The synthesis of 3-[(dimethylamino)(2-phenyl-5-oxo-2-oxazolinylidene-4)methyl]imidazo[1,2-x]azines and related compounds, intermediates in the formation of azaaplysinopsin derivatives

4-(2-Bromo-1-dimethylaminoethylidene)-2-phenyl-5(4H)-oxazolone (5) reacts with N,N-dimethyl-N'-heteroarylformamidines 7 to form imidazoazine derivatives 9 with the oxazolone ring connected through a conjugated double bond to the fused imidazole system at position 3. Compounds 9 were transformed with sodium methoxide in methanol into 2-benzoylamino-3-dimethylamino-3-imidazoazinylpropenoates 10, while by treatment with hydrochloric acid in methanol, 3-(benzoylaminoacetyl)imidazoazines 12 were formed. The synthesis of compounds 9 represents a facile route to intermediates in the synthesis of aza-aplysinopsin and related systems.