27213
Subsequent addition of hydride donors , for 30 min , followed by acid hydrolysis of the mixture allowed detection and quantification of 6 - ( 2 - { 2 - [ ( 9H - purin - 6 - yl ) amino ] ethoxy } ethoxy ) - 9H - purin - 2 - amine , the reduced cross - link formed from deposition , via the diazonium ion , of a 3 - oxapentanal fragment on O ( 6 ) - Gua , and condensation with N ( 6 ) - Ade , presumably in the vicinity .
 hydride, 6 - ( 2 - { 2 - [ ( 9H - purin - 6 - yl ) amino ] ethoxy } ethoxy ) - 9H - purin - 2 - amine, diazonium, 3 - oxapentanal, O, Gua, N, Ade
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 hydride, 6 - ( 2 - { 2 - [ ( 9H - purin - 6 - yl ) amino ] ethoxy } ethoxy ) - 9H - purin - 2 - amine, diazonium, 3 - oxapentanal, O, Gua, N, Ade