Reactions of 3‐acetyltropolone and its methyl ethers with hydroxylamine. Formation of 8 H ‐cyclohept[ d ]isoxazol‐8‐one and 8 H ‐cyclohept[ c ]isoxazol‐8‐one

The reaction of 3‐acetyltropolone ( 1 ) with hydroxylamine under the acidic condition gave 3‐methyl‐8 H ‐cyclohept[ d ]isoxazol‐8‐one ( 4 ) and its oxime ( 5 ), and under the neutral condition gave 4 and 3‐acetyltropolone oxime ( 6 ). The reaction of 3‐acetyl‐2‐methoxytropone ( 2a ) with hydroxylamine under the acidic condition gave 4, 5 , and 4‐methyl‐1 H ‐2,3‐benzoxazin‐1‐one ( 7 ), and under the neutral condition gave 4, 7 , 3‐methyl‐8 H ‐cyclohept[ c ]isoxazol‐8‐one ( 8 ), and its oxime ( 9 ). The reaction of 7‐acetyl‐2‐methoxytropone ( 2b ) with hydroxylamine under the acidic condition gave 4 and 5 , and under the neutral condition gave 5, 7 , and 9 .