4,5-Furoxanobenzofuroxan 4-27-00-09648 (Beilstein Handbook Reference) 5714-12-5 BRN 0025923 Benzo(1,2-c:3,4-c')bis(1,2,5)oxadiazole, 3,8-dioxide FBF Furoxanobenzofuroxan NSC 228139