Title: Purpurogallin
CAS Registry Number: 569-77-7
CAS Name: 2,3,4,6-Tetrahydroxy-5H-benzocyclohepten-5-one
Molecular Formula: C11H8O5
Molecular Weight: 220.18
Percent Composition: C 60.00%, H 3.66%, O 36.33%
Literature References: The aglycone of several glycosides from various nutgalls. Prepn by oxidation of pyrogallol: Perkin, Steven, J. Chem. Soc. 83, 192 (1903); Perkin, ibid. 101, 803 (1912); Nierenstein, Spiers, Ber. 46, 3151 (1913); Evans, Dehn, J. Am. Chem. Soc. 52, 3647 (1930). Structure: Willstätter, Heiss, Ann. 433, 17 (1923); Barltrop, Nicholson, J. Chem. Soc. 1948, 116. Synthesis: Caunt et al., ibid. 1950, 1631; 1951, 1313.
Properties: Deep red needles from glacial acetic acid, dec 274-275°. Sparingly sol in most solvents.
Derivative Type: Diglucoside
Additional Names: Dryophantin
Molecular Formula: C23H28O15
Molecular Weight: 544.46
Percent Composition: C 50.74%, H 5.18%, O 44.08%
Properties: Coloring matter of "red pea" gall produced by Dryophanta divisa Ald. on Quercus pedunculata Ehrh., Fagaceae: Nierenstein, J. Chem. Soc. 115, 1328 (1919); Nierenstein, Swanton, Biochem. J. 38, 373 (1944). Dark red needles with bronze luster, mp 220-221°. Slightly sol in water, cold alcohol; sol in boiling alcohol; in methanol, acetone.
Melting point: mp 220-221°
Use: As an additive to edible or inedible fats or oils, hydrocarbon fuels or lubricants, retards oxidation or metal contamination: Thompson, US 2770545 (1956 to Universal Oil Prod.). |