Synthesis of Zwitter-Ionic Conjugate of Nido-Carborane with Cholesterol

Abstract

9-HC≡CCH2Me2N-nido-7,8-C2B9H11, a previously described carboranyl terminal alkyne, was used for the copper(I)-catalyzed azide-alkyne cycloaddition with azido-3β-cholesterol to form a novel zwitter-ionic conjugate of nido-carborane with cholesterol, bearing a 1,2,3-triazol fragment. The conjugate of nido-carborane with cholesterol, containing a charge-compensated group in the linker, can be used as a precursor for the preparation of liposomes for BNCT (Boron Neutron Capture Therapy). The solid-state molecular structure of a nido-carborane derivative with the 9-Me2N(CH2)2Me2N-nido-7,8-C2B9H11 terminal dimethylamino group was determined by single-crystal X-ray diffraction.

Synthesis and Antibacterial Activity Studies of the Conjugates of Curcumin with closo-Dodecaborate and Cobalt Bis(Dicarbollide) Boron Clusters

“…Among the methods for obtaining bioconjugates, the Cu(I)-catalyzed 1,3-dipolar [3 + 2] cycloaddition reaction of alkynes to azides is widely used, leading to the formation of 1,2,3 triazoles, termed as the "click"-reaction" [44][45][46]. Earlier, the "click"-reaction was successfully used to obtain a wide range of conjugates of polyhedral boron hydrides with various biologically active molecules, such as nucleosides [47] and chlorine e 6 [48], as well as derivatives of cholesterol based on cobalt/iron bis(dicarbollide) [49][50][51][52], closo-dodecaborate dianion [53] and nido-carborane [54][55][56]. Such reactions must proceed rapidly under ambient conditions, resulting in a high yield of desired 1,2,3-triazole.…”

Synthesis and Reactivity of Cyclic Oxonium Derivatives of nido-Carborane: A Review

“…This approach is widely used for the synthesis of C-substituted derivatives of nido-carborane, as well as derivatives containing substituents at the lower belt of the nido-carborane cage [40]. There are several general methods for the synthesis of B-substituted derivatives with substituents in the upper belt of the nido-carborane cage; however, most of them are used to obtain asymmetrically substituted derivatives [9-X-7,8-C 2 B 9 H 11 ] − [41][42][43][44][45][46][47][48][49].…”