Author Topic: LiEt3BH reduction (Read 101 times)

devongrrl · « **on:** December 27, 2011, 08:45:45 PM »

I see in Tihkal that Shulgin suggests a possible synthetic route from tryptamine to DMT via a quaternary ammonium salt which is then reduced by Lithium Triethyl borohydride.

I'm wondering if the LEBH is mandatory, would LAH or NaBH4 be less effective where LEBH is unavailable ?

lugh · « **Reply #1 on:** December 28, 2011, 12:28:10 AM »

Quote

I'm wondering if the LEBH is mandatory, would LAH or NaBH4 be less effective where LEBH is unavailable ?

Perhaps, the former chief bee's comments on alternatives:

Rhodium
(Chief Bee)
03-20-03 00:50
No 419195
Why it is hard to reductively alkylate Tryptamine

I would reccommend this article: https://www.rhodium.ws/pdf/sodium.cyanoborohydride.pdf

On page 141, there is an example of tryptamine being reductively alkylated with an aldehyde and NaBH3CN, and in section 5 on page 137 it is explained why the reduction works so well with NaBH3CN.

One of the main reasons for other reducing agents not working as good is that some reduce the indole ring of tryptamine to an indoline, see https://www.rhodium.ws/pdf/nabh4.carboxylic.acids.pdf for example. Another limitation is that tryptamine and aldehydes under acidic conditions undergoes a so-called pictet-spengler cyclization, forming a tetrahydro-beta-carboline instead of the desired product, therefore all common reductive aminations using acid conditions won't work.

It's possible that other pertinent articles have been published since 2003, only an exhaustive search will settle that issue

The subject was discussed quite often in the Hive's Tryptamine forum

devongrrl · « **Reply #2 on:** December 28, 2011, 11:20:51 AM »

Excellent ! Thanks all

Oh and wishing every one a vespiarian New Year

(I couldn't think of a suitable Adjective)

Author Topic: LiEt3BH reduction (Read 101 times)

devongrrl

LiEt3BH reduction

lugh

Re: LiEt3BH reduction

devongrrl

Re: Re: LiEt3BH reduction