3511-31-7Relevant academic research and scientific papers
NOVEL 4-(HETEROCYCLOALKYL)BENZENE-1,3-DIOL COMPOUNDS AS TYROSINASE INHIBITORS, PROCESS FOR THE PREPARATION THEREOF AND USE THEREOF IN HUMAN MEDICINE AND ALSO IN COSMETICS
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Page/Page column 24, (2010/06/20)
The present invention relates to novel 4- (heterocycloalkyl) benzene- 1,3-diol compounds corresponding to general formula (I) below: to the compositions containing same, to the process for the preparation thereof and to the use thereof in pharmaceutical or cosmetic compositions for use in the treatment or prevention of pigmentary disorders
The effect of high pressure on the formation of volatile products in a model Maillard reaction
Bristow, Mark,Isaacs, Neil S.
, p. 2213 - 2218 (2007/10/03)
Reaction progress in the formation and subsequent decay of several of the volatile products from a model Maillard reaction between lysine and xylose has been followed at pH 7 and 10 and at elevated pressures. At low pH, the buildup and decay of 5-methyl-4-hydroxy-3(2H)-furanone and several minor products were observed. The application of high pressure results in a much diminished maximum concentration of each although the time to the maximum is unaffected. At pH 10, products contain nitrogen heterocycles with 2-methylpyrazine being the principal one which builds up and only slowly decays with time. Again, the yield is greatly reduced by pressure. The results are interpreted in terms of the inhibition by pressure of the formation of the precursor the Amadori rearrangement product which affects subsequent products. In some instances rates of formation are also found to be slightly inhibited while degradation of these products is accelerated. The corresponding mechanisms are examined in the light of these results.
Tautomerism of the Monohydroxy Derivatives of Five-Membered O, N, and S Heterocycles
Capon, Brian,Kwok, Fu-Chiu
, p. 5346 - 5356 (2007/10/02)
The O-deuterated enolic tautomers 3-deuteroxybenzofuran, 3-deuteroxybenzothiophene, 3-deuteroxyindole, 3-deuteroxy-1-methylindole, 3-deuteroxyfuran, 3-deuteroxythiophene, 2-deuteroxybenzothiophene, and 2-deuteroxythiophene have been generated in solution in mixtures of CD3COCD3, CD3CN, or CD3SOCD3 with D2O by hydrolysis of their trimethylsilyl derivatives in the presence of DCl (1E-3 - 1E-4 M) and characterized by 1H NMR spectroscopy.Solutions of 3-hydroxypyrrole and of 3-hydroxy-1-methylpyrrole were obtained by methanolysis of their trimethylsilyl derivatives,evaporation of the methanol, and immediate dissolution in DMSO-d6.The carbocyclic analogues of the bicyclic heterocyclic enols 3-deuteroxyindene and 2-deuteroxyindene were also generated in solution.Attempts to prepare solutions of 2-deuteroxyfuran, 2-deuteroxypyrrole, and 2-deuteroxy-1-methylpyrrole were unsuccessful.The kinetics of ketonization of the OH forms of these enols have been investigated in water or aqueous acetonitrile solution.The equilibrium constants for the keto-enol tautomerism were also determined either by direct measurement when sufficient enol was present at equilibrium or as the ratio of the rate constant for enolization of the keto form to that for ketonization of the enol form, the former being determined by the iodine-trapping technique.The effect of solvent on the equilibrium constants was also studied.Sufficient data were available for the equilibrium between 3-hydroxyindole and 3-ketoindole for them to be analyzed by the four-parameter equation of Mills and Beak to yield an a value of 2.4 and a b value of -3.0.The pKas of the bicyclic enols were measured. 3-Hydroxybenzofuran and3-hydroxybenzothiophene are stronger acids than 3-hydroxyindole and 3-hydroxy-1-methylindole.The ketonization reactions are general acid and general base catalyzed and their mechanisms are discussed.
REVERSIBLE CARBON PROTONATION IN THE HYDROLYSIS OF HETEROCYCLIC ENOL METHYL ETHERS
Capon, Brian,Kwok, Fu-Chiu
, p. 69 - 76 (2007/10/02)
The kinetics of the hydronium-ion catalysed hydrolysis of the following heterocyclic methyl enol ethers have been measured: 3-methoxybenzofuran, 3-methoxybenzothiophene, 3-methoxyindole, 3-methoxy-1-methylindole, 3-methoxyfuran, 3-methoxythiophene, and 2-methoxythiophene.On the basis of the solvent isotope effect kH/kD = 3.08 and the failure to detect deuterium exchange when the solvent was CD3CN:D2O (9:1 v/v) it was concluded that the rate limiting step in the hydrolysis of 3-methoxybenzofuran is C-protonation.The effect of the ring-oxygen atom was measured by comparing the rate of hydrolysis of 3-methoxybenzofuran with that of 3-methoxyindene which occurs 2100 times faster.In contrast to the behaviour of 3-methoxybenzofuran the isotope effects, kH/kD, for the hydrolyses of 3-methoxyfuran, 3-methoxythiophene, 3-methoxyindole, 3-methoxy-1-methylindole and 2-methoxythiophene are ca 0.4 - 0.5 and deuterium exchange is much faster than hydrolysis when the solvent is CD3CN:D2O (9:1 v/v).It was therefore concluded that with these compound C-protonation is rapid and reversible and that slow step is attack by water on the intermediate cation.
HETEROCYCLIC SILYL ENOL ETHER CHEMISTRY: SYNTHESIS AND REACTIVITY OF 3-TRIMETHYLSILOXYFURAN AND 3-TRIMETHYLSILOXYTHIOPHENE
Camici, Lucia,Ricci, Alfredo,Taddei, Maurizio
, p. 5155 - 5158 (2007/10/02)
The preparation of the title compounds is reported starting from the corresponding bromo derivatives. 3-Trimethylsiloxyfuran gives rise easily to cycloadditions affording bicyclic tetrahydrofuranoic systems.
THE TAUTOMERISM OF HYDROXY DERIVATIVES OF FIVE-MEMBERED OXYGEN, NIRTOGEN, AND SULFUR HETEROCYCLES
Capon, Brian,Kwok, Fu-Chiu,Road, Pokfulam
, p. 3275 - 3278 (2007/10/02)
The unstable enolic tautomers 3-hydroxyfuran, 2- and 3-hydroxy-thiophene, 3-hydroxy-pyrrole, 3-hydroxy-1-methyl-pyrrole and their benzo-derivatives have been generated in solution and the rate and equilibrium constants for their ketoization determined.
Asymmetric synthesis of optically active prostaglandins
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, (2008/06/13)
An asymmetric synthesis of optically active prostaglandin F2α from cyclopentadiene including intermediates in this synthesis.
