Severity: Warning
Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3122
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
An efficient transition-metal-free oxidative cyclization reaction using isatins and alkynes for the facile synthesis of structurally diverse 4-quinolones has been developed. Intriguingly, switchable access to substituted 3-carboxylate-4-quinolones and 1-vinyl-3-carboxylate-4-quinolones could be achieved by choosing a different base in the reaction. The obtained products could undergo further transformations, increasing the application potential of the method in organic synthesis.
Download full-text PDF |
Source |
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http://dx.doi.org/10.1021/acs.orglett.8b01645 | DOI Listing |
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