1-Naphthalenesulfonic acid, 6-diazo-5,6-dihydro-5-oxo-, ester with 2,2'-thiobis(1-naphthalenol) 118276-85-0 Condensation products of 2,2'-dihydroxy-1,1'-dinaphthylsulfide and 2-diazo-1-naphthol-5-sulfonyl chloride