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4- hydroxy-5,4-dihydro-2-pyrone

Hovorka SW, Hageman MJ, Schoneich C. Oxidative degradation of a sulfonamide-containing 5,6-dihydro-4-hydroxy-2-pyrone in aqueous/organic cosolvent mixtures. Pharm Res 2002 19 538-545. [Pg.234]

The isomeric 6-hydroxy-2-pyrone (glutaconic anhydride) and its 4-methyl analog (47) react similarly with aryldiazonium salts and on hydrolysis with dilute alkali or acid the hydrazones (48) are transformed into l-aryl-6-oxo-l,6-dihydro-3-pyridazinecarboxylic acids or their 4-methyl analogs (49) in variable yields (28-74%). [Pg.240]

DIELS-ALDER REACTIONS Benzocyclopropene. 1,2-BisC3-tosyIethoxycarbonyl)-diazene. Cyclobutadiene iron tricarbonyl. 1,2-Dicyanocyclobutene. Diethyl ketomalonate. 1,3,4,6-Heptatetraene. 2-Hydroxy-5-oxo-5,6-dihydro-2/f-pyrone. 3-Hydroxy-2-pyrone. Isopropylidene isopropylidenemalonate. Lithium tetra-methylpiperidide. 4-Methoxy-5-acetoxymethyl-o-benzoquinone. 4-Methoxy-5-methyl-o-benzoquinone. frans-l-Methoxy-3-trimethyl-silyloxy-l,3-butadiene. Per-fluorotetramethylcyclopentadiene. 4-Phenyl-l, 2,4-triazoline-3,5-dione. Potassium f-butoxide. [Pg.780]

Romero, D.L., Tommasi, R.A., Janakiraman, M.N., Strohbach, J.W., Turner, S.R., et al. (1996) Structure-based design of HIV protease inhibitors 5,6-dihydro-4-hydroxy-2-pyrones as effective, nonpeptidic inhibitors. J. Med. Chem. 39 4630-4642. [Pg.443]

Figure 8.18 Scaffold progression in the discovery of the HIV protease inhibitor Aptivus (tipranavir). (Turner, S.R., et al. Tipranavir (PNU-140690) A potent, orally bioavailable nonpeptidic HIV protease inhibitor of the 5,6-Dihydro-4-hydroxy-2-pyrone sulfonamide class. J. Med. Chem. 1998, 41, 3467-3476.)... Figure 8.18 Scaffold progression in the discovery of the HIV protease inhibitor Aptivus (tipranavir). (Turner, S.R., et al. Tipranavir (PNU-140690) A potent, orally bioavailable nonpeptidic HIV protease inhibitor of the 5,6-Dihydro-4-hydroxy-2-pyrone sulfonamide class. J. Med. Chem. 1998, 41, 3467-3476.)...
An aq. soln. of 5-carbethoxy-2- -hexyl-2,3-dihydro-6-methyl-4-pyrone and NaOH stirred 24 hrs. at 0-2°, then acidified with HCl -> 3-acetyl-6- -hexyl-5,6-dihydro-4-hydroxy-2-pyrone. Y 77.9%. K. Sato, S. Inoue, and M. Ohashi, Bull. Chem. Soc. Japan 46, 1288 (1973). [Pg.84]

Dihydro-2f/-pyran-2-one has been prepared by reductive cycliza-tion of 5-hydroxy-2-pentynoic acid [2-Pentynoic acid, 5-hydroxy-], which is obtained in two steps from acetylene [Ethyne] and ethylene oxide [Oxirane] 3 and by the reaction of dihydropyran [277-Pyran, 3,4-dihydro-] with singlet oxygen [Oxygen, singlet].4,5 2ff-Pyran-2-one has been prepared by pyrolysis of heavy metal salts of coumalic acid [2//-Pyran-5-carboxylic acid, 2-oxo-],8 by pyrolysis of a-pyrone-6-carboxylic acid [211 - Pyran-6-carboxyl ic acid, 2-oxo-] over copper,7 and by pyrolysis of coumalic acid over copper (66-70% yield).8... [Pg.51]

The Deng group identified QN-derived thiourea 121 and QD -derived thiourea 124 to be also efficient promoters of enantio- and diastereoselective Diels-Alder reactions between the 2-pyrone diene 3-hydroxypyran-2-one and the dienophiles fumaronitrile, maleonitrile as well as acrylonitrile, while various C9-hydroxy acylated and alkylated (dihydro)cupreines and (dihydro)cupreidines failed for the same reactions under identical conditions (e.g., 97% yield, 15% ee, 64 36 endoxxo) [289], Catalysts 121 and 124 (5mol% loading), however, produced the corresponding Diels-Alder adducts 1-3 with synthetically useful enantioselectivities (85-... [Pg.274]

Dimethoxyoxetanes.1 In the presence of ZnCl2, this ketal reacts with 0-hydroxy aldehydes to give 2,2-dimethoxyoxetanes, which can be converted into 4-hydroxy-3-methyl-8-lactones and 5,6-dihydro-2-pyrones. In one case, an optically active lactone was obtained in 80% ee from an optically active y-hydroxy aldehyde. [Pg.139]

Hydrogenolysis of 2-pyrone derivatives to give open-chain products occurs especially readily when phenyl group is substituted in the 6 position.237,238 4-Ethoxy- and 4-hy-droxy-6-phenyl-5,6-dihydro-2-pyrones were hydrogenated to give 3-ethoxy-5-phenyl-2-pentenoic acid and 3-hydroxy-5-phenylvaleric acid, respectively, over Raney Ni at room temperature and 0.3 MPa H2 (eq. 12.126).237... [Pg.560]

The reaction of benzaldehyde with the stabilized allyl anion 205 (cf. equation 15) affords the hydroxy ester 206, which cyclizes to the dihydro-a-pyrone 207 on distillation (equation 87)34. [Pg.1401]

Kojic acid (J2-dihydro-3-hydroxy-6-hydroxymethyl-y-pyrone) ... [Pg.273]

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]

Ehnenhorst, H. Dihydro-y-pyrones in tobacco smoke. Identification of 2,3-dihydro-5-hydroxy-6-methyM//-pyran -one in cigarette smoke CORESTA 1978 Symp., Sofia, Bulgaria, CORESTA Inf. Bull., Spec. Edition 1978 Paper S05, 114—115. [Pg.1305]

Ehnenhorst, H. and G. Nicolaus Dihydro-y-pyrone im Tabakrauch. Nachweis von 2,3-Dihydro-5-hydroxy-6 -methyl-4//-pyran-4-one in Rauch von Cigaretten aus Burley-, Vhginia-, und Orienttabaken [Dihydro-y-pyrones... [Pg.1305]

Hydroxy-6-propenyl-2-pyrone heated 3 hrs. at 100° with crotonoyl diloride in tetrachlorethane in the presence of TiCl4 3,4-dihydro-2-methyl-7-propenyl-2H,5H-pyrano[4,3-b]pyran-4,5-dione. Y 70%. K. Kato, Y. Hirata, and S. Yama-mura, Chem. Commun. 1969, 95. [Pg.197]

Nagumo, S.T., T. Toyonaga, T. Inoue, and M. Nagai New Glucosides of a 4-Hydroxy-5-methylcoumarin and a Dihydro-a-pyrone from Gerbera jamesonii hybrida. Chem. Pharm. Bull. (Japan), 37, 2621 (1989). [Pg.202]

Crude methyl 6-benzyloxy-5-hydroxy-2-decynoate added to a soln. of Na in methanol and stirred 22 hrs. at 25° -> 4-methoxy-5,6-dihydro-6-(l-benzyloxy-pent-l-yl)-2H-pyran-2-one. Y 82%. F. e., also from the acids, s. R. M. Carlson and A. R. Oyler, Tetrah. Let. 1974, 2615 5,6-dihydro-2-pyrones s. a. J. Org. Chem. 40,1610 (1975). [Pg.381]

Chloro ulfonyl isocyanate and isoprene in ether give 5-hydroxy-3-methyl-2-pentenoic acid lactone (4-methyl-5,6-dihydro-2-pyrone, XII-98) and 5-amino-3-methyl-3-pentenoic acid lactam (4-methyl-3,6-dihydro-2-pyridone, XII-99) by hydrolysis of intermediate N-sulfochlorides that were not isolated ... [Pg.617]


See other pages where 4- hydroxy-5,4-dihydro-2-pyrone is mentioned: [Pg.122]    [Pg.64]    [Pg.91]    [Pg.230]    [Pg.91]    [Pg.812]    [Pg.47]    [Pg.592]    [Pg.299]    [Pg.373]    [Pg.79]    [Pg.432]    [Pg.534]    [Pg.222]    [Pg.257]    [Pg.244]    [Pg.22]    [Pg.73]    [Pg.394]    [Pg.122]    [Pg.183]   
See also in sourсe #XX -- [ Pg.122 ]




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3-Hydroxy-2,3-dihydro

4-Hydroxy-2-pyrones

5,6-Dihydro-2-pyrones

5.6- Dihydro-4-hydroxy-2-pyrones

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