3-phenylaminoisoxazol-5(2h)-ones,s ubstituted on nitrogen with an isoquinoline or quinazoline group, react with tertiary amine bases to give imidazo annelated compounds. when the n-substituent is a nitropyridine, 2-aminoindole derivatives are formed instead. evidence is presented that the reactions proceed by initial addition of the tertiary arnine to c-4