Rifamycin derivatives and processes for the manufacture thereof
CA 2032672 A1 · Owner: Chen, Jen · Inventors: Francis, John E.; Veenstra, Siem J.; Chen, Jen
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Rifamycin derivatives and processes for the manufacture thereof Abstract, Described are novel acyl derivatives of rifamycins of the formula (I), and the salts thereof, in which the structural elements -A1-A2- -A3-A4- and -A5-A6- each, denote ethylene or vinylene or the elements -A1-A2- and -A3-A4- each denote ethylene and -A5-A6- denotes vinylene; X represents or , and R6 denotes, hydrogen or alkyl; alk denotes an aliphatic hydrocarbon radical; R1 denotes hydrogen or acyl; R2 denotes alkyl which is optionally substituted by an aromatic radical and R3 and, R3' represent a common bond or R3 denotes hydrogen or acyl, and R3' is hydrogen; R4 denotes hydrogen, cycloalkyl or aryl; R5 denotes …
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 December 19, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 19, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 19, 2012.
- 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.