Dequaternization with ethanolamine

Hello - this is my first post here, let me know if it would belong better somewhere else!

I am interested in the dequaternization of ammonium salts (such as everyone's favorite trimethyltryptammonium iodide) to tertiary amines. This has been accomplished on simple substrates with various strong nucleophiles, such as sodium thiophenoxide[1] and DABCO[2].

These reagents are hard to get, but ethanolamine is more easily available. Hunig and Baron [3] describe dequaternization in neat ethanolamine of various species in reasonable yields (from what I can gather from Google Translate). Although I have seen this method recommended on this and other forums, I have not been able to find any amateur writeup using boiling ethanolamine.

I wonder if the success of the ethanolamine method hinges on the in-situ production of stronger nucleophiles such as piperazine and DABCO? If so, traces of water in the ethanolamine might slow down the dequaternization considerably. Yields and/or reaction times might be improved by adding molecular sieves: 1) to sequester water, and 2) since zeolites act as catalysts for the production of piperazine/DABCO from ethanolamine [4].


Does anyone here have experience using any of these nucleophiles for dequaternization? I'd love to hear it.




Refs:
[1] Shamma et.al., Tetrahedron Lett. 1966, 7(13), 1375-1379
[2] Kline et.al., J. Med. Chem. 1982, 25 ,908-913
[3] Chem. Ber. 1957, 90(3), 403-415
[4] Patent EP0313753A2