Synthesis of boronated phenylalanine analogues with a quaternary center for boron neutron capture therapy

Abstract

2-Amino-2-methyl-3-(4-dihydroxyborylphenyl)propionic acid (3, α-methyl-BPA) and 1-amino-3-(4-dihydroxyborylbenzyl)cyclobutanecarboxylic acid 4, which are (4-dihydroxyborylphenyl)alanine (BPA) analogues containing a quaternary center, have been synthesized from 4-allylbromobenzene. α-Methyl-BPA has also been prepared from D,L-alanine, and the route is suitable for the synthesis of α-alkyl-BPA. Both 3 and 4 exhibit very similar Rf values indicating similar lipophilicities. The products have been prepared as potential boron carriers for Boron Neutron Capture Therapy.