write the reaction for preparation of 1,7-B10H10C2RR'.
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Answer:
The hydrophobic dicarba-closo-dodecaboranes present a group of three isomers with the chemical formula C2B10H12. Depending on the position of the two carbons in the cage, the isomers are designated as closo-1,2 (ortho)-, closo-1,7 (meta)-, and closo-1,12 (para)-carborane. Nucleophilic deboronation of these closo-carboranes produces the corresponding negatively charged, hydrophilic dicarba-nido-undecaboranes 7,8-C2B9H12−, 7,9-C2B9H12−, and 2,9-C2B9H12− (Figure 1).1
Figure 1
Figure 1
Deboronation of closo-1,2-, closo-1,7-, and closo-1,12-dicarba-dodecaboranes to corresponding nido-7,8-, nido-7,9- and nido-2,9-dicarba-undecaboranes, respectively.
Numerous types of carboranyl amines have been described.2–18 In most cases, closo-1,2- or nido-7,8-carborane were used for their synthesis. Many closo-1,2- and nido-7,8-carboranyl amines were synthesized for conjugation with pre-existing biomedical molecules, such as the epidermal growth factor (EGF),19 cyanocobalamin,6 and pyropheophorbide.17 These bioconjugates were prepared for use in Boron Neutron Capture Therapy (BNCT). Similarly, Tolmachev et al. prepared dextran conjugates of nido-7,8-carboranyl propyl amines for tumor imaging studies.20,21. Only very few reports are available describing mcloso-1,7-, nido-7,9-, and closo-1,12-carboranyl amines.14–16