18390
With regard to structure - activity relationship ( SAR ) trends among the various substituents on the pyridyl ring , relatively small and nonbasic substituents were preferable to sterically demanding or basic substituents .
 Chemical: pyridyl
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: pyridyl 
Answer:
 Chemical: pyridyl