# Synthesis, Molecular Docking and Biological Evaluation of A-Ring-Carborane-Vitamin D Analogues

## TL;DR

Researchers created new vitamin D analogues with modified A-rings using carborane units and tested their biological effects.

## Contribution

The paper introduces new vitamin D analogues with A-ring carborane modifications and evaluates their biological activity.

## Key findings

- The new analogues function as VDR agonists with antiproliferative activity similar to 1,25D3.
- Compound 4 induced strong CYP24A1 mRNA activation, unlike compound 5 and similar to 1,25D3.
- Both analogues caused hypercalcemic effects in mice similar to 1,25D3.

## Abstract

The active form of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25D3), regulates a number of physiological and pathological processes, including cell proliferation and differentiation. Thousands of analogues of 1,25D3 have been developed with the aim of selective effects for medical use. Here we describe the synthesis of two new unconventional vitamin D analogues bearing A-ring modifications with ortho-carborane (dicarba-o-closo-1,2-dodecaborane) units. The ligands function as agonists for VDR with similar antiproliferative activities as 1,25D3. Whereas mice treated with the analogues 4 and 5 exhibited similar hypercalcemic activities as 1,25D3, only compound 4 and 1,25D3 induced the strong activation of CYP24A1 mRNA expression but not compound 5.