Synthesis of 1-amino-3-{2-[7-(6-deoxy-α/β-D-galactopyranos-6-YL) -1,7-dicarba-closo-dodecaboran(12)-1-YL]ethyl}cyclobutanecarboxylic acid hydrochloride

1-Amino-3-{2-[7-(6-deoxy-α/β-D-galactopyranos- 6-yl)-1,7-dicarba-closo-dodecaboran(12)-1-yl]ethyl}cyclobutanecarboxylic acid was synthesized as a potential new agent for boron neutron capture therapy. The key step in the synthesis is the alkylation of 3-{2-[1,7-dicarba-closo-dodecaboran(12)-1-yl]ethyl}cyclobutanone ethylene monothioketal with 1,2:3,4-di-O-isopropylidene-6-O-triflyl-α-D-galactopyranose which gave the precursor ketone that was then converted to the title amino acid via a Bücherer-Strecker synthesis followed by removal of isopropylidene groups in HCl. Preliminary toxicity data in A 435 cancer cells were obtained.