From: Sengen Sun (sengensun$##$yahoo.com)
Date: Mon Nov 27 2006 - 14:38:48 EST
I would expect this particular one is very tough. I
would believe you if you got "excellent results"
exactly with PhCH2CH2Br.
All the suggestions by Sachin are worth trying if the
alkylating agent is one of allyl or benzyl type.
There is a literature example with unactivated alkyl
bromide in the selective C-alkylation:
Synth. Commun. 1982, 861. They used Me3OBF4 as the
reagent to give 1-37% yield. But it is a different
situation, may or may not work for yours.
Good luck,
Sengen
--- Sachin Chaphekar <purvi_chaphekar$##$yahoo.com>
wrote:
> Dear Kamal,
>
> Did you try K2CO3 in acetone and preferably in
> presence of a PTC? K2CO3 works very well in acetone.
> You will have to use excess (2-2.5 moles) since
> there is a -COOH gr. as well. Otherwise, try
> pyridine as an HBr scavenger, N,N'-diethylaniline
> also works equally well. alkoxides are pretty strong
> and you will get messy substances. I don't think its
> a too difficult a reaction. In some of cases I have
> got excellent results simply by refluxing the halide
> and substrate in either dichloromethane or ethyl
> acetate or even THF.
>
> Good luck,
>
> Sachin
>
> ----- Original Message ----
> From: Kamal Morendha <mailbox$##$prolificint.com>
> To: everybody$##$orglist.net
> Sent: Wednesday, November 22, 2006 4:57:14 PM
> Subject: ORGLIST: Alkylation with Ph-Et-Br
>
>
> Hi !
>
> I'm doing one alkylation reaction involving
> N-Ethoxycarbonylmethyl-L-Valine & 2-Phenylethyl
> Bromide as under :
>
>
> EtOOC-CH2-NHCH-CH(CH3)2-COOH + 2-PhCH2CH2Br
> -------> EtOOC-CH(CH2CH2Ph)-NHCH-CH(CH3)2-COOH
>
>
> I tried using K2CO3 in diff. solvents, Na-EtOH, but
> could not get the conversion at all.
>
> May I get some suggetions for this Alkylation ?
>
>
>
> Thanks,
> Kamal
>
>
>
>
>
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