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Demethylation of 3,4,5-trimethoxybenzaldehyde

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Rhodium:
5-Bromo-4-formyl-2-methoxyphenol is a rather cryptic and inappropriate name for
this molecule - I even had to draw it to be able to identify its structure.

Its structure and proper IUPAC name follows here below:

Manichi:
What is strange is that the nitration of the same acetoxy vanillin give the 2-nitro compound, that is 2-nitro-3-methoxy-4-hydroxy benzaldehyde...

I wonder why, I thought it was the acetoxy which gave this orientation, but apparently not...


Captain: why dont you alkylate vanillin before the bromination, the product orientation is 2,4,5 in that case... and you dont need to generate the 4-acetoxy of the vanillin... any write up for this from GAA?


good luck with the methylmercaptan swap, hehe it will have quite a smell  ;)

so much dark compound, TMA-2  ::)

Captain_America:
Yes, of course  ;) , just like in: Post 214376 (missing) (foxy2: "Re: 2 Bromination of 3,4-dimethoxybenzaldehyde", Chemistry Discourse)

So much darkness in so few miligrams... ;)

Rhodium:
4-Desmethylmescaline
A. Brossi and S. Teitel
Org. Prep. Proced. Int. 1(3), 171-172 (1969)

4-Desmethylmescaline, a potential metabolite of mescaline which occurs as a minor alkaloid in Lophophora williamsii and Trichocerus pachanoi1, has been prepared from syringaldehyde by a multistep procedure2. A more convenient route is the facile conversion of mescaline by selective demethylation with mineral acid to afford 4-desmethylmescaline in 64% over-all yield. This procedure is another example of the preferential cleavage of the middle methoxyl that has been demonstrated3,4 for various alkaloidal systems containing three neighboring methoxy groups.

Experimental

A solution of 8 g. (32.4 mmole) of mescaline hydrochloride in 100 mL of 20% hydrochloric acid is refluxed for 2 hrs. and evaporated at 40°C under reduced pressure. The residual oil is crystallized from 100 ml. of ethanol to give 2.4 g of 4-desmethylmescaline hydrochloride: mp 249-250°C. ?EtOHmax sh 230 nm (6500), 272 (1280); nmr (DMSO-d6, 60-Mc, tetramethylsilane) ? s 2.93 (2CH2), 3.76 (2CH3O), 6.53 (2 aromatics), 8.23 (OH and NH3); tlc (silica gel G, developed with 100:10:5 EtOAc-MeOH:NH4OH for 11 cm. and detected with Dragendorff's reagent), Rf 0.40; identical in m.m.p., uv, nmr and tlc to an authentic sample2. Mescaline hydrochloride (4 g.) is recovered by evaporation of the filtrate followed by crystallization from 100 ml. of acetonitrile. The overall yield of 4-desmethylmescaline hydrochloride is thus 64%.


References

[1] S. Agurell and J. Lundström, Chem. Commun., 1638 (1968)
[2] F. Benington, R. D. Morin, and L. C. Clarke, Jr., J. Amer, Chem. Soc., 76, 5555 (1954) Post 523232 (Rhodium: "Synthesis of Escaline and Homosyringylamine", Novel Discourse)
[3] A. Brossi, J. Van Burik, and S. Teitel, Helv. Chim. Acta, 51, 1965 (1968)
[4] A. Brossi, J. O'Brien, and S. Teitel, Helv. Chim. Acta, in press.

Captain_America:
Yes, but how would you alkylate the -OH w/o alkylating the amine too?

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