Preparation of carbonic anhydrase inhibitors
CA 2114877 C · Owner: Sproull, Steven J. · Inventors: Sproull, Steven J.; Dantanarayana, Anura P.; Conrow, Raymond E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Preparation of Carbonic Anhydrase Inhibitors Abstract of the Disclosure, Carbonic anhydrase inhibitors useful in the control, of ocular hypertension and having the formula:, wherein: Rl and R2 are both chosen from H or C1-4 alkyl; R3 = C1-6 alkyl or CH2(CH2)nOR4 where R4=CH3 or (CH2)nCH3 and n = 1-4; or (CH2)nAr where Ar = unsubstituted phenyl, 3-, I methoxyphenyl or 4-methoxyphenyl and n = 1 or, 2. are prepared by displacing the C(2)-chloro of 3-acetyl- 2,5-dichlorothiophene with benzyl mercaptide to form the thioether of structure, which is then converted to 3acetyl-5-chloro-2-thiophenesulfonamide by reaction with chlorine to form 3-acetyl-5-chloro-2-thiophenesulfenyl chloride, followed …
Read the whole patent
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 February 3, 1994 and granted November 10, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 3, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 3, 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.