Studies on urothion. Determination of the absolute configuration of the dephospho form B derived from urothion

In order to determine the absolute configuration of urothion (4), the CD sp ectrum of the dephospho form B (3b) derived from 4 was compared with those of both enantiomers of the dephospho form B ((R)-3b and (S)-3b) which were prepared by asymmetric synthesis. R-Configuration was concluded for the sec ondary hydroxyl group on the side chain of 3b, as well as 4, which is the s ame configuration as that of molybdopterin (1). This supports the view that 4 might be a urinary metabolite of 1.