Re: ORGLIST:

Date view Thread view Subject view Author view Attachment view

From: Jacob Zabicky (jzabicky$##$etseq.urv.es)
Date: Wed Oct 07 1998 - 13:36:21 EDT


Hello Barnabas,

It's worthwhile repeating the experiment! Before getting too involved in
possible explanations, it would be very helpful having a look at the
experimental of the paper, and especially at the degree of purity of A. The
particular batch that was used might have been of dubious quality.

Good luck,

Jacob

>Dear colleagues,
>i read of an article, syn comm 23(10),1351-1356(1993)and am quite
>puzzled with the results obtained.the following is the summary of the
>paper:
>Nitration of 2,5- Dimethoxybenzaldehyde [ named as A]
>
>1) A ---------.> 3,5- Dimethoxy-2-nitrobenzaldehyde (64%) +
> 2,5- Dimethoxy-4-nitrobenzaldehyde (26%)
>
>2) A----------> MIXTURE OF mono, di and trinitro compound
>
>3) A----------> 3,5- Dimethoxy-2-nitrobenzaldehyde (60%) +
> 2,5- Dimethoxy-4-nitrobenzaldehyde (29%) +
> 2,5- Dimethoxy-3-nitrobenzaldehyde (5%)
>condition for
>1)70% HNO3 as solvent and nitrating agent, stirred at RT for 3 hrs.
>3)70 % HNO3 Et20 as solvent + acetic acid, stirred at RT for 30 hrs.
>my question is ,
>why should 3,5- Dimethoxy-2-nitrobenzaldehyde be the major compound in
>both cases in viewof the fact that it may be affected by steric
>hindrance.(moreover -CHO is a meta director)
>my opinion is 2,5- Dimethoxy-3-nitrobenzaldehyde should be the major
>product.
>could anyone please offer me some possible explanation? and is there any
>other condition where one can get
>2,5- Dimethoxy-3-nitrobenzaldehyde as major product?
>
>Grateful to get some reply.
>Thanx in advance,
>Barnabas
>
>
>______________________________________________________
>Get Your Private, Free Email at http://www.hotmail.com
>__________________
>
>ORGLIST - Organic Chemistry Mailing List
>WWW Homepage and Archive: http://www.orglist.net/
>List coordinator: Joao Aires de Sousa (jas$##$mail.fct.unl.pt)



__________________

ORGLIST - Organic Chemistry Mailing List
WWW Homepage and Archive: http://www.orglist.net/
List coordinator: Joao Aires de Sousa (jas$##$mail.fct.unl.pt)



Date view Thread view Subject view Author view Attachment view

This archive was generated by hypermail 2.1.4 : Fri Sep 19 2003 - 12:14:43 EDT