Double Bond Between Ring Members Of The Lactone Ring Or Chalcogen Double Bonded Directly At The 3- Or 4-position Of The Lactone Ring (e.g., Ascorbic Acid, Etc.) Patents (Class 549/315)
Amine addition salts (Class 549/316)
Sulfur or -c(=x)-, wherein x is chalcogen, bonded directly to acyclic chalcogen (Class 549/317)
  • Preparation of diacetoneketogulonic acid by oxidation of diacetonesorbose
    Patent number: 4387245
    Abstract: A process for preparing diacetoneketogulonic acid comprises oxidizing diacetonesorbose in two or more oxidizing steps using different oxidizing agents in each step. In preferred embodiments the first oxidation is done electrochemically or using air and the second oxidation is via hypochlorite treatment.
    Type: Grant
    Filed: May 20, 1981
    Date of Patent: June 7, 1983
    Assignee: Merck Patent Gesellschaft Mit Beschrankter Haftung
    Inventors: Rolf Wittmann, Willi Wintermeyer, Jurgen Butzke
  • Derivatives of L-ascorbic acid and D-erythorbic acid
    Patent number: 4368330
    Abstract: 5,6-Anhydro-L-ascorbic acid, 5,6-anhydro-D-erythorbic acid and salts thereof are disclosed. Such compounds are useful intermediates in the preparation of 6-deoxy-6-substituted-L-ascorbic acid and 6-deoxy-6-substituted-D-erythorbic acid, which are useful as antioxidants. Novel 6-deoxy-6-substituted-L-ascorbic and -D-erythorbic acid derivatives are also disclosed.
    Type: Grant
    Filed: April 30, 1981
    Date of Patent: January 11, 1983
    Assignee: Pfizer Inc.
    Inventor: Glenn C. Andrews
  • 5-Keto-L-ascorbic acid-5,5-dimethyl ketal, derivatives thereof and its use as an antioxidant and intermediate
    Patent number: 4342695
    Abstract: 5-Keto-L-ascorbic acid-5,5-dimethyl ketal, alkali metal and alkaline earth metal salts thereof; process for the preparation thereof; its use as an antioxidant and intermediate for production of 5-keto-L-ascorbic acid and L-ascorbic acid. 5-keto-L-ascorbic acid and its 5,5-dimethyl ketal exhibit antiscorbutic activity.
    Type: Grant
    Filed: February 9, 1981
    Date of Patent: August 3, 1982
    Assignee: Pfizer Inc.
    Inventor: Glenn C. Andrews
  • Reduction of 2,5-diketogluconic acid
    Patent number: 4337350
    Abstract: The novel stereoselective and regioselective alkali metal borohydride reduction of 2,5-diketogluconic acid, alkyl esters or salts thereof to form 2-ketogulonic acid together with lesser amounts of 2-ketogluconic acid is disclosed. The 2-ketogulonic acid is readily converted to ascorbic acid.
    Type: Grant
    Filed: April 25, 1980
    Date of Patent: June 29, 1982
    Assignee: Pfizer Inc.
    Inventor: Glenn C. Andrews