Phenolphthalein goes clear in acid
Phenolphthalein solution is a synthetic indicator. Indicators are used to find out whether a solution is acidic or basic.
Phenolphthalein is used a s a laxative and also used as a acid -base indicator in titration.
Your best bet is probably mail order. Go to someplace that sells chemistry sets, find the manufacturer's names, look them up online and write to them for a catalog. If you know a friendly...
"C20H14O4"