2-Methyl-1-phenyl-1,2-dihydro-3,6-pyridazinedione (II) reacted with Lawesso
n's reagent (I) in different molar ratio, to give the dithione V and the mo
nothiones VI and VII. 1-Phenyl-1,2-dihydro-3,6-pyridazinedione (III) reacte
d with reagents Ia-e to give the disulphide VIII, the dithione IX and 1,3,2
-oxathiophosphole derivative XII. 2-Phenyl-2,3-dihydro-1,4-phthalazinedione
(IV) reacted with reagents Ia-e to give the dithione XIV and monothione XV
.