CAS No 520-36-5 , 5,7-dihydroxy-2-(4-hydroxyphenyl)chromen-4-one

Title: Apigenin
CAS Registry Number: 520-36-5
CAS Name: 5,7-Dihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one
Synonyms: 4￠,5,7-trihydroxyflavone; 2-(p-hydroxyphenyl)-5,7-dihydroxychromone; pelargidenon 1449
Molecular Formula: C15H10O5
Molecular Weight: 270.24
Percent Composition: C 66.67%, H 3.73%, O 29.60%
Literature References: The aglucon of apiin and of apigenin-7-glucoside. From apiin by boiling with acids, from apigenin-7-glucoside by enzymatic hydrolysis with emulsin or by boiling with 15% H2SO4. Isoln and structure: Czajkowski et al., Ber. 33, 1992 (1900); Schmid, Waschkau, Monatsh. Chem. 49, 83 (1928); Baker et al., J. Chem. Soc. 1963, 1477. Synthesis: Hutchins, Wheeler, ibid. 1939, 91; Farooq et al., Arch. Pharm. 292, 792 (1959).
Properties: Yellow needles from aqueous pyridine, mp 345-350°. uv max (ethanol): 269, 340 nm (e 18,800; 20,900). Practically insoluble in water; moderately sol in hot alcohol. Sol in dil KOH with intense yellow color.
Melting point: mp 345-350°
Absorption maximum: uv max (ethanol): 269, 340 nm (e 18,800; 20,900)
Use: Has been used to dye Cr mordanted wool yellow. The color is fast to soap.