Unsaturated compounds containing nitrogen. Part 5. Reactions of 1,4-dichloro-1,4-diphenyl-2,3-diazabutadiene with nucleophiles

1,4-Dichloro-1,4-diphenyl-2,3-diazabutadiene (1) reacts with potassium cyanate to give 5-phenyl-1,2,4-triazol-3(2H)-one (9), but with potassium thiocyanate it gives the 1-chloro-4-thiocyanato-2,3-diazabutadiene (3). The thiocyanate (3) is not isomerized by heat, but is hydrolysed by acid to a mixture of 2,5-diphenyl-1,3,4-oxadiazole and 2-amino-5-phenyl-1,3,4-thiadiazole. Sodium hydrosulphide, potassium ethylxanthate, and thiourea all convert the dichlorodiazabutadiene (1) into 2,5-dipheyl-1,3,4-thiadiazole, while 2-aminobenzenethiol converts it into 2-phenylbenzothiazole.