A method of preparing ortho esters
CA 2124522 C · Owner: Bitler, George W. · Inventors: John, Thomas V.; Bitler, George W.; Colvin, David
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Ortho esters of the structure, wherein R1 and R2 are different or the same alkyl moieties and can be a saturated, unsaturated, branched unbranched or, cyclic alkyl moiety of 1-3 carbon atoms are prepared by first, anhydrously reacting hydrogen cyanide or a hydrogen cyanide derivative with a secondary alkanol and hydrogen chloride in the presence of an inert organic solvent. Upon the formation of the resulting imino ether hydrochloride more secondary, alkanol is added to form the ortho esters (I).
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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 May 27, 1994 and granted May 25, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 27, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 27, 2016.
- 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.