Organic compounds
CA 1292735 C · Owner: Sandoz Ltd. · Inventors: Pedrazzi, Reinhard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A compound which in one of the possible tautomeric forms corresponds to formula I, or a salt thereof in which the sulphonic acid groups are in the 5,7- or 6,8-positions of the naphthyl radical R1 is hydrogen, chlorine, methyl, methoxy -NHCOCH3 or -NHCONH2, R2 is, hydrogen, methyl or methoxy and R3 is -NHCN or -NHCONH2, or a, mixture of compounds of formula I each of which being in free acid or salt form. The compound is useful as a direct dye as such or in the form of dyeing preparations.
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
- Granted December 3, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 3, 2008.
- 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.