Syntheses of Pyridine and Bipyridine Frameworks Combining Dual Fluorescent and Magnetic Probes
作者:Raymond Ziessel、Christophe Stroh
DOI:10.1021/ol034474p
日期:2003.7.1
graphic2,6-Disubstituted pyridines, 6-substituted 2,2'-bipyridines, and 6,6'-disubstituted 2,2'-bipyridines are readily prepared under mild conditions from 5-(dimethylamino)-1-naphthalenesulfonamide chloride (DANS-Cl) and chloromethyl-nitronyl nitroxide (CH2Cl-NIT) starting materials and adequately functionalized building blocks. The syntheses of the pyridine molecules bearing two radicals and a DANS fragment first required the attachment of the aliphatic radical onto an aldehyde-protected dansylated compound, followed by the construction of the second aromatic radical.
Convenient and Multistep Preparation of Oligopyridines Bearing Multiple Dansyl and Nitroxide Radicals
作者:Raymond Ziessel、Christophe Stroh
DOI:10.1055/s-2003-42083
日期:——
A series of pyridine and bipyridine molecules combining dual fluorescent (dansyl) and magnetic (free radical) probes has been prepared by a linear multistep protocol from the corresponding monodansylated derivatives. The grafting of the flexible aliphatic radical is realized by the use of a chloromethylnitronyl nitroxide derivative under basic conditions and with KI as a mediator. The synthetic potential of 2-[(5-dimethylamino-1-naphthalenesulfon-amide)methyl]-6-formylpyridine is assessed by the construction, in a first step, of an aliphatic nitroxide radical and subsequently of an additional aromatic radical. The synthetic methods reported herein provide a practical approach to the rational design of ligands bearing various kinds of functionalities such as chromogenic and spin-labeled fragments. A significant merit of this method is that it allows the introduction of the fluorescent substituent onto the pyridine or bipyridine framework at the beginning of the synthetic protocol.