Primary Amine Nucleophilic Addition to Nitrilium Closo -Dodecaborate [B 12 H 11 NCCH 3 ] - : A Simple and Effective Route to the New BNCT Drug Design.

In the present work, a convenient and straightforward approach to the preparation of borylated amidines based on the closo -dodecaborate anion [B ₁₂ H ₁₁ NCCH ₃ NHR]-, R=H, Alk, Ar was developed. This method has two stages. A nitrile derivative of the general form [B ₁₂ H ₁₁ NCCH ₃ ] ^- was obtained, using a modified technique, in the first stage. On the second stage the resulting molecular system interacted with primary amines to form the target amidine products. This approach is characterised by a simple chemical apparatus, mild conditions and high yields of the final products. The mechanism of the addition of amine to the nitrile derivative of the closo -dodecaborate anion was studied, using quantum-chemical methods. The interaction between NH ₃ and [B ₁₂ H ₁₁ NCCH ₃ ] ^- ammonia was chosen as an example. It was found that the structure of the transition state determines the stereo-selectivity of the process. A study of the biological properties of borylated amidine sodium salts indicated that the substances had low toxicity and could accumulate in cancer cells in significant amounts.