7005. Pamoic Acid

Nomenclature

CAS number: 130-85-8
4,4′-Methylenebis[3-hydroxy-2-naphthalenecarboxylic acid]; 4,4′-methylenebis(3-hydroxy-2-naphthoic acid); 4,4′-methylenedi(3-hydroxy-2-naphthoic acid); 2,2′-dihydroxy-1,1′-dinaphthylmethane-3,3′-dicarboxylic acid; embonic acid.
C23H16O6; mol wt 388.37.
C 71.13%, H 4.15%, O 24.72%.

Description and references

Prepn from 2-hydroxy-3-naphthoic acid + formaldehyde: Strohback, Ber. 34, 4162 (1901); Brass, Sommer, ibid. 61, 993 (1928); Barber, Gaimster, J. Appl. Chem. 2, 565 (1952). Prepn of salts: Puetzer, US 2397903 (1946 to Vick Chem.); Barber, US 2641610 (1953 to May & Baker).

Chemical structure

Properties

Crystals from dil pyridine, dec above 280° without melting. Practically insoluble in water, alcohol, ether, benzene, acetic acid. Sparingly sol in chloroform; sol in nitrobenzene, pyridine.

Derivative

Methyl ether.
C24H18O6; mol wt 402.40.
C 71.63%, H 4.51%, O 23.86%.

Properties

Yellow crystals from dil methanol, dec 277-282°.