Folic Acid

A water-soluble, photolabile vitamin consisting of pteroic acid linked
to glutamic acid. (Pteroic acid = 2-amino-4-hydroxy-6-methylpteridine
linked at the 6-position to the amino group of p-aminobenzoic acid.)
polyglutamate forms of folic acid also occur (e.g. pteroyltriglutamic acid);
certain of these may be specifically required for certain reactions. (Ref.
*)

Physical data (Ref. **)

Extremely this platelet (elongated at two ends) from hot water, no
mp. Darkens and chars from about 250 degrees C. Very slightly
soluble in cold water (0.0016 mg/mL at 25 degrees C), soluble to about
1% in boiling water. Slightly soluble in methanol, appreciably less
soluble in ethanol and butanol. Insoluble in acetone, chloroform,
ether, benzene. Relatively soluble in acetic acid, phenol, pyridine,
solutions of alkali hydroxides and carbonates. Soluble in hot dil
HCl and H2SO4. Injectable
solutions are prepared by dissolving folic acid in normal sodium bicarbonate
solution (which should be sterilized by filtration) or by preparing solution
of the sodium or methylglucamine salt. A suspension of 1 g folic
acid in 10 mL water has a pH of 4.0-4.8. Aq solution prepared with
sodium bicarbonate have a pH between 6.5 and 6.8.

Ref. *: Dictionary of Microbiology, Singleton and Sainsbury (John Wiley
& Sons)

Ref. **: The Merck Index 12th Edition