Wouldn't butanol give some butyl ester by transesterification? Probably no big deal for diethylbarbituric acid, unless one wants ester purified by
distillation.
BTW the OP offsite link is not a quote from the book...apparently whoever is behind this is putting it in their own words now. The author states in
the foreward that not everything there is his, and specifically says this one is not, so it's no surprise he doesn't mention precipitate. Had the OP
quoted instead of leaving a link which no one read, it would have been obvious that the reaction was not performed correctly.
I'd think that directions for the monoethyl diester would also work for the diethyl if repeated (after removing solvent), keeping in mind that some
adjustment should be made, since it would have been optimized for producing as little diethyl diester as possible.
The reason why I brought up the original text is because of how it begins (not in the link): "The essential requirement in the preparation of
diethylmalonic ester and "veronal" is that all reagents must be absolutely anhydrous, otherwise the yields will be vanishingly small. All reagents and
solutions must therefore be protected from the moisture of the air after drying." |