That route has several drawbacks which make it impractical for clandestine synthesis. The first and most important problem is the availability of 2,4,5-trimethoxybenzaldehyde. This substance is not exactly a linchpin of chemical commerce. So far as I know, it has one use: making TMA-2. Those same folks who gave me the hassle over the purchase of Rochelle salts will certainly report a shipment of 2,4,5-trimethoxybenzaldehyde, and the heat will not be far behind. Further chemical supply problems arise from this method's use of large amounts of anhydrous ether or THF in the LiAlHj reduction. This too will be duly noted by the heat, especially in combination with buying LiAlHt.
A much more low-profile synthetic route is possible using calamus oil as the raw material. A couple of patents granted in the late 80s have completely changed the field of psychedelic amphetamine manufacture from the way Dr. Shulgin knew it during his days of cooking in the 60s. Previous to the publication of these patents, the Knoevenagel condensation of benzaldehydes to yield the nitroalkene, followed by the reduction of the nitroalkene to the amphetamine, was far superior to an alternative route making use of the common essential oils.
The alternative route was to take this substituted allylbenzene, move the double bond to the propenyl position by heating with anhydrous alcoholic KOH, yielding in the case of safrole, isosafrole. Then a messy, tedious and low-yield reaction was used to convert this propenylbenzene to the corresponding phenylacetone. All we veteran speed cooks love phenylacetones, because they offer the cleanest and best route to the amphetamines, but the old-fashioned method of
converting propenylbenzenes to phenylacetones made this route impractical:
My own experience with this reaction dates to the early 80s, when I decided to torment myself by trying it. Detailed cooking procedures using it can be found in Pikhal under MDMA. My experience with the KOH isomerization was that the conversion of safrole to isosafrole went cleanly at about 100% yield, as long as traces of moisture were excluded from the reaction. The conversion of isosafrole to methylenedioxy-phenylacetone is another matter. The yields are low, a lot of work is required because the formic acid and hydrogen peroxide must be removed from the reaction mixture under a vacuum before final treatment with sulfuric acid solution to yield the phenylacetone, and these vapors corrode the aspirator supplying the vacuum. This method stinks!
Two patents dating to the late 80s, and to a lesser extent a journal article dating back to 1970, have turned the situation around. The first patent I will cite is US patent 4,638,094, titled "A Process for Producing Phenylacetones." This patent reveals, using many different examples over the course of 36 pages, the best general method for converting allylbenzenes to the corresponding phenylacetone in very high yields.
This procedure reacts the allylbenzene (for example safrole, as obtained in pure form by vacuum distilling sassafras oil) with methylnitrite in methanol solution containing water and a palladium catalyst to yield the phenylacetone. The palladium catalyst can be used in a variety of forms, as detailed in the patent. The best choices
for use with safrole are palladium bromide, chloride, or a mixture of palladium chloride and copper chloride. Of the three, the mixture catalyst is better for reasons which will be explained in the following cooking example:
In a 4000 ml beaker, or one-gallon glass jug, is placed 3000 ml methyl alcohol, 150 ml safrole, 300 ml distilled water, and the chemist's choice of either 20 grams palladium bromide or ten grams of palladium chloride or a mixture of one gram palladium chloride and 4.25 grams copper chloride (CuCk). The catalyst choices have been given here in order of good to best. The reason why the last choice is best is because of the very high cost of palladium salts. Palladium chloride is preferred over the bromide because palladium chloride finds use in the electroplating field. It is used there in baths to plate palladium, and as part of the activation process to prepare plastics to be plated. The bromide is not as commonly used.
Next, a methyl nitrite generator is rigged up as shown in Figure 3:
Into the 2000 ml flask is placed one pound of sodium nitrite, 225 ml of methyl alcohol, and 260 ml of water. They should be swirled around for a while to mix. Then 680 ml of cold dilute sulfuric acid (made by adding 225 ml of sulfuric acid to 455 ml of distilled water, mixing and chill-ng) is put into the dropping flannel.
Now vigorous | magnetic stirring is begun in the beaker or glass jug containing the Figure3
allylbenzene-alcohol-pal- Methyl nitrite generator
In the 1-mole batch given in this example, about 6 moles of methyl nitrite are bubbled into the reaction mixture, while only 2 are required for the reaction. The reason for the excess is because methyl nitrite is not held in solution very well on account of its very low boiling point. If ethyl nitrite was used instead, then only three or four moles would be needed.
While the reaction is being done, the mixture takes on the appearance of mud if palladium bromide is being used. A fizzing also
occurs, which gives the reaction mixture the appearance of freshly poured Coke. Note above that a bit of acid is required to get hydrolysis of the intermediate dialkoxyphenylpropane to the phenyl-acetone. The best pH for this reaction is between 4-7. If palladium chloride or the mixed catalyst PdCh-CuCla is being used, the pH of the reaction mixture can be adjusted to this range by adding a small amount of HC1. If PdBr2, is used, it is best to wait until the catalyst is filtered out before adding HC1, as the HC1 could form PdCh and complicate catalyst recovery. The pH of the reaction mixture is best measured by first dampening some indicating pH paper with distilled water, then putting a drop of reaction mixture on the paper. The preferred temperature for this reaction is about 25 C throughout.
When all the methyl nitrite has been bubbled into the reaction mixture, stirring should be continued for another hour. Then, if palladium bromide was used, it should be filtered out. Repeated filtrations will be needed to remove all of the catalyst, because it gets quite finely divided during the course of the reaction. This leaves a clear light-reddish solution. If palladium bromide was used, now adjust pH to 4-7, and allow another hour to complete the hydrolysis.
If palladium chloride or the mixed catalyst was used, these substances are soluble in alcohol. In this case, the catalyst will be recovered later. Here, check the pH of the solution again to be sure it is in the proper range before proceeding.
Now the alcohol solvent must be removed. This is best done by pouring the reaction mixture into a large filtering flask, stoppering the top of the flask, and removing the solvent under a vacuum. Use of a hot-water bath to speed evaporation is highly recommended for this process. It is not OK to distill off the alcohol at normal pressure, as the heat will cause the nitrite and NO in solution to do bad things to the product.
To the residue left in the flask after removal of the alcohol, add some toluene to rinse the product out of the flask into a sep funnel. Next, put 300 ml of water into the flask to dissolve the catalyst if PdCla or the mixed catalyst was used. Add the water solution to the sep funnel to dissolve carried-over catalyst there, then drain this water
solution of catalyst into a dark bottle and store in the dark until the next batch. If PdBr2 was used, this step can be skipped. Just store the filtered-out PdBra under water in the dark.
Now the toluene-phenylacetone solution should be distilled through a Claisen adapter packed with some pieces of broken glass to effect fractionation. The first of the toluene should be distilled at normal pressure to remove water from solution azeotropically. The b.p. of the azeotrope is 85 C, while water-free toluene boils at 110 C. When the water is removed from solution, turn off the heat on the distillation, and carefully apply a vacuum to remove the remainder of the toluene. Then with the vacuum still on, resume heating the flask, and collect the substituted phenylacetone. Methylenedioxyphenyl-acetone distills at about 140 C and 160 C using a good aspirator with cold water. A poor vacuum source leads to much higher distillation temps and tar formation in the distilling flask. The yield from the reaction is close to 150 ml of phenylacetone. Its color should be clear to a light yellow. The odor of methylenedioxyphenylacetone is much like regular phenylacetone, with a trace of the candy shop odor of the safrole from which it was made.
A higher-boiling phenylacetone like 2,4,5-trimethyloxyphenyl-acetone is better purified as the bisulfite addition product, unless a vacuum pump giving high vacuum is available. To make the bisulfite addition product, take the residue from the filtering flask, dissolved in some toluene and freed from catalyst as described above, and pour it in a beaker. Next, add 3 volumes of sodium bisulfite solution prepared by adding sodium bisulfite or metabisulfite to water until no more dissolves. Shake or vigorously stir for a couple of hours to convert the phenylacetone to the solid bisulfite addition product. Filter out the solid, then regenerate pure phenylacetone by putting the solid into a round-bottom flask, adding an excess of saturated solution of sodium bicarbonate in water, and refluxing for a couple hours. After cooling, the phenylacetone should be extracted out with some toluene. The toluene should then be removed under a vacuum, and the residue stored in a freezer until conversion to the amphetamine. All
phenylacetones are sensitive to light, and should be stored in the freezer.
The above cooking procedure is the best way to process allylbenzenes to the corresponding phenylacetones. Sassafras oil, as previously mentioned, is 80-90% safrole. Calumus oil, if its country of origin is India, consists of about 80% of the allyl isomer of asarone:
It too can be purified by distillation under a vacuum to yield fairly pure allyl-asarone. Its boiling point is 296 C at normal pressure and about 170° C with aspirator vacuum. More details on this Indian calamus oil can be found in Chetn. Abstracts column 6585 (1935), also Current Science, Volume 3, page 552 (1935).
My search for calamus oil of Indian origin came up empty. In fact, the health-food store in my town, which is well-stocked with various oils for use in aromatherapy, had never heard of the stuff, nor was it listed for sale in their catalogs. This left one alternative: dig up the roots of North American calamus, and steam-distill the oil out of them.
While searching for calamus in my area's swamps, bogs and ponds, the damaging effects of the spread of purple loosestrife was obvious. This imported plant from Europe has taken over much of the former habitat of the calamus plant. Here in America, the loosestrife is free from the insect that keeps it under control in Europe by feeding on its seeds. The state paper-pushers have been thinking for years about importing the bug, without ever getting off their butts and doing it. I suggest this project to somebody out there in the reading public so that it can finally get done while there is still some native flora left:.
After a lot of searching, I finally found a large patch of the American calamus. (See Figure 4.)
The time for harvesting the roots of the calamus is in the fall after the killing frost. The frost brings the oil down out of the leaves and
into the root for winter storage. The roots are about a foot long, an inch or so in diameter, and run horizontally in the soil at a depth of a few inches. They are best dug out using a fork, taking care not to pierce the root, as this will cause loss of oil during drying. The dug-up roots should be rinsed free of dirt, and the tops cut off there in the field. (See Figure 5.) The roots should then be taken home and allowed to dry at room temperature for a week or two. Take care that they do not get moldy!
Once dried, oil can be distilled from them. This is done by first grinding up the roots in a blender or with a Salad Shooter, and piling the ground-up roots into a large pressure cooker. A good-sized pressure cooker will take a load
Of 10-15 pounds Of
Calamus plant root and fibrous rootlets.
root. Next, add a few gallons ofwater, a couple handfuls ofsalt, and mix.
The oil can now be distilled. Attach a five-foot length of copper tubing to the steam exit on the lid of the pressure cooker. Its diameter should match that of the steam exit so that steam is not lost here, and should be tightened into place with a pipe clamp. The tubing should then be led downward into a pail of ice water, and back up into a
dark-glass 40 or 64 ounce beer bottle. The ice water cools the steam, turning it into water which collects in the bottles.
Heat is applied to 1he pressure cooker, bringing it to a boil. Heat as fast as is possible without bringing over foam or having uncondensed steam escape. When a couple of gallons have been distilled out, stop the heating and add a couple more gallons of water to the pressure cooker. Continue this process until 4-5 ¡^gallons of water have been collected.
This process is a steam distillation, and is the way most plant oils are obtained. The steam distillate in the beer bottles contains calamus oil floating on top of the water and clinging to the glass. Calamus oil produced from American plants is reddish brown, and has a strange, pleasant and sweet odor. For more detailed information on calamus oil see The Chemergic Digest August 30, 1943, pages 138-40, and Soap, Perfumery and Cosmetics August 1939, pages 685-88.
The oil is obtained by first saturating the steam distillate with salt, then extracting the oil with toluene (obtained off the shelf in the hardware store's paint section). About a gallon of toluene is plenty to effect the extraction. Then the toluene is removed by vacuum evaporation in a large filtering flask to yield the calamus oil as a
residue in the filtering flask after the toluene has been evaporated. The yield is about 200 ml from 15 pounds of roots.
Calamus oil obtained from sources other than India differs from the Indian oil in two important respects. The amount of asarone in the oil is much lower than the 80% found in the Indian oil, and the position of the double bond is propenyl rather than allyl:
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