969 resultados para p-menth-3-ene-1,2,8-triol


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Compounds containing the pyrrolidine moiety are key substructures of compounds with biological activity and organocatalysts. In particular, annulated chiral pyrrolidines with alpha stereogenic centers have aldostereone synthase inhibition activity. In addition, 5-substituted pyrroloimidazol(in)ium salts precursors to N-heterocyclic carbene (NHC) precatalysts are rare due to a lack of convenient synthetic routes to access them. In this thesis is described a rapid synthesis of NHC precursors and a possible route to 5-substituted pyrroloimidazole biologically active compounds. The method involves the preparation of chiral saturated and achiral unsaturated pyrrolo[I,2- c]imidazol-3-ones from N-Cbz-protected t-Butyl proline carboxamide. The resulting starting materials may be used to prepare the target chiral annulated imidazol(in)ium products by a two-step sequence involving first stereoselective lithiation-substitution, followed by POCh induced salt formation.

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Survey map of the Second Welland Canal created by the Welland Canal Company showing a portion of the Grantham Township near Port Dalhousie. Identified structures associated with the Canal include the new towing path. The surveyors' measurements and notes can be seen in red and black ink and pencil. Features of the First Welland Canal are noted in red ink and include the old Lock 2, old towing path and the original bed of the Twelve Mile Creek. Local area landmarks are also identified and include streets and roads (ex. Side Line and Old Road), four unnamed bridges, and a tree stump along the old towing path. A New Road to Port Dalhousie is featured in red ink. Properties and property owners of note are: Concession 3 Lots 21, 22 and 23, Concession 4 Lots 21, 22 and 23, Jabez Johnson, Adam Gould, Peter Weaver and Samuel Wood.

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A blueprint produced by Westinghouse Electric & MFG. Co. in Pittsburgh, Pennsylvanna. The blueprint is dated 19 August 1903 and is stamped "OBSOLETE".

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This thesis describes a method involving the preparation of an L-proline-derived imidazolone protected with an N-triethylsilyl group that undergoes diastereoselective lithiation followed by electrophile quench to give C5-substituted products with syn stereochemistry. The N-silylated derivatives may be more easily N-deprotected as compared to previous N-t-Bu analogues to give secondary ureas. These may serve as precursors to N-phenyl chiral bicyclic guanidines or as NHC precursors for synthesis of corresponding complexes.

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This thesis describes a method involving the preparation of an L-proline-derived imidazolone protected with an N-triethylsilyl group that undergoes diastereoselective lithiation followed by electrophile quench to give C5-substituted products with syn stereochemistry. The N-silylated derivatives may be more easily N-deprotected as compared to previous N-t-Bu analogues to give secondary ureas. These may serve as precursors to N-phenyl chiral bicyclic guanidines or as NHC precursors for synthesis of corresponding complexes.

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Estimate of work done on the Port Dalhousie and Thorold Railway by Messrs. Brown and McDonell, contractors, on sections 1, 2, and 3 ending at St. Catharines for the month of Sept. 1854, signed by S.D. Woodruff, Oct. 1854.

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Estimate of work done on the Port Dalhousie and Thorold Railway by Messrs. Brown and McDonell, contractors, on sections 1, 2, and 3 ending at St. Catharines during the month ending Oct. 31, 1854.

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Estimate of work done on the Port Dalhousie and Thorold Railway by Messrs. Brown and McDonell, contractors, on sections 1, 2, and 3 ending at St. Catharines for the month of Oct. 1854, signed by S.D. Woodruff, Nov. 1854.

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Chart of estimate of work done on the Port Dalhousie and Thorold Railway by Messrs. Brown and McDonell, contractors, on sections 1, 2, and 3 ending at St. Catharines for the month ending Dec. 1, 1854, signed by S.D. Woodruff, Jan. 1855.

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Scrap of paper that has been burned almost completely. Only the header of the document is intact. It is an estimate of work done by Messrs. Brown and McDonell, contractors on sections 1, 2 and 3 ending at St. Catharines for the months of April and May 1855.

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Chart of estimate of work done on the Port Dalhousie and Thorold Railway by Messrs. Brown and McDonell, contractors, on sections 1, 2, and 3 ending at St. Catharines for the month of Oct., 1855. This document is water damaged and full of holes. The list of prices is almost completely illegible. The document is signed by S.D. Woodruff, Nov. 1855.

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Schedule of prices for Brown and McDonell, contractors, for sections 1, 2 and 3 of the Port Dalhousie Thorold Railway (1 page, handwritten), Sept. 24, 1856.

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Chart of land drainage for the Welland Canal final estimate of work done on sections no.1, 2 and 3 on the road below lock no. 2 leading to Port Dalhousie. Work commenced Nov. 1846 and finished July 1847. Road work and the waste weir no.1 to Port Dalhousie work commenced Aug. 1847 and finished Sept. 1847, Nov.1, 1847.

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Tesis (Maestría en Ciencias con Especialidad en Ingeniería Cerámica) UANL

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Résumé Cette thèse consiste en trois thèmes résumés dans les paragraphes ci-dessous. L’influence de différents groupements protecteurs du groupe hydroxyle lors des réactions d’ouverture des cis- et trans- 3-hydroxy-1,2-époxycycloalcanes a été étudiée. Il a été montré que Yb(OTf)3 constituait un catalyseur doux pour l’ouverture régiosélective de cycles afin d’obtenir les -anilino cycloalcanols correspondants avec de bons rendements. Le chauffage du milieu réactionnel dans le toluène comme solvant a permis d’augmenter la cinétique de la réaction, au dépend du rendement. La partie aniline a été régiosélectivement introduite en position vicinale du groupe hydroxyle ou éther afin d’obtenir un unique régioisomère. La même tendance a été observée avec les époxydes du 3-azidocyclohex-1-ène et du 3-carbamate correspondant. Le temps de réaction a été réduit lorsque Yb(OTf)3 a été dissous dans l’acétonitrile. Le triflate d’ytterbium (III) a également été utilisé comme catalyseur pour l’ouverture de cycle régiosélective d’aziridines non-activées sur des cyclohexanes portant des substituants azotures ou éthers de benzyle. L’ion azoture ou l’aniline forment les produits trans correspondants, donnant alors accès à des diamines vicinales avec de bons rendements. Un éther ω-alcoxy p-méthoxybenzylique racémique, inhibiteur de HDAC, a été ainsi préparé en huit étapes synthétiques (rendement total de 26%) à partir du 1-((tert-butyldiphénylsilyl)oxy)hept-6-èn-2-ol. Ceci représente un progrès par rapport à la précédente méthode (9 étapes, rendement total de 16%). La métathèse croisée se montre particulièrement efficace et pratique dans cette stratégie et l’alkylation par le trichloroacétimidate de p-méthoxybenzyle en présence de Sc(OTf)3 améliore le rendement global de la synthèse. Un aminoalcool présent dans la pactamycine et contenant le squelette carboné, les groupements fonctionnels et la stéréochimie requise a été synthétisé en 27 étapes à partir de la L-thréonine. La méthodologie décrite dans cette thèse permet la synthèse de cet intermédiaire clé à l’échelle multigramme.