4- Hydroxy-2H-pyran-2-ones

So far, most microorganisms and enzymes derived therefrom have been used in the reduction of a single keto group of p-keto or a-keto compounds [68-71], Recently, Patel et al. [72] have demonstrated the stereoselective reduction of 3,5-dioxo-6-(benzyloxy)hexanoic acid, ethyl ester (41), to (3,S, 5R)-dihydroxy-6-(benzyloxy)hexanoic acid, ethyl ester (42a) (Fig. 14). The compound (42a) is a key chiral intermediate required for the chemical synthesis of [4-[4a,6P(E)]]-6-[4,4-bis(4-fluorophenyl)-3-(l-methyl-lH-tetrazol-5-yl)-l,3-butadienyl]-tetrahydro-4-hydroxy-2H-pyran-2-one, compound R-( + )-(43), a new anticholesterol drug that acts by inhibition of HMG CoA reductase [73], Among various microbial cultures evaluated for the stereoselective reduction of diketone (41), cell suspensions of Aci-... 

RN Patel, CG McNamee, LJ Szarka. Enantioselective enzymic acetylation of racemic [4-[4a,6P(E)]]-6-[4,4-bis(4-fluorophenyl)-3-(l-methyl-lH-tetrazol-5-yl)-l,3-butadienyl]tetrahydro-4-hydroxy-2H-pyran-2-one. Appl Microbiol Biotechnol 38 56-60, 1992. 

The 4-hydroxy-2H-pyran-2-one moiety is a key structural feature in a recently discovered new class of non-peptidic HIV protease inhibitors. Therefore, the synthetic methodologies were extended to allow the functionalization of commercially available chemicals. Direct arylation of the pyrone ring at the C-3 and C-5 positions had not been reported until the re-... 

FMev tetrahydro-4-fluoro-methyl-4-hydroxy-2H-pyran-2-one 200 4, 9, 18, 22-26 100 7.8- 45+21 99+7... 

Phloroglucinols Malonyl dichloride reacts with keto enol ethers to form phlo-roglucinols (2) and/or 4-hydroxy-2H-pyran-2-ones (3), which are readily convertible into phloroglucinols. 

H-Pyran-2-one, 5,6-dihydro-4-hydroxy-2H-Pyran-2-one, hydroxy-methyl- 3746, 3747 3430 ... 

Sliskovic DR, Blankley CJ, Krause BR, et al. Inhibitors of cholesterol biosynthesis. 6. trans-5-[2-(-N-heteroaryl-3,5-disubstituted-pyrazol-4-yl)ethyl/ethenyl]tetrahydro-4-hydroxy-2H-pyran-2-ones. J Med Chem 1992 35 2095-2103. 

On treatment with KOH in methanol, 6-phenacyl-4-hydroxy-2H-pyran-2-one (45) undergoes isomerization to 2-benzoylphloroglucinol (47) [16] ... 

The most important furans in major food commodities are 4-hydroxy-2H-furan-3-ones (8-159), which are characterised by a planar arrangement of molecules and the same configuration of the enol, hydroxyl and oxo groups. Furanones occur as racemic mixtures because of their keto-enol tautomerism (Figure 8.71). Some other compounds have analogous structures as furanones, such as maltol, 3-hydroxy-2H-pyran-2-one and cyclopentenolones. All compounds with this structure resemble more or less the caramel... 

H-Pyran-2-one, 3-acetyl-4-hydroxy-6-methyl-dipole moment, 3, 626 <37JCS1088>... 

The other factor that may determine the type of cell death is the chemical structure of inducing agents [14]. We have recently found that u,(>-unsaluraled ketones such as 4,4-dimethyl-2-cyclopenten-l-one, a-methy-lene-y-butyrolactone, 5,6-dihydro-2H-pyran-2-one [15], codeinone [16], and morphinone [17] and a-hydroxylketones such as 3,3,3-trifluoro-2-hydroxy-1-phenyl-1-propanone induced caspase-independent cell death [18], induced vacuolization or autophagosome formation engulfing organelles, but without induction of apoptosis markers. 

A process for preparing a tautomeric mixture of the product of Step 3, (R)-3-hexyl-5,6-dihydro-4-hydroxy-6-undecyl-2H-pyran-2-one, (I), and (R)-5,6-dihydro-6-undecyl-2H-pyran-2,4(3H)-dione, (II), and (2), respectively, is described (3). 

At ambient temperature, 4-hydroxy-6-methyl-2H-pyran-2-one (1.4 mmol) added portion-wise to glycine (1.4 mmol) dissolved in 1.4 L 1M NaOH, refluxed 1 hour, and acidified with 500 ml 3 M HCl. The mixture was concentrated to half its volume, the precipitate filtered, washed, and the product isolated in 70% yield, mp = 240 °C. 

Synthesis of ( )-trans-6-[4,4-bis(4-fiuorophenyi)-3-(1-methyi-1H-tetrazol-5-yl)-1 (E), 3-[2- C]butadienyi-4-hydroxy-3,4,5,6-tetrahydro-2H-pyran-2-one... 

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