Back to results
US 2004/0171870 A1Published application
Process for preparing methylene biosphosphonic and salts
AssigneeAstraZeneca UK Limited, a London corporation
InventorMark Purdie
Life of this patent
Estimating the term…
Abstract
A process for the preparation of salts of substituted or unsubstituted methylene bisphosphonic acids by hydrolysing the corresponding acid ester with hydrochloric acid, removing water from the acid azeotropically prior to addition of an amine or a base to produce the resultant salt in good yield.
Claims19
A process for preparing salts of a substituted or unsubstituted methylene bisphosphonic acid of general formula I
- 4
- wherein X1 and X2 are independently hydrogen or halogen, which process comprises hydrolysing, using hydrochloric acid, the corresponding ester of formula II,
- 5
- wherein X1 and X2 are defined above and R is a C1-4 straight or branched chain alkyl group and converting the acid to a salt by reaction with a base characterised in that the concentration of hydrochloric acid is from 15% to 20% by weight and water is removed azeotropically from the resultant acid using n-butanol prior to the addition of an amine or a base.
1 more element
A salt of substituted or unsubstituted methylene bisphosphonic acid of formula I
- 6
- wherein X1 and X2 are independently hydrogen or halogen.
Dependencies are inferred from the claim text.