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