2,2'-Dithiodimethylenedipyridine 1,1'-dioxide 46910-44-5 BRN 1433666 Bis(2-pyridylmethyl)disulphide N,N'-dioxide Pyridine, 2,2'-(dithiobis(methylene))bis-, 1,1'-dioxide Pyridine, 2,2'-dithiodimethylenedi-, 1,1'-dioxide