THE MERCK INDEX on CD-ROM / Version 12:3 / 1999 =============================================== Monograph number: 7630. Title: Piperonylic Acid. CAS Registry number: [94-53-1] CAS name(s): 1,3-Benzodioxole-5-carboxylic acid; Additional name(s): 3,4-methylenedioxybenzoic acid; protocatechuic acid methylene ether. Molecular formula: C8H6O4 ; Molecular weight: 166.13. Percent Composition: C 57.84%, H 3.64%, O 38.52%. Literature references: Occurs in Paracoto bark. Prepd by permanganate oxidation of piperonal: Shriner, Kleiderer, Org. Syn. 10, 82 (1930). Properties: Prisms (by sublimation), needles from alc, feathery crys tals from water. mp 229° . Sublimes around 210°. Slightly sol in water, chloroform, cold alcohol, ether. Absorption spectrum: Dobbie, Lauder, J. Chem. Soc. 83, 621 (1903) Melting Point: 229° Derivative: Methyl ester, Molecular Formula: C9H8O4 , Properties: mp 53° . Sublimes easily. Volatile in steam. Freely sol in alcohol, ether Melting Point: 53°