Conversion of hydroxymethyl-iminodiacetic acid to phosphonomethyl-iminodiacetic acid
CA 2109269 A1 · Owner: Hampshire Chemical Corp. · Inventors: Cullen, Barry A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for preparing N-phosphonomethyl iminodiacetic acid wherein solutions of an alkali metal salt of IDA are reacted with formaldehyde so as to form the alkali metal salt of hydroxymethyliminodiacetic acid (HMIDA). The HMIDA can be subsequently reacted with a phosphorous source such as phosphorous acid to produce PMIDA in good yield.
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 26, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 26, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 26, 2015.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.