3-Alkyl-p-menthan-3-ol derivatives: synthesis and evaluation of their physiological cooling activity
摘要:
Different 3-alkyl-p-methan-3-ol derivatives provide a strong physiological cooling effect with potential application as food and cosmetic additives. In order to investigate the influence of the chemical structure on the cooling sensation, the stereoselective syntheses of 29 different 3-alkyl-p-methan-3-ol derivatives were accomplished. All the compounds obtained are odorless and were evaluated by taste, considering two sensations: a cooling effect and bitterness. The results of this structure-activity relationship study highlight that compounds with a (1R,4S)-configuration are the isomers with the more intense cooling effect and lower bitterness. In addition, the structure of the 3-alkyl chain affected the latter properties. Increasing the chain length over two carbon atoms does not change the cooling power, but enhances the bitterness with the additional feature that the branched isomers are considerably more bitter than the linear ones. Overall, the 3-alkyl-p-menthan-3-ol isomers with the best quality in terms of high cooling power and low bitterness are (1R,4S)-3-(hydroxymethyl)-p-menthan-3-ol diasteroisomers (-)-38 and (-)-42. (C) 2008 Elsevier Ltd. All rights reserved.
Synthesis of Tetrahydrofurans by Cyclization of Homoallylic Alcohols with Iodine/Iodine(III)
作者:Ramon S. Vasconcelos、Luiz F. Silva、Athanassios Giannis
DOI:10.1021/jo102413u
日期:2011.3.4
Tetrahydrofuran derivatives can be obtained by cyclofunctionalization of homoallylicalcohols bearing a terminal double bound by using [hydroxy(tosyloxy)iodo]benzene (HTIB, Koser’s reagent) in the presence of a catalytic amount of I2 (20 mol %) in MeOH under mild conditions. This transformation is an overall5-endo-trig cyclization, which occurs by two different pathways. The first is a 4-exo-trig
Investigations of the Scope and Mechanism of the Tandem Hydroesterification/Lactonization Reaction
作者:Lijun Wang、Paul E. Floreancig
DOI:10.1021/ol048378f
日期:2004.11.1
alcohols and 2-pyridylmethyl formate in the presence of Ru(3)(CO)(12) initiates a tandem sequence of hydroesterification and lactonization. Mechanistic studies suggest that regioselectivity and overall reaction efficiency are governed by the relative rates of reductive elimination and beta-hydride elimination for the alkylruthenium intermediates.
A new convenient method for the asymmetric transfer allylation of aromatic aldehydes was developed. The reaction gave the best results using a chiral allyl donor molecule derived from (–)-menthone in the presence of heteropoly acids supported on silica gel undersolvent-freeconditions, and the desired homoallylic alcohol derivatives were obtained in good yields with good to high enantioselectivity
3-phenylpropanal 2a via an allyl-transferreactionfrom a chiral allyl donor, (1R,2S,5R)-1-allylmenthol, gave (R)-1-phenylhex-5-en-3-ol 3b enantioselectively. The optical yield (ee)of (R)-3b, however, decreased with increasing chemical yield, and the chemical yield increased with increasing reaction time. The racemization takes place via an acid-catalyzed allyl-transferreactionfrom (R)-3b to 2a.
Tandem Cross-Metathesis/Hydrogenation/Cyclization Reactions by Using Compatible Catalysts
作者:Janine Cossy、Frédéric Bargiggia、Samir BouzBouz
DOI:10.1021/ol027347m
日期:2003.2.1
[GRAPHICS]A one-pot tandem cross-metathesis/hydrogenation/cyclization procedure was achieved at room temperature, under 1 atm of hydrogen, in the presence of a ruthenium catalyst and PtO2 showing the compatibility of the two catalysts. This tandem reaction allows the synthesis of substituted lactones and lactols from acrylic acid and acrolein, respectively, in the presence of unsaturated alcohols.