Beilstein J. Org. Chem.2022,18, 102–109, doi:10.3762/bjoc.18.11
blocks was developed. Regioisomeric methyl 5-(N-Boc-cycloaminyl)-1,2-oxazole-4-carboxylates were prepared by the reaction of β-enaminoketoesters (including azetidine, pyrrolidine or piperidine enamines) with hydroxylamine hydrochloride. Unambiguous structural assignments were based on chiral HPLC
Meldrum’s acid in the presence of EDC·HCl and DMAP, followed by methanolysis of the corresponding adducts [27][28][31][36][37][38]. Reaction of the resulting β-keto esters 2a–h with N,N-dimethylformamide dimethylacetal afforded cycloaminyl β-enaminoketoesters 3a–h. After isolation of compounds 3a–h from
PDF
Graphical Abstract
Figure 1:
Examples of amino-functionalized 1,2-oxazole derivatives I–VIII.