- Functionalized α-oximinoketones as building blocks for the construction of imidazoline-based potential chiral auxiliaries
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Functionalized α-oximinoketones with β-alkoxy, β-alkyl, and β-sulfenyl groups were used as efficient synthons for the preparation of chiral 1-acyl-4-imidazolin-2-ones and 1-acylimidazolidin-2-ones. For the preparation of the former heterocycles, α-oximinoketones were transformed into their respective imidazole N-oxides by neutral treatment with a chiral triazine, followed by reaction with acetic or propionic anhydrides to furnish the desired chiral 1-acetyl- or 1-propionyl-4-imidazolin-2-ones in moderate overall yields. Upon palladium hydroxide-catalyzed hydrogenation, these series were converted into their corresponding 1-acylimidazolidin-2-ones in high diastereoisomeric ratios. Thus, these novel chiral 1-acetyl- and 1-propionyl-imidazolidin-2-ones were obtained with a variety of alkyl groups at the C-4 and C-5 positions of the heterocycle, through a three-step methodology, and can be applied as new potential chiral auxiliaries.
- Gutiérrez, Rsuini U.,Rebollar, Araceli,Bautista, Rafael,Pelayo, Vanessa,Várgas, José Luis,Montenegro, Mabel M.,Espinoza-Hicks, Carlos,Ayala, Francisco,Bernal, Pablo M.,Carrasco, Cuauhtemoc,Zepeda, L. Gerardo,Delgado, Francisco,Tamariz, Joaquín
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p. 230 - 246
(2015/03/04)
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- Complexes of technetium-99m with propylene amine oximes
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A family of propylene amine oxime ligands has the formula 2 STR1 wherein preferably R1 is Cl-C4 alkyl or phenyl and each of R, R2, R3 and R4 is H or Cl-C4 alkyl. The technetium-99m complexes of these ligands are lipophilic neutral complexes useful as diagnostic radiopharmaceuticals and particularly for brain scanning. The ligands show stereoisomerism. The preparation and properties of the dl- and meso-stereoisomers, and of the d- and l-enantiomers, are described. The l-enantiomer and the dl-stereoisomer of the preferred compound (2, R=R1 =R2 =CH3, R3 =R4 =H) show good retention in the brain.
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