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

Abstract

Cu- and Pd-catalyzed arylation of aminocholanes has been described for the first time. While this Cu-catalyzed protocol provides high yields in reactions of aminocholanes with iodoarenes, Pd catalysis was found to be preferable for the reactions of aminocholanes with dichloroanthraquinones. UV–vis titration of bis(cholanylamino)anthraquinones with a series of cations demonstrated their high binding affinity to Cu2+, Al3+, and Cr3+.

Domino Construction of Benzoxazole-Derived Sulfonamides via Metal-Free Denitrogenation of 5-Iodo-1,2,3-triazoles in the Presence of SO2 and Amines

“…To evaluate the applicability of the developed protocol toward derivatization of natural compounds, we have prepared steroid-anchored sulfonamide 3ak (Scheme ). The starting amine was readily synthesized from deoxycholic acid via sequential amidation and reduction . The reaction of 1a with steroidal amine was performed under standard conditions and afforded 3ak as an equimolar mixture of epimers, albeit in a moderate yield, in accordance with the previously mentioned detrimental effect of hydroxyl groups.…”

“…Prepared from iodotriazole 1a (68.6 mg, 0.20 mmol), DABSO (96.2 mg, 0.40 mmol), and (3α,5β,12α)-24-aminocholane-3,12-diol (151.0 mg, 0.40 mmol) according to the general procedure; eluent: hexanes–EtOAc = 1:2. Equimolar mixture of epimers.…”

A Route to Triazole-Fused Sultams via Metal-Free Base-Mediated Cyclization of Sulfonamide-Tethered 5-Iodotriazoles

“…To demonstrate the utility of the developed protocol in derivatization of polyfunctional natural compounds, we have prepared azidobenzene­sulfonamide 3n from deoxycholic acid which is an important member of the bile acid group (Scheme ). Azide 3n was converted to the corresponding iodotriazole 1y , which smoothly underwent a cyclization under the standard conditions, furnishing triazole-fused sultam 2y bearing a steroidal moiety in almost quantitative yield (99%).…”

“…Prepared from 5 (261.1 mg, 1.2 mmol) and (3α,5β,12α)-24-aminocholane-3,12-diol (542.3 mg, 1.44 mmol) according to the general procedure; eluent: CH 2 Cl 2 –MeOH = 15:1. Yield 592 mg (88%).…”

Recent achievements in copper catalysis for C–N bond formation

“…24-Amino derivatives of the cholanols were shown to participate in the Cu(I)-catalyzed amination: the reaction with p-iodotoluene catalyzed with CuI/L1 using K2CO3 as a base and run in DMSO at 110 o C provided almost quantitative yield of the desired product (Scheme 21), and the reactions with 1,3-diiodobenzene or 4,4'-diiodobiphenyl afforded bissteroid derivatives in quite reasonable yields [68]. This reaction is a rare example of the diamination of dihaloarenes in the presence of copper catalyst.…”