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Pyran-2-ones, methylation

The second variant is the reaction of a pyran-2-one (methyl coumalate, 313) as dienophile with a cyclopentadiene (314). The balance between the dienic and dienophilic capabilities of pyran-2-one is tipped in favour of the latter by the electron-withdrawing properties of the carboxylic ester group and this fine balance enhances the potential of these compounds as synthons (72CC388). [Pg.688]

The most common method for the preparation of pyrazoles from other heterocycles is from pyranone-type compounds. Condensation of 2,3-dihydro /7-pyran -ones 787 with various aryl hydrazines in the presence of montmorillonite KSF clay under mild conditions proceeded rapidly to afford enantiomerically pure 5-substituted pyrazoles 788 (Equation 172) <2004TL6033>. Comparable results were obtained when arylhydrazines were reacted with 2-formyl glycals under microwave irradiation <2004TL8587>. Phenylhydrazine and hydrazine were reacted with 3-acetyl-4-hydroxy-6-methyl-2/7-pyran-2-one to afford 4-acetoacetyl-3-methylpyrazolin-5-ones, which were employed in the synthesis of bipyrazoles and pyrazoloisoxazoles <1999JHC1291>. Reaction of 3,3-dialkyl-6-(trifluoromethyl)-2,3-dihy-dro -pyrones with hydrazine hydrate afforded 3-(trifluoromethyl)-5-substituted-pyrazoles <1998RCB1365>. [Pg.104]

Hydroxymaltol (3,5-dihydroxy-2-methyl-4H-pyran-4-one) Methyl-4(7T)-pyran-4-one (2-methyl-4/7-pyran-4-one)... [Pg.231]

The structure of pironetin was determined to be (5/ ,6/ )-5-ethyl-5,6-dihydro-6[(jE )-(2/ ,35,4/ ,55)-2-hydroxy-4-methoxy-3,5-dimethyl-7-nonenyl]-2H-pyran-2-one by FAB-MS, H and 13C NMR, COSY, COLOC, DEPT, IR, X-ray crystallographic analyses and adapted Mosher s method to determined the absolute configuration [74]. The biosynthesis of pironetin appeared to involve assembly of acetate, propionate and butyrate precursors. Four fermentation experiments were carried out in order to determine the biosynthetic origin of the carbon skeleton and oxygen atoms of pironetin. [1-13C] Acetate, [2-13C]acetate, [1,2-13C] acetate, [l-13C]propionate, [l-1 C]butyrate and L-[methyl-I3C]methionine were led separately to Streptomyces sp. culture and pironetin was isolated and purified. Analysis of pironetin by 13C NMR showed that pironetin was derived from four acetate units, two propionate units, one butyrate unit and one methyl unit of methionine [78] (Fig. 4). [Pg.29]

Me ether 6-Methoxy-2-methyl-2Yi-pyran 3(6H)-one. Methyl a-D aculoside [33647-82-4]... [Pg.634]

Cyclization. Constmction of ben2otrifluorides from aHphatic feedstocks represents a new technique with economic potential. For example, l,l,l-trichloro-2,2,2-trifluoroethane [354-58-5] and dimethyl itaconate [617-52-7] form 4-methoxy-6-trifluoromethyl-2JT-pyran-2-one [101640-70-4] which is converted to methyl 3-(trifluoromethyi)ben2oate [2557-13-3] ixh. acetjdene or norbomadiene (125). [Pg.320]

Chemically, wood tar is a complex mixture that contains at least 200 individual compounds, among which the foUowing have been isolated (1) 2-methoxyphenol, 2-methoxy-4-ethylphenol, 5-meth5i-2-methoxyphenol, 2,6-x5ienol, butyric acid, crotonic acid, 1-hydroxy-2-propanone, butyrolactone, 2-methyl-3-hydroxy-4JT-pyran-4-one, 2-methyl-2-propenal, methyl ethyl ketone, methyl isopropyl ketone, methyl furyl ketone, and 2-hydroxy-3-methyl-2-cyclopenten-l-one. [Pg.335]

Acetic acid, dehydro- — see also Pyran-2-one, 3-acetyl-4-hydroxy-6-methyl-fungicidal properties, 3, 883 H NMR, 3, 581 reactions, 3, 690 with amines, 3, 700 reduction, 3, 843 synthesis, 2, 90 tautomerism, 3, 643... [Pg.508]

Allomaltol, methyl — see Pyran-4-one, 5-methoxy-2-methyl-Allopurinol applications, 5, 343 metabolism, 1, 237 synthesis, 5, 316, 340 tautomerism, 5, 308 xanthine oxidase inhibition by, 1, 173 Allopurinol, oxy-applications, 5, 343 synthesis, 5, 316 Alloxan... [Pg.514]

Butenoic acid, 2-benzamido-3-methyl-synthesis, 1, 447 But-2-enoic acid, 3-methyl-pyran-2-one synthesis from, 3, 796 But-3-enoic acid... [Pg.572]

Maltol — see Pyran-4-one, 3-hydroxy-2-methyl-Maltol, ethyl — see Pyran-4-one, 3-ethoxy-2-methyl-Maltol, methyl — see Pyran-4-one, 3-methoxy-2-methyl-Mandelic acid ethyl ester, 1, 310-311 Manganaindene reactions, 1, 671 Mannich bases dehydro... [Pg.700]

Naphtho[ 1,2-h]pyran-4-one, 3,6-diacetyl-2-methyl-deacetylation, 3, 713 Naphtho[ 1,2-h]pyran-4-one, 5,6-dihydro-synthesis, 3, 811... [Pg.706]

Pyran-2-one, 3-acetyl-4-hydroxy-6-methyl-synthesis, 3, 792 Pyran-2-one, 4-alkoxy- H NMR,3, 581 Pyran-2-one, 6-alkoxy-synthesis, 3, 791... [Pg.764]

Pyran-2-one, 3,5-bis(methoxycarbonyl)-6-methyl-synthesis, 3, 789-790 Pyran-2-one, 3-bromo-synthesis, 3, 679 Pyran-2-one, 4,6-dialkoxy-reactions... [Pg.765]

Pyran-2-one, 5,6-dibromo-5,6-dihydro-reactions, 3, 735 Pyran-2-one, 5,6-dihydro-allylic bromination, 3, 799 dehydrogenation, 3, 724, 799 H NMR,3, 581 synthesis, 3, 841, 843 Pyran-2-one, 4,6-dimethyl-irradiation, 3, 677 photochemistry, 3, 678 Pyran-2-one, 5,6-dimethyl-chloromethylation, 3, 680 conformation, 3, 631 Pyran-2-one, 5-f ormyl-IR Spectra, 3, 595 Pyran-2-one, 6-formyl-IR spectra, 3, 595 Pyran-2-one, 5-halo-synthesis, 3, 799 Pyran-2-one, 3-hydroxy-IR spectra, 3, 595 Pyran-2-one, 4-hydroxy-methylation, 2, 57 3, 676 pyran-4-one synthesis from, 3, 816 reactions with phosphorus oxychloride, 2, 57 synthesis, 3, 792, 794, 795, 798 tautomerism, 2, 56 3, 642 Pyran-2-one, 4-hydroxy-6-methyl-methylation, 3, 692 reactions... [Pg.765]

Pyran-2-one, 4-hydroxy-6-methyl-5,6-dihydro-halogenation, 3, 723 reactions... [Pg.765]

Pyran-2-one, 4-methoxy-6-methyl-aromaticity, 3, 635 mass spectra, 3, 607 UV spectra, 3, 599... [Pg.765]

Pyran-2-one, 4-methoxy-6-( 1 -propenyl)-synthesis, 3, 690 Pyran-2-one, 6-methyl-bromination, 3, 690 Pyran-2-one, 6-(2-methylpropenyl)-synthesis, 3, 796 Pyran-2-one, 3-methylthio-synthesis, 3, 796 Pyran-2-one, 3-nitro-6-phenyl-oxidation, 3, 681 Pyran-2-one, 6-phenyl-chlorination, 3, 679... [Pg.765]

Pyran-3-one, 2-methyltetrahydro-reduction, 3, 729 Pyran-3-one, 6-methyltetrahydro-mass spectra, 3, 616 Pyran-3-one, 5-phenyl-synthesis, 3, 843-844 6H-Pyran-3-one, 6-ethoxy-2-methyl epoxidation, 3, 725 Pyran-4-one, 2-alkoxy- H NMR, 3, 581 Pyran-4-one, 2-amino-reactions, 2, 55 synthesis, 3, 814... [Pg.765]

Pyran-4-one, 3-ethoxy-2-methyl-, 3, 612 IR spectra, 3, 595 Pyran-4-one, 2-hydroxy-tautomerism, 3, 642 Pyran-4-one, 3-hydroxy-appiication, 3, 880 synthesis, 2, 91 3, 815 Pyran-4-one, 5-hydroxy-2-hydroxymethyl- C NMR, 3, 588 mass spectra, 3, 611... [Pg.766]

Pyran-4-one, 2,2,5-trimethyl-2,3-dihydro-photodimerization, 3, 720 4H-Pyran-4-one, 2,3-dihydro-2,3,5-trimethyl-6-( 1 -methyl-2-oxobutyl)-synthesis, 3, 844 Pyranones alkylation, 2, 56 aromaticity, 3, 632, 633 C NMR, 3, 587, 635 H NMR, 3, 580 cardiac glycosides, 3, 883 chromone synthesis from, 3, 830 colour couplers... [Pg.766]

See other pages where Pyran-2-ones, methylation is mentioned: [Pg.195]    [Pg.690]    [Pg.1306]    [Pg.770]    [Pg.132]    [Pg.13]    [Pg.44]    [Pg.44]    [Pg.44]    [Pg.44]    [Pg.44]    [Pg.44]    [Pg.44]    [Pg.44]    [Pg.45]    [Pg.45]    [Pg.45]    [Pg.45]    [Pg.509]    [Pg.582]    [Pg.694]    [Pg.765]    [Pg.765]    [Pg.765]    [Pg.766]    [Pg.766]   
See also in sourсe #XX -- [ Pg.281 ]

See also in sourсe #XX -- [ Pg.281 ]

See also in sourсe #XX -- [ Pg.281 ]



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3-Hydroxy-2-methyl-4H-pyran-4-one

Methyl-4//-pyrans

Pyran-4-one, 3-hydroxy-2-methyl

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