Like you say, there are quite a few Far East companies out there who stock ring substituted benzaldehydes.
As long as you provide a legitimate explanation for needing it, I can't really see any problem - even with the US.
Domestic resale to the research community would be an innocous reason. Why not set up a company and have a few brochures printed with other specialized chems for sale? Say you've identified a 'niche' market.
Just don't go converting it to anything else straight away. Let it sit around for a while and be suspicious of those pizza delivery vans parked down the street.
Incidentally, 3,4,5-trimethoxybenzaldehyde is widely used to manufacture pharmaceuticals. Have to check on legitimate uses for 2,5-dimethoxy.
To get an idea of annual use, try asking a few of the Asian Co's they annual capacity. This will at least give you an idea of the world market for this chemical.
chemE.
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