A facile synthesis of 2-[1-(dialkylamino)alkyl]-4H-3,1-benzoxazin-4-ones by the reaction of 1,1-dimethylethyl 2-isocyanobenzoates with N,N-dialkyliminium iodides

A convenient synthetic approach to 2-[1-(dialkylamino)alkyl]-4H-3,1-benzoxazin-4-ones has been developed. Thus, 1,1-dimethylethyl 2-isocyanobenzoates, which can be readily prepared from 2-nitrobenzoic acids by a simple four-step sequence, react with N,N-dialkyliminium iodides without using any catalysts under mild conditions to give the desired products in generally fair-to-good yields.