Abstract
The diacylaminoquinazolinones are highly selective acylating agents for primary amines in the presence of secondary amines. The chemoselective N-acetylation reagents have been investigated using 2-substituted N,N-diacylaminoquinazolinones (DAQs) and 2-substitued-N-diacylanilines (DAAs). Determination of the selectivity ratios have been made by comparison of the crude product in each case with authentic samples of the amide products using NMR spectroscopy. The control experiments in which pairs of amines compete for acetyl chloride show some selectivity but not comparable with that of DAQs and DAAs selectivity. When the DAQs, DAAs and acetyl chloride react with mixtures of pyrrolidine and piperidine, they give amides in the corresponding ratios. The DAQs 1 and 2 react entirely with diethylamine without any competitive reaction with diphenylamine. The high level of chemoselectivity has also been observed when the 1 and 2 react exclusively with the ethanolamine without any competitive reaction with diethanolamine. Moreover, 1 and 2 react with succinimide without any competitive reaction with phthalimide.