The Vespiary
The Hive => Methods Discourse => Topic started by: thefips on March 01, 2004, 08:24:00 AM
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Hi!
I have some questions on the synthesis of 3,4,5-trimethoxybenzaldehyde from 5-Hydroxyvanillin.For this synthesis I need dimethyl sulfate,and I searched the internet and also The Hive archive,but I didn´t find anything about the synthesis of dimethyl sulfate.But in the Rhodium archive there is something about the synthesis of diethyl sulfate from EtOH,H2SO4 and Na2SO4.Is the synthesis of dimethylsulfate analog to it,that I only have to calculate the amount of MeOH?Or has someone a synthesis for 3,4,5-trimethoxybenzaldehyde from 5-hydroxyvanillin in which another methylation agent is used,that ist less toxic and that could be made relatively easy?
And I thought about the synthesis of Syringaldehyde,in which sodium and MeOH are used to make 3,5-dimethoxy-4-hydroxy-benzaldehyde.The bromine ist substituted by a -O-Me group.
Can I make 3,5-dibromo-4-methoxybenzaldehyd from bromine and anisaldehyde and convert it into 3,4,5-trimethoxybenzaldehyde using MeONa?
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You haven't been looking enough. There are many threads dealing with (MeO)2SO2 synthesis. Some are even still active. If you would look enough you would find out why you need diethylsulphate.
Can I make 3,5-dibromo-4-methoxybenzaldehyd from bromine and anisaldehyde and convert it into 3,4,5-trimethoxybenzaldehyde using MeONa?
How would you introduce two bromines on anisaldehide? One would go but it would further deactivate the aromatic ring. Maybe a FeBr3 catalist would help to introduce the second one, but I'm not sure if the substitution would be selective for the position 5. Besides the symultaneous aromatic nucleophylic substitution of two bromines sounds a little low yielding. And also, maybe a phenolic group is a requirement to stabilise the radical intermediates with copper catalisys as I never so anything similar done on a non-phenolic benzaldehide.
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Can I make 3,5-dibromo-4-methoxybenzaldehyd from bromine and anisaldehyde and convert it into 3,4,5-trimethoxybenzaldehyde using MeONa?
There was a bee(GPig or something like that) who tried to make 3,5-dibromo and he had some trobles getting anything but a small yeild and he had analytical instruments available. Thats not to say it isn't possible and very interesting at that.