Design and Synthesis of Two Aromatic Amines with Dendritic Structure

The design and synthesis of two aromatic amines with dendritic structures, i.e . 3,4,5‐tribenzyloxyaniline (3,4,5‐G 1 ‐NH 2 ) and 2,5‐dibenzyloxyaniline (2,5‐G 1 ‐NH 2 ), were conducted. A coupling reaction of three or two equivalents of benzyl bromide to one equivalent of methyl hydroxybenzoate generated methyl 3,4,5‐tribenzyloxybenzoate (3,4,5‐G 1 ‐COOCH 3 ), methyl 2,5‐dibenzyloxybenzoate (2,5‐G 1 ‐COOCH 3 ) and 2,6‐dibenzyloxybenzoate (2,6‐G 1 ‐COOCH 3 ) in high yields. All G 1 ‐COOCH 3 derivatives were studied by X‐ray analysis. The results show that these dendrons have sufficient volume to be used as the fine ligands for certain catalysts. The amide intermediates (benzamide, G 1 ‐CONH 2 ) were obtained by reaction between ammonia and G 1 ‐COOCH 3 . Interestingly, 2,6‐dibenzyloxybenzamide (2,6‐G 1 ‐CONH 2 ) can not be prepared in the same condition, which may be due to the overlarge steric block. Sodium hypochlorite was an effective oxidant to generate methyl carbamates G 1 ‐ NHCO 2 CH 3 .