In order to determine the absolute configuration of urothion (1), the
CD spectra of tri-4-chlorobenzoyl derivatives of 2-amino-6-[(3R)-3,4-d
ihydroxybutyl] pteridin-4(3H)-one and its (3S) compound were compared
with that of the tri-4-chlorobenzoyl derivative obtained from the natu
ral product. R-Configuration was concluded for the secondary hydroxyl
group on the side chain of 1, which is the same configuration as that
of molybdopterin (2). This supports the view that 1 might be a urinary
metabolite of 2.