25840
We further designed and synthesized 4 - hydroxypyridazin - 3 ( 2H ) - one derivatives , which are equivalent to the 3 - hydroxy - pyridine - 2 ( 1H ) - one series but lack cell toxicity .
 Chemical: 4 - hydroxypyridazin - 3 ( 2H ) - one; Chemical: 3 - hydroxy - pyridine - 2 ( 1H ) - one
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: 4 - hydroxypyridazin - 3 ( 2H ) - one, 3 - hydroxy - pyridine - 2 ( 1H ) - one 
Answer:
 Chemical: 4 - hydroxypyridazin - 3 ( 2H ) - one; Chemical: 3 - hydroxy - pyridine - 2 ( 1H ) - one