2,4(1H,3H)-Pyrimidinedione, 1,3-bis[4-[[4-(dimethylamino)-6-methyl-2-pyrimidinyl]thio]butyl]-6-methyl- , compd. with 2,3,5,6-tetrachloro-2,5-cyclohexadiene-1,4-dione (1:1)