5(6)-Aminofluorescein

The Uses of 5(6)-Aminofluorescein

Fluoresceinamine is a fluorescent labeling precursor used to prepare FITC.

Purification Methods

Dissolve it in EtOH, treat with charcoal, filter, evaporate and dry the residue in a vacuum at 100o overnight. Also recrystallise it from 6% HCl, then dissolve it in 0.5% aqueous NaOH and precipitate it by acidifying with acetic acid. The separate amines are made from the respective nitro compounds, which are best separated via their acetate salts. They have similar RF of 0.26 on Silica Gel Merck F254 in 5 mL MeOH + 150 mL Et2O saturated with H2O. IR (Me2SO) has a band at max 1690 cm-1 (CO2-) and sometimes a weak band at 1750 cm-1 due to the lactone. UV (EtOH) of the 6-max isomer has max at 222nm ( 60 000) and the 5-isomer at max 222nm ( 60 000) and 285nm ( 20.600). [IR: McKinney & Churchill J Chem Soc (C) 654 1970, McKinney et al. J Org Chem 27 3986 1962, UV: Verbiscar J Org Chem 29 490 1964, Beilstein 19 III/IV 4337, 19/8 V 713.]