Benzo-1,4-quinones
CA 1235134 A · Owner: Ciba-Geigy Investments Ltd. · Inventors: Howell, Frederick H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
New benzo-1,4-quinones New benzo-1,4-quinones and salts thereof with organic or inorganic acid and bases have the formula I, (I) wherein p is 1 or 2 and q is 0 or 1, provided that p + q is 1 or 2 R is a residue of formula II, (II) , wherein Q is selected from the residues -CO2R4 -CON(R4)(R5), -OR5, -OCOR7, -N(R8)(R9) -PO(OR10)(OxR11), -SO2R12, -CN, Halogen -NO2 or COR13, n is an interger from 1 to 20 k is 1 or 2 and x, is 0 or 1, and R1 to R5 and R7 to R13 have the significance as given in claim 1. The compounds of formula I are useful in photographic materials such as bleaching inhibitors in films of photographic silver dye bleach materials.
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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
- Granted April 12, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 12, 2005.
- 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.