Halamek, Emil published the artcileExtraction photometric determination of yperite by phthaleins, Recommanded Product: 3,3-Bis(4-hydroxynaphthalen-1-yl)isobenzofuran-1(3H)-one, the publication is Talanta (1999), 48(1), 163-171, database is CAplus and MEDLINE.
Extraction spectrophotometric determination of sulfidic yperite, based on the reaction with 4 phthaleins, was developed. The method is tech. simpler than determining yperites with reagent T-135 (alk.-aqueous ethanolic thymol phthalein solution) because it does not require heating at 80°, cooling, and acidifying the reaction mixture Selecting the appropriate phthalein, especially optimizing the reagent composition and extracting the colored reaction product in chloroform, markedly increased the selectivity of the determination of yperites (HD, HN-3). The reaction is performed in a medium of increased polarity due to the low alc. content which enables the reaction to proceed at 5-20° without any marked loss of sensitivity. Using 1H and 13C NMR spectroscopy, the reaction products of HD and o-cresol phthalein were identified and an ionic mechanism for the reaction of HD with phthaleins is suggested.
Talanta published new progress about 596-01-0. 596-01-0 belongs to benzofurans, auxiliary class Benzofuran,Naphthalene,Alcohol,Ester, name is 3,3-Bis(4-hydroxynaphthalen-1-yl)isobenzofuran-1(3H)-one, and the molecular formula is C28H18O4, Recommanded Product: 3,3-Bis(4-hydroxynaphthalen-1-yl)isobenzofuran-1(3H)-one.
Referemce:
https://en.wikipedia.org/wiki/Benzofuran,
Benzofuran | C8H6O – PubChem