2-Hydroxy-1-(2-hydroxy-4-sulfo-1-napthylazo)-3-naphthoicacid 2-Naphthalenecarboxylic acid, 3-hydroxy-4-[(2-hydroxy-4-sulfo-1-naphthalenyl)azo]- 2-Naphthoic acid, 3-hydroxy-4-[(2-hydroxy-4-sulfo-1-naphthyl)azo]- 3737-95-9 Calcon 3-carboxylic acid Calconcarbonic acid Calconcarboxylic acid NN NSC97307 Patton and Reeder's indicator Patton-Reeder indicator