Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07J—STEROIDS
  • C07J5/00—Normal steroids containing carbon, hydrogen, halogen or oxygen, substituted in position 17 beta by a chain of two carbon atoms, e.g. pregnane and substituted in position 21 by only one singly bound oxygen atom, i.e. only one oxygen bound to position 21 by a single bond
  • C07J5/0046—Normal steroids containing carbon, hydrogen, halogen or oxygen, substituted in position 17 beta by a chain of two carbon atoms, e.g. pregnane and substituted in position 21 by only one singly bound oxygen atom, i.e. only one oxygen bound to position 21 by a single bond substituted in position 17 alfa
  • C07J5/0061—Normal steroids containing carbon, hydrogen, halogen or oxygen, substituted in position 17 beta by a chain of two carbon atoms, e.g. pregnane and substituted in position 21 by only one singly bound oxygen atom, i.e. only one oxygen bound to position 21 by a single bond substituted in position 17 alfa substituted in position 16
  • C07J5/0069—Normal steroids containing carbon, hydrogen, halogen or oxygen, substituted in position 17 beta by a chain of two carbon atoms, e.g. pregnane and substituted in position 21 by only one singly bound oxygen atom, i.e. only one oxygen bound to position 21 by a single bond substituted in position 17 alfa substituted in position 16 by a saturated or unsaturated hydrocarbon group
  • C07J5/0076—Normal steroids containing carbon, hydrogen, halogen or oxygen, substituted in position 17 beta by a chain of two carbon atoms, e.g. pregnane and substituted in position 21 by only one singly bound oxygen atom, i.e. only one oxygen bound to position 21 by a single bond substituted in position 17 alfa substituted in position 16 by a saturated or unsaturated hydrocarbon group by an alkyl group
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P29/00—Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07J—STEROIDS
  • C07J3/00—Normal steroids containing carbon, hydrogen, halogen or oxygen, substituted in position 17 beta by one carbon atom
  • C07J3/005—Normal steroids containing carbon, hydrogen, halogen or oxygen, substituted in position 17 beta by one carbon atom the carbon atom being part of a carboxylic function
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07J—STEROIDS
  • C07J71/00—Steroids in which the cyclopenta(a)hydrophenanthrene skeleton is condensed with a heterocyclic ring
  • C07J71/0005—Oxygen-containing hetero ring
  • C07J71/001—Oxiranes
  • C07J71/0015—Oxiranes at position 9(11)
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/55—Design of synthesis routes, e.g. reducing the use of auxiliary or protecting groups

Definitions

• This invention relates to a process for preparing flumethasone, flumethasone 21-acetate and its 17-carboxyl androsten analogue, and to certain starting materials for the process.
• Flumethasone, 6a,9a-difluoiO-16a-methylprednisolone was described for the first time in 1962. Although this corticosteroid has an enhanced anti-inflammatory activity, it has not been widely used clinically. At the present time, its economical preparation on an industrial scale is ever more important because it is also an excellent starting material for the production of new difluoro- 17-carboxyl androstenes, which are becoming increasingly important from a clinical point of view.
• Flumethasone and its production are the subject of a number of patents including US 3,499,016 (1962) and British Patent 902,292 (1970).
• the new synthetic techniques developed since 1970 naturally permit a more efficient production of flumethasone with considerably increased yields compared to those obtained with the initial patents.
• European Patent 0 610 138 131 (1994) describes a synthetic route for the preparation of the so called "hydroxyacid".
• the present invention represents considerable unexpected advantages in relation to this prior process patent, namely: the reaction sequence is reduced by one reaction step and by the elimination of the desolvatation step of 6a,9a-difluoro-ll ⁇ ,17a-dihydroxy 16a-methyl 17B- methoxycarbonyl androsta-l,4-diene-3-one, an additional production step, the present process avoids the use of a highly toxic reagent, dimethyl sulphate, permits the simultaneous deacetylation and degradative oxidation of the pregnane side chain forming directly the equivalent androstan derivative, increased yield of the hydroxyacid with excellent purity.
• reaction sequence of EP 0 610 138 131 transforms the common starting material of both processes as from the first step into the androstane series.
• the invention also provides compounds of the formula (V):
• X is hydrogen or fluorine
• step (d) of the process the flumethasone 21-acetate formed has the formula:
• the present invention permits the direct transformation of flumethasone acetate into compound I.
• the two new compounds III a) and III b) are depicted as a general formula (N) in claim 8.
• the compound I can also be obtained as described in US Patent 3,636,010 by oxidizing flumethasone free alcohol.
• the starting material of the present process is commercially available and widely used in the preparation of corticosteroids such as dexamethasone and icomethasone.
• the 3-keto group is enolised by carboxylic acid chloride, forming an enolic ester residue of the formula -COR in which R is an aryl or aralkyl group.
• the preferred compound for the enolisation is benzoyl chloride, yielding the compound of formula III a) in the presence of a tertiary amine, such as pyridine.
• the preferred solvent is ⁇ , ⁇ 'dimethylacetamide and the reaction is preferably carried out at a temperature of 80 to 85°C, yielding the ? 3,5 enol benzoate.
• the compound III a) is reacted with an electrophilic fluorination agent to yield the corresponding 6 fluoro derivative.
• the preferred fluorination agent is the l-chloromethyl-4-fluoro-l,4-diazoniabicyclo [2.2.2]octane bis(tetrafluoroborate), Selectfluor ® .
• the preferred solvent is acetonitrile in presence of water at a preferred temperature of -5°C ⁇ 2°C.
• the 3 enolic ester can be easily transfo ⁇ ned into the system of 3-keto- 1,4-diene yielding the compound IN.
• the elimination of the enolic ester is preferably effected by an aqueous solution of sodium metabisulf ⁇ te and ammonia.
• a 9,11-epoxy group of compound IN is reacted with a concentrated aqueous solution of hydrofluoric acid or with a solution of hydrogen fluoride in ⁇ , ⁇ 'dimethylformamide by per se known processes at a temperature below 25°C.
• the reaction mixture is poured into a mixture of ice and ammonia sufficient to neutralise the hydrofluoric acid and precipitate simultaneously the flumethasone 21-acetate with a high yield and purity.
• the product obtained can be recrystallized for instance from methanol.
• the 21-acetate obtained can be subsequently hydrolyzed by any of the known processes yielding flumethasone free alcohol.
• One of the preferred processes is effected in degassed methanolic potassium hydroxide at a temperature between -15°C and -5°C.
• the end of the reaction is ascertained by HPLC after one hour and it is considered complete when the amount of starting compound is less than 1 %.
• flumethasone is suspended in tetrahydrofuran and a solution of the oxidation agent is added dropwise.
• the substrate first starts to dissolve followed by precipitation.
• the oxidation is performed preferably at 20°C employing, for example, periodic acid.
• completion of the reaction is controlled by HPLC. Once the amount of non reacted flumethasone is less than to 0.3%, the reaction is considered complete.
• the reaction mixture containing compound I is precipitated by adding to an aqueous solution of sodium metabisulfite and ice.
• flumethasone 21-acetate can be simultaneously deacetylated and oxidised by methanolic potassium hydroxide and aqueous hydrogen peroxide yielding, after completion of the reaction, the desired hydroxyacid, compound 1, by acidifying the reaction mixture with diluted hydrochloric acid to pH 2. This reaction is performed at 10°C, ⁇ 2°C with agitation until the reaction is complete.
• the cumulative stoichiometric yield of the process described in EP 0610138 Bl so as to obtain unrecrystallized compound I is 48.9% as from 9,l lB-epoxy-17a,21- dihydroxy-pregna-l,4-diene-3,20-dione, whilst according to the present process the cumulative stoichiometric yield obtained is 62.4%, as per Examples 1 b), 2 and 4, as from the 21-acetate of the above starting material.
• the reaction mixture is poured into a solution of 100 ml water, 1.2 g of sodium metabisulfite, 5 ml of ammonia 25% and 200 ml of dichloromethane.
• the pH of the solution is adjusted to between 7-8 and is stirred for 30 minutes after which the phases are separated and the organic phase is washed with ammonia 12.5%.
• the organic phase is evaporated in vacuum until dryness and substituted by methanol.
• the desired compound crystallizes, is then filtered and dried at 40 to 45°C, yielding 40 g of the title product with a purity by HPLC of 90%, in area.
• Example 1 36 g of the compound obtained in Example 1 is dissolved in an inert atmosphere in 360 ml of a complex of hydrogen fluoride and dimethylformamide (-64% w/w) at a temperature of 20°C ⁇ 3°. After stirring for three hours at this temperature, it is poured, under agitation, into a mixture of 3,000ml of water, 1,000ml of ice and 800 ml of ammonia 25% maintaining the temperature below 25°C during the whole precipitation.
• a complex of hydrogen fluoride and dimethylformamide 64% w/w

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• Organic Chemistry (AREA)
• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Public Health (AREA)
• Medicinal Chemistry (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Pharmacology & Pharmacy (AREA)
• Rheumatology (AREA)
• Animal Behavior & Ethology (AREA)
• Pain & Pain Management (AREA)
• General Chemical & Material Sciences (AREA)
• Veterinary Medicine (AREA)
• Steroid Compounds (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Anti-Oxidant Or Stabilizer Compositions (AREA)
• Control Of Combustion (AREA)
• Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
• Oscillators With Electromechanical Resonators (AREA)

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Citations (4)

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• 2001
  • 2001-06-12 PT PT102628A patent/PT102628B/pt active IP Right Grant
• 2002
  • 2002-06-06 US US10/162,862 patent/US6528666B1/en not_active Expired - Lifetime
  • 2002-06-11 EP EP02735607A patent/EP1395603B1/en not_active Expired - Lifetime
  • 2002-06-11 ES ES02735607T patent/ES2338768T3/es not_active Expired - Lifetime
  • 2002-06-11 PL PL367843A patent/PL206731B1/pl unknown
  • 2002-06-11 CA CA002450661A patent/CA2450661C/en not_active Expired - Fee Related
  • 2002-06-11 AU AU2002310616A patent/AU2002310616B2/en not_active Ceased
  • 2002-06-11 WO PCT/GB2002/002644 patent/WO2002100878A1/en active IP Right Grant
  • 2002-06-11 DK DK02735607.0T patent/DK1395603T3/da active
  • 2002-06-11 CN CNB028117662A patent/CN1244593C/zh not_active Expired - Fee Related
  • 2002-06-11 AT AT02735607T patent/ATE460422T1/de active
  • 2002-06-11 IL IL15934302A patent/IL159343A0/xx unknown
  • 2002-06-11 JP JP2003503644A patent/JP4095018B2/ja not_active Expired - Fee Related
  • 2002-06-11 DE DE60235625T patent/DE60235625D1/de not_active Expired - Lifetime
  • 2002-06-11 NZ NZ530536A patent/NZ530536A/en not_active IP Right Cessation
  • 2002-06-11 RU RU2004100309/04A patent/RU2260596C1/ru not_active IP Right Cessation
• 2003
  • 2003-12-11 NO NO20035517A patent/NO326153B1/no not_active IP Right Cessation
  • 2003-12-11 IL IL159343A patent/IL159343A/en not_active IP Right Cessation
  • 2003-12-12 ZA ZA200309656A patent/ZA200309656B/xx unknown
• 2010
  • 2010-04-07 CY CY20101100318T patent/CY1109960T1/el unknown

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