22019
Reaction of 17 alpha - bromo - 21 - iodo - 3 beta - acetoxypregn - 5 - en - 20 - one with either ( L ) - serine methyl ester , or ( D ) - serine methyl ester resulted in methyl N - [ 3 beta - acetoxy - 21 - oxopregna - 5 , 17 ( 20 ) - dien - 21 - yl ] - ( L ) - serinate and methyl N - [ 3 beta - acetoxy - 21 - oxopregna - 5 , 17 ( 20 ) - dien - 21 - yl ] - ( D ) - serinate ( as mixtures of related [ 17 ( 20 ) E ] - and [ 17 ( 20 ) Z ] - isomers ) .
 Chemical: 17 alpha - bromo - 21 - iodo - 3 beta - acetoxypregn - 5 - en - 20 - one; Chemical: ( L ) - serine methyl ester; Chemical: ( D ) - serine methyl ester; Chemical: methyl N - [ 3 beta - acetoxy - 21 - oxopregna - 5 , 17 ( 20 ) - dien - 21 - yl ] - ( L ) - serinate; Chemical: methyl N - [ 3 beta - acetoxy - 21 - oxopregna - 5 , 17 ( 20 ) - dien - 21 - yl ] - ( D ) - serinate
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: 17 alpha - bromo - 21 - iodo - 3 beta - acetoxypregn - 5 - en - 20 - one, ( L ) - serine methyl ester, ( D ) - serine methyl ester, methyl N - [ 3 beta - acetoxy - 21 - oxopregna - 5 , 17 ( 20 ) - dien - 21 - yl ] - ( L ) - serinate, methyl N - [ 3 beta - acetoxy - 21 - oxopregna - 5 , 17 ( 20 ) - dien - 21 - yl ] - ( D ) - serinate 
Answer:
 Chemical: 17 alpha - bromo - 21 - iodo - 3 beta - acetoxypregn - 5 - en - 20 - one; Chemical: ( L ) - serine methyl ester; Chemical: ( D ) - serine methyl ester; Chemical: methyl N - [ 3 beta - acetoxy - 21 - oxopregna - 5 , 17 ( 20 ) - dien - 21 - yl ] - ( L ) - serinate; Chemical: methyl N - [ 3 beta - acetoxy - 21 - oxopregna - 5 , 17 ( 20 ) - dien - 21 - yl ] - ( D ) - serinate