A PHP Error was encountered

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

Straightforward and highly efficient catalyst-free one-step synthesis of 2-(purin-6-yl)acetoacetic acid ethyl esters, (purin-6-yl)acetates, and 6-methylpurines through S(N)Ar-based reactions of 6-halopurines with ethyl acetoacetate. | LitMetric

A novel approach to the synthesis of purines bearing functionalized carbon substituents or methyl in position 6 was developed. Under different reaction conditions, 6-halopurine derivatives could react with ethyl acetoacetate efficiently to yield 2-(purin-6-yl)acetoacetic acid ethyl esters, (purin-6-yl)acetates and 6-methylpurines respectively. No metal catalyst and ligand were required.

Download full-text PDF

Source
http://dx.doi.org/10.1021/ol9002256DOI Listing

Publication Analysis

Top Keywords

2-purin-6-ylacetoacetic acid
8
acid ethyl
8
ethyl esters
8
esters purin-6-ylacetates
8
purin-6-ylacetates 6-methylpurines
8
ethyl acetoacetate
8
straightforward highly
4
highly efficient
4
efficient catalyst-free
4
catalyst-free one-step
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!