(cyclohex-2-en-1-ylideneamino)urea

7-羟基-3，4-二氢苯并吡喃

1-苯并呋喃-3,6-二醇

2,4-二羟基苯基乙醛酸乙酯

2-(2,4-dihydroxyphenyl)-2-oxoacetic acid