I think ozonolysis is a possibility. Patents exist for the manufacture of piperonal from safrole. Strike forgets that dichromate is 1) not OTC and 2) produces toxic chromate waste products. But... ozonolysis is difficult to control.
dpHarma
When you say difficult to controll is that as in by-products, or explosions?
using K2Cr2O7 (like SP said): 'J.Chem.Ind.Tokyo' 23 p56-79 (1920).
Good luck finding that second reference!
With ordinary solutions of permanganate or dichromate the yields are generally low and the reaction is seldom a useful synthetic method; but high yields can be obtained by oxidising with KMnO4 dissolved in benzene containing the crown ether dicyclohexano-18-crown [J. Am. Chem. Soc. 94, 4024 (1972); J. Org. Chem. 43, 1532 (1978)
With certain reagents the oxidation can be stopped at the aldehyde stage, and in these cases the products are the same as the ozonolysis procedure. Among these reagents are:
chromyl trichloroacetate: Liebigs Ann. Chem. 659, 20 (1962)
t-butyl iodoxybenzene: Tetr. Lett. 26, 4955 (1985)
KMnO4 in THF-H2O: J. Org. Chem. 51, 3213 (1986)
NaIO4-OsO4: J. Org. Chem. 21, 478 (1956)
That KMnO4 in THF looks very enticing - I'll mail the procedure ASAP.
The supposed knock on that was that the permanganate would overoxidize the p'fed...blahblahblah
but it doesn't if treated correctly.
diluting the FUCK out of it and chilling it seems to really take a lot of oomph out of the Rx.....????
MDP-acetyl carbinol is easily reduced to b-Me-MDP-glycol, from which MDP2P can be obtained by our dear friend the Pinacol rearrangement. The total process is untried so yields are as yet unknown. But everything is very OTC.
Piperonal can, itself, be obtained by oxidation of piperic acid (from pepper) with KMnO4 in THF or with PTC. [see the references above, in my previous post]. The amount of KMnO4 used must be strickly limited so as not to over-oxidise to the MD-benzoic acid.
I hope to get this patent next Monday.
L(-)3,4-Dimethoxyphenylacetyl carbinol (3,4-(MeO)2C6H3CH(OH)Ac) is produced by contacting veratraldehyde with a growing acyloin-producing culture of Aerobacter aerogenes ATCC 211; the product is isolated by extn. and crystn. Thus, medium contg. com. yeast ext. 20, dextrose 20, MgSO4 7 H2O 0.5, KH2PO4 0.2, and Na2HPO4 0.2 g./1., with pH adjusted to 7, is inoculated with a strain of Saccharomyces cerevisiae; the medium is aerated and agitated at 28° for 48 hrs. The agitation and aeration are stopped. Vanillin is added to give a concn. of 4 g./1. The agitation and aeration are resumed and continued for 7 hrs. to produce L-3,4-(methylenedioxy)phenylacetyl carbinol. The fermentation broth is sterilized and filtered to remove the cells. The filtrate is satd. with NaCl and extd. 4 times with 1/3 vol. of EtOAc. A crude product is obtained after evapg. the EtOAc. A by-product of the fermentation process is removed by crystn. from an EtOAc-petroleum ether soln. of the crude product. The mother liquor contains the desired product, the solvents are removed by evapn. and the residual oil is subjected to partition column chromatog. using diatomaceous earth and a solvent mixt. of C6H6-EtOAc-MeOH-H2O (9:1:5:5). The fractions eluted are vanillyl alc., vanillin, and a mixt. of vanillic acid and L-3-methoxy-4-hydroxyphenylacetyl carbinol. The last fraction is fractionally crystd. from a mixt. of EtOAc-petroleum ether to remove vanillic acid. The mother liquor contg. the product is further purified by extn. by aq. Na2SO3 to ext. acetyl carbinol as a bisulfite. The bisulfite addn. product is decompd. by addn. of an excess of an aq. soln. of Na2CO3. The product is extd. with EtOAc. The ext. is evapd. to a small vol. to cryst. L-3-methoxy-4-hydroxyphenylacetyl carbinol; m.p. 69-73°, [a]D23 = 211° (c 1.02%, acetone). L-3,4(Methylenedioxy)phenylacetyl carbinol, m.p. 44-6°, [a]D25 = 228° (c 1.2% EtOAc), and L-3,4-dimethoxyphenylacetyl carbinol were also produced by the method. S. P. Marino
Isolation of Piperine from Black Pepper - J. Chem. Ed. 70(7), 598-9 (1993)
Hydrolysis to Piperic acid (might not be needed (at Rhodium's)
Oxidative cleaveage to Piperonal with cetyltrimethylammonium permanganage - see Synthesis 1984, p 431-3. They also give details for making CtMe3N MnO4 from CtMe3NBr - but I can't see why CtMe3NCl shouldn't work just as well (CtMe3NCl is ubiquitous in loads of OTC skin & Hair products) - I intend to try this first with fabric conditioner - it's cheaper but is less hydrophilic (so might not work!).
Also J. Chem Research - Synopses 1986, p 458-9 for "Cetyltrimethylammonium Permanganate: a Useful Reagent for the Selective Oxidative Cleaveage of Aryl-substituted Olefins"
R4N+ MnO4- is one reagent to use - expected yield of piperonal ~ 74% with this:
The benzylic alkene of piperic acid should cleave to aldehydes (either side) and other, purely aliphatic alkene group will give a diol.
Alternatives are to use (2) aq. KMnO4 with substrate in THF - it might work - see J. Org. Chem. 51, p 3213 (1986). Or (3) PTCs, which include: Crown ethers (too expensive), TDA-1 - see Synthetic Commumications 17 p 647-55 (1987), Dimethyl polyethylene glycol - see J. Org. Chem. 43, p 1532, (1978).
General Procedure for the Oxidative Cleavage with CTAP
To a stirred solution of the alkene substrate (1 mmol) in DCM (7 mL) was added a solution of CTAP (1 mmol) in DCM (6 mL) at 25°C. After 2-6 h, diethyl ether (50 mL) was added and the reaction mixture was filtered through a pad of Celite and anhydrous MgSO4. The filtrate was concentrated in vacuo and the crude product was purified by chromatography on silica gel to afford the pure carbonyl product. [From: J. Chem. Res. (S), 1986, 459]
Note (mine): CTAP: cetyltrimethylammonium permanganage.
Why do they add diethyl ether and not more DCM? Surely better to stick with just one solvent so that it can be recycled?
Cetyltrimethylammonium Permanganate, CTAP
To a stirred solution of potassium permanganate (3.168 g, 20 mmol) in water (100 mL) at 20°C is added, dropwise over 20 min, a solution of CTAB - Cetyltrimethylammonium Bromide (8.02 g, 22 mmol) in water (100 mL). A fine violet precipitate forms immediately. Stirring is continued for 30 min, the precipitated product is isolated by suction, washed thoroughly with water, and dried in a dessicator over phosphorus pentoxide in vacuo for 3 h at room temperature to give the salt as a fluffy violet solid; yield: 6.5 g (80%). The reagent is stored in a brown bottle in the refrigerator. [From Synthesis 1984, p 431]
Notes: a suitable alternative to CTAB is CTAC aka Cetrimide or Cetrimonium Chloride - found in hair conditioners. [A small cosmetics company would have no difficulty getting hold of mucho supplies of this in mega quantities]
An alternative dessicant to the P2O5 is KOH or NaOH? Why not? Dessication is essential and these quaternary ammonium compound are very hygroscopic.
1)As they filtered the pepper from the IPA..
"Damn this shit smells peppery"
2)One got the yellow pepper extract on his face...
"Ouch, this burns like pepper on my face"
3)After the acetone wash of above extract.
"Boy, that's bright yellow"
4)When they boiled the yellow extract with bicarb...
"Look! 2 layers! How'd that happen"
5)After above reflux
"What happened to my yellow powder? All I have now are whitish crystals!"
6)While adding the permanganate...
"Hey, that funky pepper smell is changing into a more pleasant odor!"
7)After yellow oil extraction...
"This doesn't smell like pepper very much at all!"
8) While playing with room temp melting point.
"This stuff should be kept in the freezer!"
Once again, I apologize for any and all typos, and sorry I didn't have their measurements, the program said it would make the whole game too easy.. Post any related dream stories. This seems to be QUITE ineffiecient, but if blk pepper is $5.00 a pound, it ain't that bad. Plus, it's OTC.
*I miss ZWITTERION's kitchen chemistry tales.
This guy here :
http://www.lycaeum.org/~rhodium/chemistry/piperine.txt (http://www.lycaeum.org/~rhodium/chemistry/piperine.txt)
seems to have had trouble with the oxidation of Piperic Acid via KMnO4, reporting *piperonyl, piperonylic acid and/or piperonyl acetone in varying quantities.*
Would some sort of catylised Oxidation work better? Someone recently said something about KMnO4 being non-selective. Perhaps there is a better route?
If this could be made to work in reasonable yeilds youd be looking at Piperonal OTC for $100/Kilo.
Perhaps its not that tempting now, but in a few years it may be.
So has anyone got any ideas?
Post 165774 (https://www.thevespiary.org/talk/index.php?topic=6859.msg16577400#msg16577400)
(Cherrie Baby: "Oxidation of Piperic Acid (Pepper to Piperonal)", Chemistry Discourse)J. Org. Chem. 51, 3213-3214 (1986) (https://www.thevespiary.org/rhodium/Rhodium/chemistry/alkene2aldehyde.kmno4-thf.html)
(https://www.thevespiary.org/rhodium/Rhodium/chemistry/alkene2aldehyde.kmno4-thf.html)