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US 5,688,983 AGranted
Process for the preparation of tetraethyl methylenebisphosphonate
AssigneeZeneca Limited
InventorsMichael R. Leadbetter, Richard W. Brown, Maureen M. McKenna
Life of this patent
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Abstract
This invention relates to a process for the preparation of tetraethyl methylenebisphosphonate by the reaction of dichloromethane with diethyl phosphite, wherein the reaction is performed in a polar aprotic solvent or mixtures thereof.
Claims13
A process for preparing a compound of formula (I) ##STR5## comprising:
- reacting a compound of the formula (II) ##STR6## wherein M is selected from the group consisting of alkali metals, alkaline earth metals and hydrogen, with dichloromethane in the presence of at least one polar aprotic solvent other than dichloromethane.
A process for preparing a compound of formula (I) ##STR7## comprising the steps of:
- a) reacting diethylphosphite with a base to form a compound of formula (II) ##STR8## wherein M is selected from the group consisting of an alkali metal, an alkaline earth metal and hydrogen;
- and
- b) reacting dichloromethane with said compound of formula II in the presence of a polar aprotic solvent or mixtures thereof other than dichloromethane.
Dependencies are inferred from the claim text.