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Expired Canadian patentCanada

Process for the preparation of 9(11)-dehydro steroids

CA 1294952 C · Owner: Marx, Arthur Friedrich · Inventors: Marx, Arthur Friedrich; Barendse, Nicolaas Cornelis Maria Emanuel; Batist, Jacobus Nicolaas Maria

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Abstract From the Canadian patent

9(11)-dehydroandrostanes and 9(11)-dehydropregnanes are prepared by dehydrating the corresponding 9-alpha-hydroxy steroid in the presence of a Lewis acid. The corresponding 8(9)-dehydro-isomer was not detectable. The resulting products are valuable intermediates in steroid synthesis especially in the preparation of corticosteroids.

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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 January 28, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 28, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 13, 1988
GrantedJanuary 28, 1992
Term endedJanuary 28, 2009
Patent numberCA 1294952 C
Classification (IPC)C07J1/00 +2 more

Timeline

Timeline From CIPO dates

1989199219951998200120042007Application filedJune 13, 1988Patent grantedJan 28, 1992Term endedJan 28, 2009

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.