2-Hydroxyethoxy-closo-undecahydrododecaborate(12)([B12H11CH2CH2OH]2−) as a new prospective reagent for the preparation of closo-dodecaborate building blocks and thymidine and 2-deoxyuridine conjugates linked via short spacer

Abstract

Reaction of dioxonium derivative of closo-dodecaborate ([B12H11O+(CH2)4O]−) with an access of NaCN in boiling EtOH led to [B12H11OCH2CH2OH]2− with an excellent yield as a result of ring cleavage followed by elimination of acrylonitrile. The same entry in aprotic DMFA afforded regular ring cleavage product [B12H11OCH2CH2OCH2CH2CN]2. Subsequent work up of this nitrile with sodium methanolate in MeOH led to the alcohol ([B12H11OCH2CH2OH]2−) as well. The above alcohol was converted into new functionalized derivatives [B12H11OCH2CH2OMs]2− and [B12H11OCH2CH2N3]2− respectively using straightforward organic reactions. These new building blocks were employed for the preparation of novel closo-dodecaborate pyrimidine nucleoside conjugates.