|[3D .mol structure]|
A solution of 1.50 g 3-methoxy-4,5-ethylenedioxybenzaldehyde in 6 mL acetic acid was treated with 1 mL nitroethane and 0.50 g anhydrous ammonium acetate, and held on the steam bath for 1.5 h. To the cooled mixture H2O was cautiously added until the first permanent turbidity was observed, and once crystal-lization had set in, more H2O was added at a rate that would allow the generation of additional crystals. When there was a residual turbidity from additional H2O, the addition was stopped, and the beaker held at ice temperature for several h. The product was removed by filtration and washed with a little 50% acetic acid, providing 0.93 g 1-(3-methoxy-4,5-ethylenedioxyphenyl)-2-nitropropene as dull yellow crystals with a mp of 116-119 °C. Recrystallization of an analytical sample from MeOH gave a mp of 119-121 °C.
A stirred suspension of 6.8 g LAH in 500 mL anhydrous Et2O under an inert atmosphere was brought up to a gentle reflux. A total of 9.4 g 1-(3-methoxy-4,5-ethylenedioxyphenyl)-2-nitropropene in warm Et2O was added over the course of 0.5 h. Refluxing was maintained for 6 h, and then the reaction mixture was cooled and the excess hydride destroyed by the cautious addition of 400 mL 1.5 N H2SO4. The two clear phases were separated, and the aqueous phase was brought to pH of 6 by the addition of a saturated Na2CO3 solution. This was filtered free of a small amount of insolubles, and the clear filtrate was heated to 80 °C. To this there was added a solution of 9.2 g picric acid (90% material) in 100 mL boiling EtOH, and the clear mixture allowed to cool in an ice bath. Scratching generated yellow crystals of the picrate salt. This salt was filtered free of the aqueous environment, treated with 50 mL of 5% NaOH, and stirred until the picric acid was totally in the form of the soluble sodium salt. This was then extracted with 3x100 mL CH2Cl2, the extracts pooled, and the solvent removed under vacuum. The residue weighed 6.0 g, and was dissolved in 100 mL anhydrous Et2O, and saturated with dry HCl gas. The white solids that formed were filtered free of the Et2O, and ground up under 50 mL of slightly moist acetone, providing 4.92 g of 3-methoxy-4,5-ethylenedioxyamphetamine hydrochloride monohydrate (MEDA) as white crystals.
DOSAGE: greater than 200 mg.
EXTENSIONS AND COMMENTARY: There are times when the Gods smile in unexpectedly nice ways. Having found the activity of MMDA, the "scientific" thing to do would be to compare it against the other "psychotomimetic" amphetamine that was known at that time (this was 1962), namely TMA. Comparing their structures, the only difference of any kind was that two of the adjacent methoxyl groups of TMA were replaced with a 5-membered ring, called the methylenedioxy ring.
Where does one go next? Some perverse inspiration suggested increasing the size of this ring to a 6-membered ring, the ethylenedioxy (or dioxene) homologue. Well, if you thought that getting myristicinaldehyde was a difficulty, it was nothing compared to getting this 6-membered counterpart. But I huffed and I puffed, and I did make enough to taste and to evaluate. And it was here that I got the divine message! No activity!! So, rather than being condemned forever a la Sisyphus to push ever larger rings up my psyche, I gave myself permission to pursue another path. The message was: "Don't change the groups. Leave them as they are, but relocate them instead." And that led directly to TMA-2 and its story.
A couple of diversions may be mentioned here. Before the blessed inactivity of MEDA was established, the 7-membered ring counterpart, 3-methoxy-4,5-trimethylenedioxyamphetamine (MTMA) was prepared by essentially the same procedure. The above 3-methoxy-4,5-dihydroxybenzaldehyde with trimethylene bromide gave 3-methoxy-4,5-trimethylenedioxybenzaldehyde, white solids, with a malononitrile derivative with a mp of 134-135 °C; the aldehyde with nitroethane gave the nitropropene with a mp of 86-87 °C; and this with LAH gave MTDA as the hydrochloride (mp 160-161 °C) again isolated first as the picrate. It had been tasted at up to an 8 milligram dosage (no activity, but none expected) before being abandoned. And, an initial effort was made to synthesize a five-member ring (methylenedioxy) with a methyl sticking out from it. This ethylidine homologue got as far as the aldehyde stage. The reaction between 3,4-dihydroxy-5-methoxybenzaldehyde and 1,1-dibromoethane in acetone containing anhydrous potassium carbonate gave a minuscule amount of a product that was a two-component mixture. This was resolved by dozens of separate injections into a preparatory gas chromatography system, allowing the isolation of the second of the two components in a quantity sufficient to demonstrate (by NMR spectroscopy) that it was the desired 3-methoxy-4,5-ethylidinedioxybenzaldehyde. Starting with the pre-prepared dipotassium salt or the lead salt of the catecholaldehyde gave nothing. With no activity being found with MEDA, all was abandoned.
There are some comments made under MDA for successful chemistry (using a different approach) alo#ng these lines when there is no methoxyl group present. These are the compounds EDA and IDA. But the pharmacology was still not that exciting.
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