227457-59-2

Upstream product

• 227457-56-9 3-(4-Bromobenzyloxy)-2,6-bis(hydroxymethyl)pyridine 
• 109-00-2 3-HYDROXYPYRIDINE 
• 227457-57-0 3-(4-Bromobenzyloxy)-2,6-bis(chloromethyl)pyridine 
• 227457-58-1 12-(4-Bromobenzyloxy)-3,6,9-tris(2-nitrobenzenesulfonyl)-3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1⁽¹⁵⁾,11,13-triene 
• 38029-16-2 2,6-bis-(hydroxymethyl)-3-hydroxypyridine 
• 589-15-1 1-bromomethyl-4-bromobenzene 

Relevant academic research and scientific papers

Diethoxyphosphoryl as a protecting-activating group in the synthesis of polyazacyclophanes

The fully diethoxyphosphoryl(Dep)-protected polyamines 1b-3b were prepared from the corresponding polyamines with 'diethyl phosphite' (= diethyl phosphonate) and CCl4 in a solid base/organic liquid two-phase system in the presence of Bu4NBr as phase-transfer catalyst. Subsequent phase-transfer-catalyzed alkylation of phosphoramidates 1b-3b with bis(chloromethyl)arenes 5-8 in the presence of Bu4N(HSO4) followed by deprotection gave good yields of polyazacyclophanes 9a-16a.

Contrast agents for magnetic resonance imaging: A novel route to enhanced relaxivities based on the interaction of a Gd(III) chelate with poly-β-cyclodextrins

This study proposes a novel route to improved contrast agents for magnetic resonance imaging (MRI) applications based on the formation of a non-covalent adduct between a paramagnetic complex and an exogeneous macromolecule. For this purpose a 12-membered pyridine-containing triacerate macrocyclic ligand with a p-bromobenzyloxy substituent on the pyridine moiety was synthesized. The Gd(III) complex containing this ligand shows a relaxivity of 8.25mM-1S-1 at 20MHz and 25°C. The hydrophobic p-bromo- benzyloxy moiety promotes the interaction of the chelate with human serum albumin (HSA) (K(a) x 102M-1) and with β-cyclodextrin (K(a) = 8 x 102M- 1). Upon replacing β-cyclodextrin with a poly-β-cyclodextrin substrate (MW = ca. 6000 Da) a further relaxation enhancement is detected as a consequence of the increased molecular size of the resulting inclusion compound. In a typical experiment in blood serum, the observed relaxivity is 32mM-1S-1 (20 MHz, 25°C) when the concentrations are as follows: Gd(III) chelate I mM, poly-β-cyclodextrin 10mM, HSA 0.58mm. Under these conditions the Gd(III) chelate is mainly present as an inclusion compound with the poly-β-CD. This finding suggests a potential use for such a Gd(III) chelate/poly-β-CD system in MR angiographic applications. This study proposes a novel route to improved contrast agents for magnetic resonance imaging (MRI) applications based on the formation of a non-covalent adduct between a paramagnetic complex and an exogeneous macromolecule. For this purpose a 12-membered pyridine-containing triacetate macrocyclic ligand with a p-bromo-benzyloxy substituent on the pyridine moiety was synthesized. The GdIII complex containing this ligand shows a relaxivity of 8.25 mM-1 s-1 at 20 MHz and 25 °C. The hydrophobic p-bromo-benzyloxy moiety promotes the interaction of the chelate with human serum albumin (HSA) (Ka = 4×102 M-1) and with β-cyclodextrin (Ka = 8×102 M-1). Upon replacing β-cyclodextrin with a poly-β-cyclodextrin substrate (MW = ca. 6000 Da) a further relaxation enhancement is detected as a consequence of the increased molecular size of the resulting inclusion compound. In a typical experiment in blood serum, the observed relaxivity is 32 mM-1 s-1 (20 MHz, 25 °C) when the concentrations are as follows: GdIII chelate 1 mM, poly-β-cyclodextrin 10 mM, HSA 0.58 mM. Under these conditions the GdIII chelate is mainly present as an inclusion compound with the poly-β-CD. This finding suggests a potential use for such a GdIII chelate/poly-β-CD system in MR angiographic applications.