Bis-[13CO2H]-mesobilirubin-XIIIα was synthesized in 11% overall yield in 10 steps from 99% enriched K13CN. The synthetic methods are adapted to a scale of a few grams to a few milligrams.
Synthesis and acidity constants of 13CO2H-labelled mono and dipyrrole carboxylic acids. pKa from 13C-NMR
作者:Darren L. Holmes、David A. Lightner
DOI:10.1016/0040-4020(94)01052-2
日期:1995.2
[1-13C]-phenylacetic (2) acids were determined to be 4.60 and 4.16 respectively in H2O, and 4.67 and 4.31 respectively in H2O-27% vol (CD3)2SO. Bilirubin analogs, xanthobilirubic acid (5) and nor-xanthobilirubic acid (6) were determined to have pKa values of 4.76 and 4.64 respectively in H2O-27% vol (CD3)2SO, and extrapolated to pKa values ∼4.62 and 4.51 in H2O.
Heteronuclear NOE analysis of bilirubin solution conformation and intramolecular hydrogen bonding
作者:Thomas Dörner、Bernd Knipp、David A. Lightner
DOI:10.1016/s0040-4020(97)00045-8
日期:1997.2
analogs (1–5) in CDCl3 and in CDCl3-(CD3)2SO solutions indicate that the carboxylic acid groups and dipyrrinone lactams and/or pyrroles are linked by intramolecular hydrogen bonding. Nonbonded C-H to H-C and N-H to H-N, and N-H to CO2H distances were calculated from the NOE data and confirm that the bilirubins adopt a folded, ridge-tile shape in solution.
在CDCl 3和CDCl 3-(CD 3)2 SO溶液中对胆红素类似物(1-5)进行的1 H 1 H}-单核和13 C 1 H}-异核NOE(核劳累效应)实验表明羧酸基和二吡啶酮内酰胺和/或吡咯是通过分子内氢键连接的。从NOE数据计算出未键合的CH与HC之间的距离以及NH与HN之间的距离以及NH与CO 2 H之间的距离,并证实胆红素在溶液中呈折叠的,脊状的瓦状形状。