Print Page - Clarke-Eschweiler reaction

Title: Clarke-Eschweiler reaction
Post by: PEYOTE on June 18, 2000, 10:27:00 PM

To obtain N,N-dimethyl alkanes form R-NH2, you can use the reaction of Clarke-Eschweiler
using HCOOH and CH2O in polymeric form....

Title: Re: Clarke-Eschweiler reaction
Post by: Rhodium on June 18, 2000, 10:33:00 PM

This won't work with tryptamine. Formaldehyde and acid will lead to a pictet-spengler cyclization, forming a beta-carboline.

http://rhodium.lycaeum.org (http://rhodium.lycaeum.org)

Title: Re: Clarke-Eschweiler reaction
Post by: Lilienthal on June 18, 2000, 10:35:00 PM

But not for tryptamines, since they will cyclize to beta-carbolines under this conditions (Pictet-Spengler reaction) :( .

Title: Re: Clarke-Eschweiler reaction
Post by: PEYOTE on June 18, 2000, 10:51:00 PM

I'd like to know more of this cyclization..... thanks...

Title: Re: Clarke-Eschweiler reaction
Post by: Rhodium on June 19, 2000, 12:08:00 AM

Like this,

http://home.ici.net/~hfevans/reactions/RXN300.htm (http://home.ici.net/~hfevans/reactions/RXN300.htm)

but instead the new carbon-carbon bond is formed between the formaldehyde imine and the 2-position of the indole nucleus.

The Vespiary