Preparation of mixed trialkyl alkylcarbonate derivatives of etidronic acid via an unusual route

A method to prepare four (3a–d) trialkyl alkylcarbonate esters of etidronate from P,P'-dimethyl etidronate and alkyl chloroformate was developed by utilizing unexpected demethylation and decarboxylation reactions. The reaction with the sterically more hindered isobutyl chloroformate at a lower...

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Bibliographic Details
Main Authors: Petri A. Turhanen, Janne Weisell, Jouko J. Vepsäläinen
Format: Article
Language:English
Published: Beilstein-Institut 2012-11-01
Series:Beilstein Journal of Organic Chemistry
Subjects:
Online Access:https://doi.org/10.3762/bjoc.8.228
Description
Summary:A method to prepare four (3a–d) trialkyl alkylcarbonate esters of etidronate from P,P'-dimethyl etidronate and alkyl chloroformate was developed by utilizing unexpected demethylation and decarboxylation reactions. The reaction with the sterically more hindered isobutyl chloroformate at a lower temperature (90 °C) produced the P,P'-diester (2) as a stable intermediate product. A possible reaction mechanism is discussed to explain these methyl substitutions. These unusual reactions also clarify why it is difficult to prepare alkylcarbonate prodrugs from bisphosphonates. The compounds prepared were analysed by spectroscopic techniques.
ISSN:1860-5397