1g piperine and 10mL 10% alcoholic potassium hydroxide are refluxed for 90min.
\nthe ethanolic solution is evaporated to dryness under reduced pressure, the receiver
\nbeing cooled in an ice-salt bath. the solid potassium piperinate is suspended in hot
\nwater and acidified with hydrochloric acid. the voluminous yellow percipitate is collected
\non a buchner funnel, washed with cold water, and recrystalized from ethanol to yield
\npiperic acid as yellow needels of mp 216-217\u00b0C. the strongly basic ethanolic distillate
\nin the receiver is saturated with hydrochloric acid and evaporated to dryness to give
\npiperidine hydrochloride, which melts at 244\u00b0C after recrystallization from ethanol.<\/p>\n
[06, page 236-238]<\/p>\n
the cleavage of piperine was accomplished with alcoholic KOH … . numerous
\nexperiments showed us that the following procedure is the most practical and
\ngives almost the theoretical yield. in a roomy flask connected with an ascending
\ncooler a mixture of 1 part fine grinded piperine with 1 part KOH and 5 parts
\nusual alcohol is boiled mildly about 24h in a water-bath.
\n…
\nin our experiments the decomposition was finished largely after 24h heating. after
\ncooling the precipitation consisting of yellowish glossing leaflets was separated
\nthrough a cheesecloth from the dark piperidine containing mother liquor, washed
\nout with cold alcohol and recrystallized a few times from hot water under addition
\nof animal coal. so the piperic acid potassium salt is obtained very easily pure in
\ncompletely colorless, warty grouped prisms, that become again yellow colored at
\nlight. – the filtered acoholic mother liquor gives, if boiled 24h anew with one third of
\nthe prior applied KOH amount, another small amount of very impure, dark colored
\npiperic acid potassium salt.
\n…
\nto obtail the free acid, the potassium salt was dissolved in about 50 parts boiling
\nwater, a small excess of hydrochloric acid was brought into the solution and the
\nwhole was heated for some time. the piperic acid was obtained as a lightish
\nsulphur-yellow, amorphous, looser precipitation. … after the washing and drying
\nthe acid was recrystallized from boiling alcohol. for the dissolution of 1 part piperic
\nacid about 50 parts alcohol were required.<\/p>\n
[18, page 27-29]<\/p>\n
… place 1g of piperine and 10mL of a 10% solution of KOH in 95% ethanol in
\na 50mL round-bottomed flask. attach a condenser and heat at reflux for 90min.
\nattach the flask to an apparatus suitable for distillation under reduced pressure.
\nusing an aspirator distill until dryness (1) and collect the distillate in an ice cooled
\nreceiver flask. scrape the residue into a 125mL erlenmeyer flask (use water to rinse
\nmaterial clinging to the sides of the round-bottomed flask). suspend the residue
\nin a total volume of about 50mL of water, heat over a steam bath, and then acidify
\n(in the hood) with hydrochloric acid. occasionally swirl the erlenmeyer flask.
\ncollect the voluminous yellow precipitate of piperic acid by suction filtration, wash
\nwith cold water, and recrystallize from hot ethanol (2).
\nnote the odor of the distillate. check the distillate with litmus or pH paper (3).<\/p>\n
(1) bumping may occur at this step.<\/p>\n
(2) the yield of crude piperic acid is high. the melting point of the recrystallized acid
\nis 214-215\u00b0.<\/p>\n
(3) the hydrochloride salt of piperidine may be isolated …; however we have found
\nthis to be difficult and probably not worth the effort.<\/p>\n
[01, page 528]<\/p>\n
piperine (28.0g, 98mmol, mp 132\u00b0C) dissolved in 200mL ethylene glycol
\nand refluxed at 180\u00b0C after adding 25g potassium hydroxide and after
\nthe completion of the reaction the contents diluted with sufficient
\namount of water and acidified with 2N HCl. the resulting precipitate
\nfiltered and dried to give crude product which on crystallisation from
\nethanol gave piperic acid (13.8g, 65%, mp 217\u00b0C) as pale yellow solid
\n(lit. mp 217\u00b0C).(27)<\/p>\n
(27) dictionary of natural products 1994 4 3920; chapman, hall<\/p>\n
[03]<\/p>\n
to piperine (2g, 0.7mmol, 1eq), 20% of methanolic KOH (100mL) was added and
\nrefluxed for 2days. after completition of the hydrolysis, methanol was removed
\nunder reduced pressure and a yellow coloured oily solid was obtained. this
\nresidue was dissolved in 50mL water and acidified with 6N HCl to pH a yellowish percipitate of piperinic acid. recrystallization from methanol
\ngave yellow needles (0.9g, 60% yield)). mp 206\u00b0-208\u00b0C (lit mp 217\u00b0-218\u00b0 (1))<\/p>\n
(1)
\ntetrahedron 1967 23: 1769-1781
\n\u00abalkaloids of piper longum linn-I structure and synthesis
\nof piperlongumine and piperlonguminine\u00bb
\na.chatterjee, c.p.dutta<\/p>\n
[02, page 69(60), 76(67)]<\/p>\n
in a 1L round-bottom fask was placed 6g piperine, 500mL ethanol and 100mL
\naqueous LiOH 90g\/L solution. the resultant solution was refuxed for 140h, and
\nthe reaction was then quenched by addition of 35mL concentrated hydrochloric
\nacid. the solid formed was removed by filtration and recrystalized from THF to
\nproduce piperic acid in 85% yield, mp 126-127\u00b0C.<\/p>\n
[09]<\/p>\n
(mp 126-127\u00b0C looks like an error. it seems that 1 and 2 are permuted.
\nother papers report mp 216-217\u00b0C. also 140h sounds extremely long [3base])<\/p>\n
degradation of piperine to piperic acid with KOH in MeOH\/H2O<\/a> (german)<\/p>\n hydrolysis of piperine to piperic acid [26, (2)]<\/p>\n hydrolize with NaOH in alcohol. (MeOH\/EtOH both verified) [27]<\/p>\n hydrolysis of piperine to piperic acid and piperidine [28]<\/p>\n piperine … alkaline hydrolysis … 2N KOH in diethylene glycol and reflux 2h [29]<\/p>\n the present invention relates to a preparation technology [01] [02] [03] [06] [09] [18] [26] [27]
\nof piperic acid … which uses pepper or piper longum … [34]<\/p>\nReferences<\/h2>\n
\n\u00ablaboratory experiments in organic chemistry\u00bb<\/strong> 3.edition 1979
\njerry r. mohrig, douglas c. neckers
\nd. van nostrand company, new york
\nISBN 0-442-25471-7<\/p>\n
\npatent GB2370989, 2002-07-17
\n\u00abpiperine analogues for the treatment of skin conditions\u00bb<\/strong>
\nVENKATASAMY RADHAKRISHNAN, RAMAN AMALA, HIDER ROBERT CHARLES
\nBTG INT LTD
\npage 69(60)<\/a><\/p>\n
\nbioorganic & medicinal chemistry 2000 8(1): 251-268<\/a>
\n\u00abstructure\u0096activity relationship of piperine and its synthetic
\nanalogues for their inhibitory potentials of rat hepatic microsomal
\nconstitutive and inducible cytochrome P450 activities\u00bb<\/strong>
\nSurrindera Koul, Jawahir L.a Koul, Subhash C.a Taneja, Kanaya L.a Dhar,
\nDeshvir S.b Jamwal, Kuldeepb Singh, Rashmeet K.b Reen, Jaswantb Singh<\/p>\n
\n\u00abnatural products – a laboratory guide\u00bb <\/strong>2.edition 1991
\nraphael ikan; academic press, inc; ISBN 0-12-370551-7<\/p>\n
\npest management science 2000 56(2): 168-174<\/a>
\n\u00absynthesis and insecticidal activity of new amide derivatives of piperine\u00bb<\/strong>
\nvanderl\u00facia fde paula, luiz c de a barbosa, ant\u00f4nio j demuner,
\ndorila pil\u00f3-veloso, marcelo c pican\u00e7o
\nabstract<\/strong>:<\/strong> the natural lipophilic amides piperine and piperiline were isolated
\nfrom piper nigrum l (piperaceae). piperine was hydrolysed into piperic acid
\n(85% yield) which was converted into 16 amides (28-89% yield). the contact
\ntoxicity of all synthetic amides, and also that of piperine and piperiline, at the
\ndose 10 \u00b5g per insect, was evaluated for the brazilian economically important
\ninsects ascia monuste orseis latr, acanthoscelides obtectus say, brevicoryne
\nbrassicae l, protopolybia exigua de saus and cornitermes cumulans kollar.
\nthe results demontrated that the insects have different sensivities to the various
\namides, with mortality ranging from 0 to 97.5% according to the compound
\nand insect species.<\/p>\n
\nanalen der chemie und pharmacie 1869 152: 25-58
\n\u00abuntersuchungen ueber die constitution des piperins und seiner
\nspaltproducte piperinsaeure und piperidin – erste abhandlung\u00bb<\/strong>
\nrud fittig, w h mielck<\/p>\n
\n(1) piperine from black pepper (2) hydrolysis of piperine to piperic acid<\/a>
\nhttp:\/\/www.rhodium.ws\/chemistry\/piperine.txt<\/p>\n
\n\u00abpiperine to piperonal procedure\u00bb<\/a>, the cook
\nhttp:\/\/www.rhodium.ws\/chemistry\/piperine.txt<\/p>\n