B 1620 (OTTO) 4-Benzyloxybenzaldehyde, 97% Cas 4397-53-9 - used in the synthesis of (5-fluoro-(2R*,3S*)-2,3-bis(4-hydroxyphenyl)pentanenitrile), an estrogen receptor β-selective ligand. It is a position isomer of the adenylyl cyclase activator 2-benzyloxybenzaldehyde.