Dear Bottleneck!
What you have found is indeed awesome. Double awesome, in fact.
I think your mistake was not using the proper markup for the patents - it is just so much easier to click on a link rather than doing all that elaborate work
of finding a patent on Espacenet
And, generally, it is considered
bon ton on the Hive to supply some examples in addition to patent links.
Well, i have read both patents and i must say they offer a real breakthrough! I have also ventured to dig up all of the patents mentioned in them and they also have some real interesting tidbits.
The first one: it is the 1st patent ever to describe methylolation of a fully etherified phenol. The yield ain't all that great, but the procedure is EASY and also non-toxic. Which is makes it markedly different from chloromethylations. Together with azomethinic formylation (as in
Post 382264
(Antoncho: "Zealot: azomethinic (Haack) formylation", Novel Discourse)) this is currently one of the so few kitchen-chem methods that can bee used directly on phenol ethers.
Apart from that ... since Haack formylation also gives yields in 50-60% range, the method you've found is very valuable! A little more involved in terms of duration, but doesn't require gassing w/HCl and pre-preparation of reagents.
The second method does require pre-preparation of reagents (namely, chloral, which can bee made by simply chlorinating EtOH - of course, working w/chlorine in the kitchen is YUCK YUCK YUCK - but nonetheless quite realistic, much more bearable than with bromine
). And it works only on phenols. And it prefers being unhydrous.
BUT. It's also very, very nice. It is the only selective hydroxymethylation process i've seen thus far.
It's esp. interesting in relation to piperonal.
-OH group isn't that deactivating at all, which means it would bee easy to methylolate catechol, methylenate w/DCM in DMF (with GOOD yields) and then oxidize to aldehyde.
It would definitely bee SWIM's method of choice if he ever decided to make piperonal from scratch. Preferrable to vanillinic methods, i dare say.
Well, in addition to that i advise everyone interested to take a look at
Patent GB344675
which describes in detail how to oxidize BzOH's to BA's with copper salts. The would also bee definitely THE method of choice in kitchen conditions.
Bottleneck! Could you, maybee, correct the patent links in your above posts and supply the most relevant examples from the patents you've found so that they can bee rated as excellent and eventually make it to Rh's site.
Sincerely Yours,
Antoncho