• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:

    公开号:SU991947A3
    申请号:SU782627107
    申请日:1978-06-16
    公开日:1983-01-23
    发明作者:Мотт Бреннан Томас；Патрик Брэнегэн Даниэль；Дуглас Викс Пол；Эрнст Кухла Дональд
    申请人:Пфайзер Инкорпорейтед (Фирма)；
    IPC主号:
    专利说明:

    (54) METHOD OF OBTAINING Y - PIRONES The invention relates to an improved method for producing L-pyronium of the general formula H hydrogen atom or benzyl. These compounds, for example maltol and ethyl maltol, are used as flavoring and flavoring additives to food products, as well as ingredients in perfumes and essential oils. A known method for the preparation of 2-meth-Z-oxypyran-4-one (maltol), concluded in the fact that (2Rj 6S) -4-benzoyloxy-2-benzoyloxymethyl-2, 3-dihydro-6-methoxy-2H-pyran- 3-one is treated with an aqueous solution of a strong acid, for example, trifluoroacetic acid, at room temperature, and the resulting 2-benzoyloxymethyl-3 hydroxy-4H-pyran-4-one is subjected to zinc reduction by solous acid when heated. The disadvantage of this method is the two-stage process, in addition, this method can be used to obtain only one compound. The purpose of the invention is to simplify the process, expanding the raw material base and the range of target products. This goal is achieved in the way that the 2H-pyran-3-one derivative of the formula AA ° where H - has the indicated values X - chlorine or bromine atom is processed an aqueous solution of a strong acid at the boiling point of the reaction medium. . The compound of formula I is obtained by dehydration of 4-bromo-4-chloro-6-hydroxy-2H-pyran-3 (6H) -one derivatives, which in turn are obtained by acting on furfuryl alcohol derivatives with two equivalents of a halogen-containing oxidant at a temperature from 0 ° С to the temperature the environment.
    Example 1. 4-Bromo-b-hydroxy-2-methyl-2H-pyran-3 bH-one.
    In a solution consisting of 25 g of 1- (2-furyl) -i-ethanol in 125 ml of tetrahydrofuran and 125 ml of water, 2.2 equivalents of bromine are added dropwise at O-5 ° C. support 5 -. After the addition of bromine, the solution is stirred at room temperature for 30 minutes, and the pH is adjusted to 2.1 with 2N. NaOH solution.
    The reaction mixture was extracted with ethyl acetate (3 x 100 ml). The ethyl acetate extracts are mixed, dried over MgSO4, filtered, and dried. The residue is chromatographed on silica gel and eluted with chloroform-ethyl acetate (95: 5). The resulting product is an orange oil subjected to repeated chromatographic analysis on silica gel and elution with a mixture of choroform-ethyl acetate (95: 5).
    NMR (CDCP, S): 7.3 (lH, d); 5.6 (lH, d) 4.7-5.0 (lH, q); 1.1-1.5 (3N, m).
    Example 2. The method used in Example 1 is repeated and the 4-bromo-b-hydroxy-2-ethyl-2H-pyran-3 (bH) -one is obtained.
    . NMR (CDCP.S): 7.4 (1H, d); 4.6 4, 9 (lH, m); 1.8-2.2 (2H, m) 1.0-1.3 (3H.t) and 4-bromo-6-hydroxy-2H-pyran-3 (eH) -one.
    NMR (CDCF,, 5): 7.4 (lH, d); 4.6 (2H, d from d);
    Example 3 A solution of 4-bromo. 6-hydroxy-2-methyl-2H-pyran-3 (6H) -one is prepared by dissolving this compound in an aqueous solution of an inorganic or organic acid. The solution is then heated under reflux, cooled to room temperature, the pH is adjusted to 2.1 with bn. MaOH, and the reaction mixture is extracted with chloroform. Concentration gives maltol. The acids used, the reaction time, and the maltol yields are given in the table.
    Alternatively, toluene sulfonic acid vapor may be used, and such organic plant exchange resins are used
    the rulers, like benzene and toluene, together Example 4. Repeat the method
    权利要求:
    Claims (1)
    [1]
    with acidic materials, similar to that described in example 1, using chlorine instead of bromine and correspondingly furfuryl alcohols to obtain the following compounds: 4-Chloro-b-hydroxy-2-methyl-2-H-pyran-3 (bN) -he. NMR (CDCEj. S): 7, l (lH, d); 5.8 (lH, d 4.6-5.0 (lH, m; 4.4 (1H, Br, S); 1.2 l, 5 (3H, m). 4-Chloro-b-hydroxy-2-ethyl-2H-pyran-3 (6H) -oH. NMR (Cpc ,, S): 7.0-7, l (lH, d); 5.6-6.0 (2H, m); 4.4-5.0 (lH, m)} 1.6 2, 2 (2H, m); 0.9-l, l (3H , t). 4-Chloro-b-hydroxy-2H-pyran-3 (6H) -OH. NMR (CDCE ,, S): 7.1-7.2 (lHjd); 5.6 (lH, d) : 4.4-4.9 (2H, d from d)% 0, dBavleno. Example 5. The 4-Chloro-6-pxy-2-methyl-2H-pyran-3 (bN) -one is heated under vacuum for 16 hours at 4 ° C. The resulting oily solid is crystallized from isopropyl alcohol to give 6.6-oxy-bis-4-bromo-2-methyl-2H-pyran-3 (6H) -one, having a mp of 125c. Example III b. The method described in Example 5 is repeated, and the following derivatives b, b-oxy-b are obtained. is - 4-hpor-2H-pyran-3 (bN) -one: R. X So pl., C 177-179 CH 132-135 jCHjCH Example 7. A compound of the formula I, where R is hydrogen, methyl, ethyl propyl, butyl, phenyl or benzyl; X is a Bruma or chlorine atom, dissolved in 20 ml of 35% phosphoric acid. The solution is boiled at reflux temperature for 5 hours and produced with blowing compounds of formula 1; Rt. square fC H 117-118 82-83 55-56 C HgCHj 142-143 Claims of obtaining method of y-pyrons of general formula G: LH where R is a hydrogen atom,. alkyl or benzyl, by treatment of the 2H-pyran-3-one derivative with aqueous with a strong acid solution, in order to simplify the process, expand the resource base and product range, the target products, as a 2H-pyran-3-one product, use the compound of formula II: where R has the indicated meanings; X is a chlorine or bromine atom, and the process is carried out at the boiling point of the reaction medium. Sources of information taken into account during the examination 1. Lichtenthales F.H. and Heldel P. Intermediates In-Formation of -Pyrones from Hexose Derivatives. A Simple Synthesis of Kojic Acid and Hydroxymaltol.- Angew. Chem I nternat Ed I t, 1969, v.S, p. 978 (prototype).
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    同族专利:
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    ZA773566B|1978-05-30|
    RO78954A|1982-04-12|
    US4082717A|1978-04-04|
    JPS5810573A|1983-01-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US4191693A|1976-11-12|1980-03-04|Pfizer, Inc.|Preparation of gamma-pyrones from 3-substituted furans|
    JPS5481273A|1977-12-12|1979-06-28|Shin Etsu Chem Co Ltd|Preparation of pyranone halide|
    DE3067027D1|1980-01-11|1984-04-19|Ici Plc|Process for the preparation of 1,4-dialkylbut-2-ene-1,4-diones|
    US4742078A|1983-01-17|1988-05-03|Otsuka Kagaku Kabushiki Kaisha|Pyran derivatives|
    HU191198B|1983-01-17|1987-01-28|Otsuka Kagaku Kk|Acaricide compositions containing pyrane derivatives as active ingredients and process for preparing the active substances|
    DE3401362C3|1983-02-04|1998-03-26|Fev Motorentech Gmbh|Process for controlling four-stroke piston internal combustion engines|
    US4443621A|1983-03-14|1984-04-17|Pfizer Inc.|p-Nitrophenyl 3-bromo-2,2-diethoxy-propionate and synthetic utility therefor|
    JPH0448928B2|1986-02-01|1992-08-10|Mazda Motor|
    JPH0235477Y2|1986-12-01|1990-09-26|
    JPH0291625U|1989-01-09|1990-07-20|
    DE4322480C2|1993-07-06|1996-05-02|Meta Motoren Energietech|Device for the variable valve control of internal combustion engines|
    WO1995029908A1|1994-04-29|1995-11-09|Pfizer Inc.|Maltol recovery|
    US5939565A|1997-11-03|1999-08-17|Cultor Food Science, Inc.|Recovery of γ-pyrones|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    US71090176A| true| 1976-08-02|1976-08-02|
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