CuAAC Synthesis and Anion Binding Properties of Bile Acid Derived Tripodal Ligands

Abstract

The copper‐catalyzed azide–alkyne cycloaddition reaction was used for the preparation of a series of bis‐ and tris‐3‐ and 24‐5β‐cholanetriazolyl derivatives of phosphorus acids, which contained anion‐binding triazolium sites and hydrophobic cholane residues. The influence of the location of the triazolium moiety (in 3α‐, 3β‐position) on fluoride‐ion complexation was investigated. The anion‐binding properties of tris(triazolium) ligands were studied for a series of inorganic and organic anions and high complexation constants were observed with fluoride, hydrosulfate, and benzoate anions.

Synthesis of New Cisplatin Derivatives from Bile Acids

“…The methylation of the carboxylic group with methanol/HCl was followed by LiAlH 4 reduction of methyl ester 9 to primary alcohol 10. Then the hydroxyl group at C-24 was converted into methanesulfonate 11, which was further transformed into azide 12 with sodium azide in DMF [33]. Deprotection of the hydroxyl group at C-3 allowed to obtain 13 in a good overall yield (all steps were fairly efficient).…”

“…Bile acids were purchased from TCI EUROPE N.V. Compound 13 was synthesized according to literature procedure [33] starting from lithocholic acid (7a) in 77% total yield.…”

Copper-catalyzed steroid reactions

“…In an alternative approach to 24-alcohol 174, the 3,12-diacetoxy-5-cholan-24-oic acid 173 67 upon treatment with chloroformate ethyl ester-triethylamine mixture was transformed to the mixed anhydride, which could be reduced with sodium borohydride to the alcohol 174 in 82% yield. The 3,12-diacetoxy-5-cholan-24-yl The copper-catalyzed azide-alkyne cycloaddition reaction was used in 2015 by Lukashev and co-workers 69 for the preparation of a series of bis-and tris-3-and 24-5β-cholanetriazolyl derivatives of phosphorus acids, which contained anion-binding triazolium sites and hydrophobic cholane residues. Bile azides 181a-c and 182 were synthesized by using a standard route by nucleophilic substitution of the corresponding α-and β-mesylates with sodium azide in dimethyl sulfoxide (DMSO; Scheme 46).…”

Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands

“…Consequently, the idea of molecular pockets or jellyfish resembling receptors with open “architecture” (Fig. 1), which contain two or more bile acid fragments, has attracted more attention in recent years [9–16]. …”

“…Later, two modern synthetic approaches based on metal-catalyzed reactions were applied for the modification of bile acids – cross-coupling [28–29] (Scheme 1) and Cu(I)-catalyzed cycloaddition of azides to alkynes (Fig. 1) [11,16,30–32]. …”