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2. Occurrence and Toxicity of Disinfection Byproducts in European Drinking Waters in Relation with the HIWATE Epidemiology Study

Author

Jeong, Clara H., primary, Wagner, Elizabeth D., additional, Siebert, Vincent R., additional, Anduri, Sridevi, additional, Richardson, Susan D., additional, Daiber, Eric J., additional, McKague, A. Bruce, additional, Kogevinas, Manolis, additional, Villanueva, Cristina M., additional, Goslan, Emma H., additional, Luo, Wentai, additional, Isabelle, Lorne M., additional, Pankow, James F., additional, Grazuleviciene, Regina, additional, Cordier, Sylvaine, additional, Edwards, Susan C., additional, Righi, Elena, additional, Nieuwenhuijsen, Mark J., additional, and Plewa, Michael J., additional

Published
2012
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4. Concentration, Chlorination, and Chemical Analysis of Drinking Water for Disinfection Byproduct Mixtures Health Effects Research: U.S. EPA’s Four Lab Study

Author

Pressman, Jonathan G., primary, Richardson, Susan D., additional, Speth, Thomas F., additional, Miltner, Richard J., additional, Narotsky, Michael G., additional, Hunter, III, E. Sidney, additional, Rice, Glenn E., additional, Teuschler, Linda K., additional, McDonald, Anthony, additional, Parvez, Shahid, additional, Krasner, Stuart W., additional, Weinberg, Howard S., additional, McKague, A. Bruce, additional, Parrett, Christopher J., additional, Bodin, Nathalie, additional, Chinn, Russell, additional, Lee, Chih-Fen T., additional, and Simmons, Jane Ellen, additional

Published
2010
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6. Occurrence and Mammalian Cell Toxicity of Iodinated Disinfection Byproducts in Drinking Water

Author

Richardson, Susan D., primary, Fasano, Francesca, additional, Ellington, J. Jackson, additional, Crumley, F. Gene, additional, Buettner, Katherine M., additional, Evans, John J., additional, Blount, Benjamin C., additional, Silva, Lalith K., additional, Waite, Tim J., additional, Luther, George W., additional, McKague, A. Bruce, additional, Miltner, Richard J., additional, Wagner, Elizabeth D., additional, and Plewa, Michael J., additional

Published
2008
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7. Integrated Disinfection By-Products Mixtures Research: Comprehensive Characterization of Water Concentrates Prepared from Chlorinated and Ozonated/Postchlorinated Drinking Water

Author

Richardson, Susan D., primary, Thruston, Alfred D., additional, Krasner, Stuart W., additional, Weinberg, Howard S., additional, Miltner, Richard J., additional, Schenck, Kathleen M., additional, Narotsky, Michael G., additional, McKague, A. Bruce, additional, and Simmons, Jane Ellen, additional

Published
2008
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25. Characterization and sources of extractable organochlorine in white sucker downstream from bleached kraft pulp mills.

Author

Wenshan Zhuang, McKague, A. Bruce, Reeve, Douglas W., and Carey, John

Subjects
*ORGANOCHLORINE compounds, *ACETONE, *WHITE sucker, *FATTY acids, *CHLORINE
Abstract

Organochlorine, obtained by extraction with hexane–acetone mixture (3  :  1) of fillets of white sucker ( Catostomus commersoni ) sampled downstream of pulp mills and in a reference river, was characterized by gel-permeation chromatography, transesterification, neutron activation analysis, and gas chromatography with halogen-sensitive detection. It was found that over 78% of the extractable organochlorine (EOCl) is of relatively high molecular weight (>∼⃒350). Chlorinated fatty acids account for 43–80% of EOCl in the high-molecular-weight portion, while chlorobenzenes, chlorinated pesticides, and polychlorinated biphenyls account for 4–55% of EOCl in the low-molecular-weight portion. Though undetectable in reference fish, three particular chlorinated fatty acids, i.e. threo -5,6-dichlorotetradecanoic, threo -7,8-dichlorohexadecanoic and threo -9,10-dichlorooctadecanoic acids, are characteristic of EOCl from fish collected downstream of bleached kraft pulp mills using chlorine-based bleaching, representing about 30% of total EOCl, of which threo -5,6-dichlorotetradecanoic acid alone accounts for 60–70%. It is thus evident that, among chlorinated compounds discharged from bleached kraft pulp mills, threo -9,10-dichlorooctadecanoic acid, presumably generated in chlorine-based bleaching processes, is the most bio-accumulative in fish and can be biodegraded by fish into dichlorohexadecanoic and dichlorotetradecanoic acids, presumably via β-oxidative metabolism. These three compounds were also identified in suspended solids isolated from biologically treated final effluent discharged from a bleached pulp mill using 50% ClO 2 substitution, thus confirming the effluent-related source for downstream fish. The finding also suggests that β-oxidation of dichlorooctadecanoic acid may also be operative in micro-organisms. [ABSTRACT FROM AUTHOR]

Published
2006
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30. Synthetic studies of indole alkaloids

Author

McKague, Allan Bruce

Abstract

Two synthetic approaches to the Aspidosperma and Iboga classes of indole alkaloids are described. Section A discusses a possible synthetic route to the nine-membered ring alkaloid quebrachamine (93a). Nicotinic acid (75) was reduced to nipecotic acid hydrochloride (76), which was esterified to yield methyl nipecotate (77). Attempted preparation of 3-carbomethoxy-3-ethylpiperidine (67) by alkylation of (77) or of its p-bromobenzamide derivative (78) was unsuccessful„ The substituted piperidine (67) was then prepared by another synthetic sequence. Alkylations of methyl cyanoacetate led to methyl 3-chloropropylethylcyanoacetate (83). Catalytic reduction of the latter nitrile to the corresponding amine allowed cyclization to 3-carbomethoxy-3-ethylpiperidine (67). Reaction of 67 with 2-carboethoxy-3-(β-chloroethyl)-indole (66) provided 2-carboethoxy-3-[β-(3-carbomethoxy-3-ethyl-N-piperidyl)-ethyl]-indole (68). Attempted acyloin condensation of the latter to a nine-membered ring compound (69) was unsuccessful and led only to hydrolysis products. Section B describes the first total synthesis of the nine-membered ring compounds 4α- and 4β- dihydrocleavamine (152) and (153), isomeric with quebrachamine. Conversion of 2-ethyl 1,3-propanediol (106) to the monobenzyl ether (107) followed treatment with thionyl chloride provided 3-benzyloxy-2-ethyl- propyl chloride (108). Alkylation of malonic ester with the latter afforded diethyl 3-benzyloxy-2-ethylpropylmalonate (109 ). A second alkylation of 109 with ethyl bromoacetate yielded diethyl 2-(2-benzyloxymethylbutyl)-2-carboethoxysuccinate (113 ). Hydrolysis, decarboxylation and re-esterification of this triester provided the substituted succinic ester (71a) in high yield. The succinic ester (71a) was also prepared but in low yield by hydrolysis, decarboxylation and re-esterification of the malonic ester (109) followed by alkylation with ethyl iodoacetate,, Condensation of the succinic ester (71a) with tryptamine provided the succinimide (130) which was reduced with lithium aluminum hydride to the tertiary amine (131) in high yield. Mercuric acetate oxidation of the latter afforded a mixture of isomeric cyclized compounds one of which was the desired benzyl ether 72a. Catalytic debenzylation yielded the corresponding aminoalcohol (149) which was converted to the quaternary mesylate (73a) by treatment with methanesulfonyl chloride. Reductive cleavage of 73a with sodium in liquid ammonia yielded 4α- and 4β- dihydrocleavamine. The synthesis of the isomeric dihydrocleavamines coupled with other synthetic work provides a general entry into the Aspidosperma and Iboga alkaloids.

Published
1967
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