Absolute configuration of urothion, a pigment of urine: Asymmetric synthesis of 2-amino-6-(3,4-dihydroxybutyl)pteridin-4(3H)-one, the desulfurization product
In order to determine the absolute configuration of urothion, 2-amino-6-[(3R)-3,4-dihydroxybutyl]-pteridin-4(3H)-one and its (3S) compound were synthesized. Comparing the CD spectra of their tri-4-chlorobenzoates with that derived from the natural product, R-configuration was concluded for the secondary hydroxyl group on the side chain of urothion.