Gould-Jacobs Reaction of 5- and 6-Amino-2-substitutedBenzoxazoles. III. Reaction with 3-Ethoxy-2-cyanopropenonitrile and Ethyl 3-Ethoxy-2-cyanopropenoate

Nucleophilic reaction of 5-amino- ( 1 ) and 6-amino-2-substituted benzoxazoles ( 2 ) with 3-ethoxy-2-cyanopropenonitrile ( 3 ) afforded the respective benzoxazolylaminomethylenemalononitriles 5 and 6 . The amino derivatives 1 and 2 reacted with ethyl 3-ethoxy-2-cyanopropenoate ( 4 ) to give the corresponding esters of benzoxazolylamino-2-cyanopropenoic acid 7 and 8 , respectively. The products 7 on thermal cyclization at 250-260 °C in a mixture of diphenyl ether and biphenyl afforded a mixture of angularly and linearly annelated 5-nitrile-4-oxooxazolo[4,5- f ]quinoline 9 and 7-nitrile-8-oxooxazolo[5,4- g ]quinoline 10 ; under the same conditions compounds 8 were converted into 8-nitrile-9-oxooxazolo[5,4- f ]quinolines 11 and 6-nitrile-5-oxooxazolo[4,5- g ]quinolines 12 .