4,5- AND 2,5-ADDITIONS TO OXAZOLES

Article abstract of DOI:10.1016/S0040-4020(01)85135-8

An investigation of the reaction of variously substituted oxazoles 1a-1 with Br2 in methanol revealed the formation of non-aromatic addition products.In general the presence of an aromatic substituent at the 4-position of oxazoles or the presence of a 4-methyl group if the 2-substituent is also aliphatic favors formation of 2,5-dimethoxy-3-oxazolines 3, while an aromatic substituent at the 2-position favors formation of ring-opened amides 2 or 7 or of 4,5-dimethoxy-2-oxazolines 5.Valuable information about intermediates in these reaction can be obtained by following the bromination of 1 in CD3OD by 1H- and 13C-NMR.