Synthesis and Hepatic Metabolism of Xanthobilirubinic Acid Regioisomers
摘要:
A set of four regioisomeric dipyrrinone propionic acids has been synthesized and their hepatic metabolism examined in rats: xanthobilirubinic acid and pseudo-xanthobilirubinic acid each with a propionic acid on a pyrrole ring; exo-psi-xanthobilirubinic acid and endo-psi-xanthobilirubinic acid, each with a propionic acid transposed to a lactam ring. After intravenous injection all four isomers were excreted to some degree in unchanged form in bile in normal rats. Xanthobilirubinic acid, the structurally closest dipyrrinone to bilirubin, and exo-psi-xanthobilirubinic acid were excreted almost entirely in unchanged form. However, a small fraction of xanthobilirubinic acid acyl glucuronide was also detected. More extensive acyl glucuronidation was observed for pseudo-xanthobilirubinic acid, and endo-psi-xanthobilirubinic acid underwent slow metabolism to unidentified more polar products that did not seem to be glucuronides.
A new methodology for the preparation of 2-cyanopyrroles and synthesis of porphobilinogen
作者:Maciej Adamczyk、Rajarathnam E. Reddy
DOI:10.1016/0040-4020(96)00941-6
日期:1996.11
Condensation of α-acetoxynitro compounds 4a-f with isocyanoacetonitrile (5) using DBU in THF afforded 2-cyano-3,4-substituted pyrroles 6a-f, in good yield. Porphobilinogen (PBG, 12), the key building block for the preparation of tetrapyrrolic natural products, was synthesized from 2-cyano-3,4-substituted pyrrole 6f, in four steps.
Synthesis of unsaturated silyl nitronates via the silylation of conjugated nitroalkenes
作者:Elizaveta A. Khotyantseva、Andrey A. Tabolin、Roman A. Novikov、Yulia V. Nelyubina、Sema L. Ioffe
DOI:10.1016/j.tetlet.2018.07.011
日期:2018.8
A new method for the synthesis of conjugated silyl nitronates from nitroalkenes is described. The procedure has wide substrate scope and is compatible with in situ generation of the substrates from 2-nitroalcohols or 2-chloro-nitroalkanes. A cascade transformation to give 3,4,5,6-tetrahydropyridine N-oxide derivatives was disclosed.
作者:Derek H.R. Barton、Jocelyne Kervagoret、Samir Z. Zard
DOI:10.1016/s0040-4020(01)89069-4
日期:1990.1
A convenient synthesis of 2-Cyanopyrroles from isocyanoacetonitrile
作者:Maciej Adamczyk、Rajarathnam E. Reddy
DOI:10.1016/0040-4039(95)01724-v
日期:1995.10
2-Cyano-3,4-substituted pyrroles 2a-e, important intermediates in the synthesis of porphyrins and related compounds, were prepared via base promoted condensation of alpha-acetoxynitro compound 1 alpha-e with isocyanoacetonitrile (3) in THF, in good yield.
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