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Showing papers on "Nickel boride published in 1993"


Journal ArticleDOI
TL;DR: In this paper, a tentative mechanism involving an oxidative addition-reductive elimination sequence via a nickel hydride intermediate was proposed for the deuteration of deuterated products from organosulfur compounds.
Abstract: A variety of organosulfur compounds containing alkylthio and arylthio groups underwent reductive desulfurization under notably mild conditions when treated with nickel boride, generated in situ from nickel chloride hexahydrate and sodium borohydride in methanol-THF (3:1). Phenyl, chloro, and ester groups are not reduced under these conditions, while iodo, bromo, nitrile, aldehyde, ketone, cyclopropane, and olefinic functions are reduced either completely or partially. Deuterium-labeling studies indicate that the hydrogen that is incorporated into the product originates from both the sodium borohydride and the protic solvent, suggesting the intermediacy of dihydrogen. The epimers 3[alpha]- and 3[beta]-(phenylthio)cholestane afforded 3[alpha]- and 3[beta]-deuteriocholestane, respectively, demonstrating that the reaction proceeds with retention of configuration. The method may thus be employed for the stereospecific preparation of deuterated products from organosulfur compounds. Arguments are presented in support of a tentative mechanism involving an oxidative addition-reductive elimination sequence via a nickel hydride intermediate. 44 refs., 2 tabs.

97 citations


Journal ArticleDOI
TL;DR: Nickel boride has been used for desulphurization of sulphur-rich geomacromolecules in polar and asphaltene fractions as discussed by the authors.

74 citations


Journal ArticleDOI
TL;DR: Nickel boride smoothly reduces aryl nitro compounds to the corresponding anilines in the presence of iodo and ortho carboalkoxy groups in contrast to the problematic reductions by other methods.

30 citations


Journal ArticleDOI
TL;DR: In this article, the reaction of aryl-lead triacetates with 3-(phenylthio)-chroman-4-one and 2-p -methoxyphenyl-3-phenyl-thio-chroman 4-one derivatives was carried out in chloroform in presence of pyridine.

28 citations


Journal ArticleDOI
TL;DR: Boriding can be used to create a hard, tough surface "case" on nickel alloys, extending the application of these materials into more severe environments as discussed by the authors, where the case layer is a complex nickel boride layer.

8 citations


Journal ArticleDOI
TL;DR: In this article, a tentative mechanism involving an oxidative addition-reductive elimination sequence via a nickel hydride intermediate was proposed for the deuteration of deuterated products from organosulfur compounds.
Abstract: A variety of organosulfur compounds containing alkylthio and arylthio groups underwent reductive desulfurization under notably mild conditions when treated with nickel boride, generated in situ from nickel chloride hexahydrate and sodium borohydride in methanol-THF (3:1). Phenyl, chloro, and ester groups are not reduced under these conditions, while iodo, bromo, nitrile, aldehyde, ketone, cyclopropane, and olefinic functions are reduced either completely or partially. Deuterium-labeling studies indicate that the hydrogen that is incorporated into the product originates from both the sodium borohydride and the protic solvent, suggesting the intermediacy of dihydrogen. The epimers 3[alpha]- and 3[beta]-(phenylthio)cholestane afforded 3[alpha]- and 3[beta]-deuteriocholestane, respectively, demonstrating that the reaction proceeds with retention of configuration. The method may thus be employed for the stereospecific preparation of deuterated products from organosulfur compounds. Arguments are presented in support of a tentative mechanism involving an oxidative addition-reductive elimination sequence via a nickel hydride intermediate. 44 refs., 2 tabs.

2 citations



Journal ArticleDOI
TL;DR: Nickel boride smoothly reduces aryl nitro compounds to the corresponding anilines in the presence of iodo and ortho carboalkoxy groups in contrast to the problematic reductions by other methods as discussed by the authors.
Abstract: Nickel boride smoothly reduces aryl nitro compounds to the corresponding anilines in the presence of iodo and ortho carboalkoxy groups in contrast to the problematic reductions by other methods.

1 citations


Journal ArticleDOI
TL;DR: In this article, the reaction of aryl-lead triacetates with 3-(phenylthio)-chroman-4-one and 2-p -methoxyphenyl-3-phenyl-thio-chroman 4-one derivatives was carried out in chloroform in presence of pyridine.
Abstract: The reaction of aryllead (IV) triacetates with 3-(phenylthio)-chroman-4-one and 2- p -methoxyphenyl-3-(phenylthio)-chroman-4-one derivatives was carried out in chloroform in presence of pyridine to afford moderate to quantitative yields of the corresponding hindered 3-aryl-3-phenylthiochroman-4-one derivatives. Removal of the phenylthio group by oxidation with dimethyldioxirane led to the corresponding isoflavones and 2- p -methoxyphenylisoflavones, and by reduction with a large excess of nickel boride to the isoflavanones and 2-(4′-anisyl)-isoflavanones respectively. In the 2- p -methoxyphenyl series the nickel boride reduction of the compounds bearing ortho -substituted 3-aryl groups gave the chalcones which were recyclised under basic catalysis.