Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D313/00—Heterocyclic compounds containing rings of more than six members having one oxygen atom as the only ring hetero atom
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
  • H03F1/02—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
  • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
  • H03F3/24—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers of transmitter output stages

Definitions

• Zearalenone is catalytically reduced with hydrogen for a time suflicient to reduce the zearalenone to zearalanol in the presence of a platinum catalyst and a weak acid having a first acid ionization constant of from about 1X10 to X in water at about 25 C. and said acid not being itself reduced under the conditions of the zearalenone reduction.
• This invention relates to a method for reducing zearalenone to a mixture of the highand low-melting point diastereoisomers of zearalanol.
• zearalenone and zearalanol conform with the nomenclature in an article in Tetrahedron Letters, Pergamon Press, Ltd., No. 27, pp. 3109-3114 (1966).
• zearalenone having the formula is converted to zearalanol, having the formula r n)a (CHM by reduction of the olefinic bond and the ketone group in the presence of hydrogen, a mixture of diastereoisomers of zearalanol is formed.
• This reduction carried out in the presence of a Raney nickel catalyst, is disclosed in U.S. Pat. No. 3,239,345.
• the diastereoisomers differ in melting point.
• the disclosed reduction provides an approximately 55:45 ratio of the high-melting point to the lowmelting point diastereoisomer.
• certain weak acids may be employed in a process for the catalytic reduction of zearalenone to a mixture containing a major amount, e.g., greater than weight percent, for example, about weight percent or more, of the diastereoisomer of zearalanol having the higher melting point and a minor amount, e.g., less than 45 weight percent, for example, about 40 weight percent or less, of the diasteroisomer of zearalanol having the lower melting point.
• a major amount e.g., greater than weight percent, for example, about weight percent or more
• zearalanol having the higher melting point e.g., about weight percent or more
• a minor amount e.g., less than 45 weight percent, for example, about 40 weight percent or less
• the reduction of zearalenone is conducted in the presence of a solvent, a platinum catalyst, and certain weak acids for a time sufiicient to reduce the zearalenone to zearalanol and provide a high ratio of the high melting point diastereoisomer to the low melting point diastereoisomer.
• the product will generally contain a major amount of the high melting point diastereoisomer of zearalanol.
• the weak acid employed in the process of the present invention has a first acid ionization constant of from about 1X10- preferably 5X10- to 5 X 10- in an aqueous solution at 25 C., and will not itself be reduced to a weaker acid under the conditions employed for the zearalenone reduction.
• weak acid refers to acids which are less than essentially completely ionized in water (except in extremely dilute solution). It conforms with standard nomenclature as found in, for example, Fundamental Concepts of Chemistry, Appleton-Century-Crofts (1969), pp. 233 and 234. Such weak acids include weak acids as well as moderately strong acids. Exemplary of the weak acids which may be employed in the present invention are citric acid, tartaric acid, phosphoric acid, and oxalic acid.
• the zearalenone can be prepared and purified as described in Examples II and III of U.S. Pat. No. 3,239,345.
• the zearalenone is advantageously suspended or dissolved in a suitable solvent, preferably a lower alkanol, e.g., ethanol, normal propyl alcohol, isopropyl alcohol and the I like, preferably those containing from 1 to 3 carbon atoms and particularly ethanol.
• zearalanol-producing amounts of a weak acid often a small amount, e.g., about 0.001 to 5 volume percent (based on the solvent), preferably from about 0.01 to 3 volume percent or equivalent weight, of weak acid is added to the solvent.
• the reaction may be conducted in the presence of, for instance, about 2 to 10 volume percent of water.
• the zearalenone and solvent can advantageously be present in amounts of, for example, from about 1 to 25 grams of zearalenone per cc. of the solvent.
• a platinum catalyst supported on a suitable carrier, e.g., charcoal, is advantageously used.
• the catalyst contains from about 0.01 to about 10 weight percent of platinum and is employed in catalytic amounts, generally a catalyst to zearalenone weight ratio of from about 0.00l:1 to 1:1.
• the zearalenone is reduced in the presence of hydrogen under reducing conditions for a time suflicient to reduce substantially all of the zearalenone.
• the reduction can be carried out at a temperature of from about 15 to 100 C., preferably about 20 to 60 C. with a hydrogen pressure generally of from about 20 to 1000 p.s.i., preferably 25 to 100 p.s.i., for at least 3, preferably about 3 to 8, hours.
• the platinum catalyst is removed from the reaction mixture, e.g., by filtration, andthe resulting'mixture can; as a-matter of convenience, be concentrated, to say, a volume of from about 0.5 to 0.1 of the reaction mixture volume, and filtered again.
• the filtered, concentrated solution can be diisomer of zearalanol comprising catalytically reducing luted with-water, for example, in an amount of from zearalenone with hydrogen under reducing conditions in about 2 to 4 volumes of the concentrated solution, by addthe presence of zearalanol-producing amounts of a weak ing water slowly while stirring the solution.
• said weak solution is advantageously allowed to stand at room temacid having a first acid ionization constant of from about perature for a time suflicient to allow the zearalanol to 1 10 to 5 10- in aqueous solution and said weak precipitate from the solution which can be about 2 to 4 acid not itself being reduced to a weaker acid under the hours or more. Filtration of the mixture yields the white reducing conditions.
• the catalyst is employed in a catalyst to zearalenone weight
• the following examples are presented to further illusratio from about 0.001:1 to 1:1. trate the invention and are not in limitation thereof.
• zearalanol which is analyzed to be about 76% of the hlgh 7
• EXAMPLES H t 1X 8 The method of claim 1 wherein the weak acid has The following examples were conducted in essentially a first acid ionization constant of from about 5 1O to the same procedure as that set forth in Example 1 except 5X 10-1- ditferent solvents and weak acids are employed. The re- 9. The method of claim 2 wherein the weak acid is sults of these examples are set forth in Table I. 40 tartaric acid.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Priority Applications (16)

Applications Claiming Priority (1)

Publications (1)

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Cited By (1)

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• 1972
  • 1972-09-26 US US00292449A patent/US3808233A/en not_active Expired - Lifetime
• 1973
  • 1973-06-05 DE DE2328605A patent/DE2328605C2/de not_active Expired
  • 1973-06-06 CA CA173,325A patent/CA980785A/en not_active Expired
  • 1973-06-12 AT AT511973A patent/AT330377B/de not_active IP Right Cessation
  • 1973-06-26 ZA ZA734356A patent/ZA734356B/xx unknown
  • 1973-06-28 IL IL42623A patent/IL42623A/en unknown
  • 1973-06-29 AU AU57512/73A patent/AU475426B2/en not_active Expired
  • 1973-07-02 GB GB3149073A patent/GB1379859A/en not_active Expired
  • 1973-07-05 CH CH978473A patent/CH587839A5/xx not_active IP Right Cessation
  • 1973-07-10 ES ES417199A patent/ES417199A1/es not_active Expired
  • 1973-07-17 DK DK394573AA patent/DK130464B/da not_active IP Right Cessation
  • 1973-07-18 PH PH14833A patent/PH10914A/en unknown
  • 1973-08-02 SE SE7310661A patent/SE383745B/xx unknown
  • 1973-08-23 NL NL7311613A patent/NL7311613A/xx not_active Application Discontinuation
  • 1973-09-25 BE BE135997A patent/BE805261A/xx not_active IP Right Cessation
  • 1973-09-25 FR FR7334287A patent/FR2200263B1/fr not_active Expired

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