hasRelatedWork W2069488405 @default.
• W639698907 hasRelatedWork W2083549673 @default.
• W639698907 hasRelatedWork W2091138510 @default.
• W639698907 hasRelatedWork W2124733009 @default.
• W639698907 hasRelatedWork W2134606720 @default.
• W639698907 hasRelatedWork W2140100618 @default.
• W639698907 hasRelatedWork W2150918991 @default.
• W639698907 hasRelatedWork W2288900729 @default.
• W639698907 hasRelatedWork W2366478428 @default.
• W639698907 hasRelatedWork W2517495948 @default.
• W639698907 hasRelatedWork W2949395279 @default.
• W639698907 hasRelatedWork W2950761903 @default.
• W639698907 hasRelatedWork W2010690765 @default.
• W639698907 isParatext "false" @default.
• W639698907 isRetracted "false" @default.
• W639698907 magId "639698907" @default.
• W639698907 workType "dissertation" @default.