7 resultados para 1,2-DIHYDROXY-9,10-ANTHRACENEDIONE

em Brock University, Canada


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The effects of sample solvent composition and the injection volume, on the chromatographic peak profiles of two carbamate derivatives, methyl 2-benzimidazolecarbamate (MBC) and 3-butyl-2,4-dioxo[1,2-a]-s-triazinobenzimidazole (STB), were studied using reverse phase high performance liquid chromatograph. The study examined the effects of acetonitrile percentage in the sample solvent from 5 to 50%, effects of methanol percentage from 5 to 50%, effects of pH increase from 4.42 to 9.10, and effect of increasing buffer concentration from ° to 0.12M. The effects were studied at constant and increasing injection mass and at four injection volumes of 10, 50, 100 and 200 uL. The study demonstrated that the amount and the type of the organic solvents, the pH, and the buffer strength of the sample solution can have a pronounced effect on the peak heights, peak widths, and retention times of compounds analysed. MBC, which is capable of intramolecular hydrogen bonding and has no tendency to ionize, showed a predictable increase .in band broadening and a decrease in retention times at higher eluting strengths of the sample solvent. STB, which has a tendency to ionize or to strongly interact with the sample solvent, was influenced in various ways by the changes in ths sample solvent composition. The sample solvent effects became more pronounced as the injection volume increased and as the percentage of organic solvent in the sample solution became greater. The peak height increases for STB at increasing buffer concentrations became much more pronounced at higher analyte concentrations. It was shown that the widely accepted procedure of dissolving samples in the mobile phase does not yield the most efficient chromatograms. For that reason samples should be dissolved in the solutions with higher aqueous content than that of the mobile phase whenever possible. The results strongly recommend that all the samples and standards, regardless whether the standards are external or internal, be analysed at a constant sample composition and a constant injection volume.

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Survey map of the Second Welland Canal created by the Welland Canal Company showing a portion of the Grantham Township sometimes referred to as the Welland Vale. Identified structures associated with the Canal include Lock 2, several weirs, and the Lock Tender's House. 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 towing path and the Old Canal itself. Local area landmarks and businesses are also identified and include streets and roads (ex. Side Line and Old Road to Port Dalhousie), J. C. Clark's Ice House, J. L. Ranney Store House, a burnt mill, barrel shed, a building leased to Michael Kerrins, and a number of unidentified structures (possibly houses or cabins) belonging to D. Cain, R. Cain, W. Weaver and W. Huddy. A New Road to St. Catharines is featured in red ink. Properties and property owners of note are: Concession 5 Lots 20, 21 and 22, Concession 6 Lots 20 and 21, Thomas Adams, John Gould, George Rykert, Theophilus Mack, William H. Merritt, J. L. Ranney, and the Board of Works.

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Survey map of the Second Welland Canal created by the Welland Canal Company showing the Grantham Township between the Town of St. Catharines and Merritton. Identified structures associated with the Canal include Locks 9 and 10, waste weirs, the towing path, a 2nd towing path, and the Canal waterway itself. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include roads (ex. Road to Centreville), hydraulic race, and the Centreville Mill. Properties and property owners of note are: Concession 8 Lots 12 and 12, Lewis Traver, Richard Ash, John Bradley, Owen Clifford, Orson Phelps, C. Bradley, the W. C. Loan Company, and T. Towers Mill Lot.

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Rates of H2 formation have been determined for the thermal decomposition of isopropyl peroxide at l30o-l50oC in toluene and methanol and at l400C in isopropyl alcohol and water. Product studies have been carried out at l400C in these solvents. The decomposition of isopropyl peroxide was shown to be unimolecular with energies of activation in toluene, and methanol of 39.1, 23.08 Kcal/mole respectively. It has been shown that the rates of H2 formation in decomposition of isopropyl peroxide are solvent dependent and that the ~ vs "'2';' values (parameters for solvent polarity) givesastraight line. Mechanisms for hydrogen production are discussed which satisfactorily explain the stabilization of the six-centered transition state by the solvent. One possibility is that of conformation stabilization by solvent and the other, a transition state with sufficient ionic character to be stabilized by a polar solvent. Rates of thermal decomposition of 1,2-dioxane in tert-butylbenzene at l40o-l70oC have been determined. The activation energy was found to be 33.4 Kcal/mole. This lower activation energy, compared to that for the decomposition of isopropyl peroxide in toluene (39.1 Kcal/mole) has been explained in terms of ring strain. Decomposition of 1,2 dioxane in MeOH does not follow a first order reaction. Several mechanisms have been suggested for the products observed for decomposition of 1;2-dioxane in toluene and methanol.

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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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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 during the month ending Oct. 31, 1854.