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PIPERINE, C17H19NO3

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Originally appearing in Volume V21, Page 635 of the 1911 Encyclopedia Britannica.
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PIPERINE, C17H19NO3 , an See also:alkaloid found in the fruits of See also:Piper nigrum and P. longum. It forms See also:white prisms, which melt at 128°-219°. It is almost insoluble in See also:water, but readily soluble in See also:alcohol and See also:ether. It is a very weak See also:base, salts being only formed with See also:mineral acids, and these are dissociated by water. Alcoholic potash decomposes it into piperidine, C5H11N, and piperic See also:acid, C,2H,0O4. The constitution of piperic acid was elucidated by R. See also:Fittig and his pupils (See also:Ann., vols. 152, 159, 168, 216, 227) and shown to be (I). Piperine consequently is (2). - - /o-(\ CH/ O—\`--CH : CH .CH : CH•COOH O—\/ CH:CH•CH:CH•CO•N(See also:CH2)5 (2) Oxidation with See also:potassium permanganate converts piperic acid into See also:piperonal, C8H603, and piperonylic acid, C8H604. The latter when heated with hydrochloric acid to 170°, or water to 200°, separates See also:carbon with the formation of protocatechuic acid, I.2-dioxy-3-benzoic acid, C6H3(OH)20OOH. Conversely, by See also:heating protocatechuic acid with potash and methylene iodide, piperonylic acid was regained.

These results show that piperonylic acid is the methylene ether of protocatechuic acid. Piperonal (q.v.) is the corresponding aldehyde. Piperic acid differs from piperonylic acid by the See also:

group C4H4, and it was apparent that these carbon atoms must be attached to the carbon See also:atom which appears in the carboxyl group of piperonylic acid, for if they were directly attached to the See also:benzene See also:ring polycarhoxylic acids would result in oxidation. The above See also:formula for piperic acid was See also:con-firmed by its See also:synthesis by A. Ladenburg and M. Scholtz (Ber., 1894, 27, p. 2958) from piperonyl acrolein (the condensation product of piperonal and acetaldehyde) and acetic acid. The synthesis of piperine follows from the interaction of piperyl chloride (formed from piperic acid and See also:phosphorus pentachloride) and piperidine (L. Riigheimer, Ber., 1882, 15, p.

End of Article: PIPERINE, C17H19NO3

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