3022. 4′,5′-Dibromofluorescein

Nomenclature

CAS number: 596-03-2
4′,5′-Dibromo-3′,6′-dihydroxyspiro[isobenzofuran-1(3H),9′-[9H]xanthen]-3-one; 4,5-dibromo-3,6-fluorandiol; D & C Orange No. 5; C.I. Solvent Red 72; C.I. 45370:1.
C20H10Br2O5; mol wt 490.10.
C 49.01%, H 2.06%, Br 32.61%, O 16.32%.

Description and references

Prepn from fluorescein, q.v.: A. Baeyer, Ann. 183, 1 (1876); M. A. Phillips, J. Chem. Soc. 1932, 724. Metabolism: J. M. Webb et al., J. Pharmacol. Exp. Ther. 137, 141 (1962). See also: Colour Index vol. 4 (3rd ed., 1971) p 4425.

Chemical structure

Properties

Red plates, mp 285°. Slightly sol in water (orange with faint yellow fluorescence); sol in ethanol (orange with greenish-yellow fluorescence) and in acetone (pink with yellow fluorescence). Red-yellow soln in conc H2SO4, turning yellow-brown with orange ppt on dilution. Absorption spectra: R. C. Gibbs, C. V. Shapiro, J. Am. Chem. Soc. 51, 1769 (1929).

Derivative

Disodium salt.

Nomenclature

C.I. Acid Orange 11.
C20H8Br2Na2O5; mol wt 534.06.
C 44.98%, H 1.51%, Br 29.92%, Na 8.61%, O 14.98%.

Use

D & C Orange No. 5 permitted for use in lipsticks, mouthwashes and dentifrices: Fed. Regist. 47, 49632 (1982).