From: Eric J. Leopold (ejlmp$##$earthlink.net)
Date: Thu May 11 2006 - 22:41:23 EDT
On May 11, 2006, at 7:48 AM, Sunil Silvary wrote:
> Dear Sir/Madam,
> I want to know what precautions/safety measures should be
> taken while using LDA (lithiumdiisopropylamide) and
> trimethylsilylchloride (chlorotrimethylsilane).
>
> Thanks,
> Sunil
> --
> "If God does not exist, then you lose nothing by believing in Him.
> If he does exist, one loses everything by not believing. "
>
Dear Sunil,
LDA available from Aldrich as 97% concentration is spontaneously
flammable in air. Other forms of LDA as 10%wt suspension in hexane,
30%wt suspension in mineral oil both would not burn in air as the 97%
product. You can make your own LDA to get around the expense of LDA
from diisopropyl amine (1.54 mL, distilled from CaH2) in THF (20 mL,
dried & distilled from Na with di- benzophenone indicator) cooled
-40ºC (system under N2) and 6.6 mL of n-butyl lithium in hexane
(1.56M) is added drop wise. LDA formed is then ready to use. Good luck.
All the best,
Eric
How to cleave a peptide from a resin without using hydrofluoric acid:
<http://home.earthlink.net/~ejlmp/TMSX1.html>
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