phenols organobromine compound 2,1-benzoxathiole sultone arenesulfonate ester bromophenol blue 0 3',3'',5',5''-tetrabromophenolsulfonephthalein 3',3'',5',5''-tetrabromophenolsulfophthalein 3H-2,1-Benzoxathiole 1,1-dioxide in which both of the hydrogens at position 3 have been substituted by 3,5-dibromo-4-hydroxyphenyl groups. It is used as a laboratory indicator, changing from yellow below pH 3 to purple at pH 4.6, and as a size marker for monitoring the progress of agarose gel and polyacrylamide gel electrophoresis. It has also been used as an industrial dye. 4,4'-(1,1-dioxido-3H-2,1-benzoxathiole-3,3-diyl)bis(2,6-dibromophenol) 665.698 669.96100 Beilstein:61698 C19H10Br4O5S CAS:115-39-9 CHEBI:59424 InChI=1S/C19H10Br4O5S/c20-12-5-9(6-13(21)17(12)24)19(10-7-14(22)18(25)15(23)8-10)11-3-1-2-4-16(11)29(26,27)28-19/h1-8,24-25H Oc1c(Br)cc(cc1Br)C1(OS(=O)(=O)c2ccccc12)c1cc(Br)c(O)c(Br)c1 UDSAIICHUKSCKT-UHFFFAOYSA-N bromophenol blue, sultone form chebi.owl chebi_ontology obi.owl