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The zwitterions underwent facile isomerization by N - terminal ammonium proton migration to the thioenol anion - radical group forming aminothioketyl intermediates .
 Chemical: N; Chemical: ammonium; Chemical: thioenol anion - radical; Chemical: aminothioketyl
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: N; Chemical: ammonium; Chemical: thioenol anion - radical; Chemical: aminothioketyl