329729-34-2Relevant articles and documents
Stereoisomerism in 3-[N-(2-acetoxypropanoyl)-N-acylamino]-quinazolin-4(3H)-ones, enantioselective acylating agents
Al-Schemi, Abdullah G.,Atkinson, Robert S.,Fawcett, John,Russell, David R.
, p. 4413 - 4421 (2000)
The title compounds diacylaminoquinazolinones (DAQs) are enantioselective acylation agents for amines and a detailed study of their stereostructures was undertaken with the aim of understanding how this enantioselectivity arises. The N-N bond in these DAQs is a chiral axis. Even where both N-acyl groups are (S)-2-acetoxypropanoyl, the N-N bond is still a chiral axis because in the most stable conformation of the planar imide moiety, one exolendo orientation of the carbonyl groups is much preferred over the alternative (endolexo) as revealed by NMR spectroscopy. A conformational preference within the 2-acetoxypropanoyl grouping accounts for the presence of a single exolendo conformation in solution for some of these DAQs (see above) but an interconverting exolendo? endolexo mixture for others. Where a single exolendo conformation is present in solution, evidence is presented that this closely resembles the X-ray determined crystal structure. A mechanism for the second acylation step to form these DAQs is proposed, which involves preliminary O-acylation of the 3-(monoacylamino)quinazolinone. The Royal Society of Chemistry 2000.
