Stereochemical Studies of Odorous 2-Substituted-3(2<i>H</i>)-furanones by Vibrational Circular Dichroism

Chiral naturally occurring aroma compounds often exhibit enantiomeric excesses due to their stereoselective biogenesis. In general, significant organoleptic differences are perceived between these enantiomers. Chiral 2-substituted-3(2H)-furanones, featuring a unique keto−enol tautomer, the cause of their racemization, have been known to play an important role in flavor because of their extremely low threshold values and their burnt sugar odor characteristics. Since the discovery of these important aroma chemicals, they have been used in large quantities as raw materials in the flavor and fragrance industry. However, absolute configurations of these furanone derivatives have remained ambiguous for the past 40 years. Here optical resolutions of 2,5-dimethyl-4-hydroxy-3(2H)-furanone, 2,5-dimethyl-4-methoxy-3(2H)-furanone, and 4-acetoxy-2,5-dimethyl-3(2H)-furanone were accomplished using chiral CO2 supercritical fluid chromatography (SFC). Their absolute configurations were unraveled for the first time using the vibrational circular dichroism (VCD) technique as well as by chemical relay reactions. Odor evaluation of each enantiomer revealed relationships between their configurations and odor activities

Stereochemical Study of Chiral Tautomeric Flavorous Furanones by Vibrational Circular Dichroism

2-Substituted-3(2H)-furanone derivatives are industrially significant aroma compounds possessing a unique keto−enol tautomeric feature causing their racemization. Absolute configurations of two flavorous furanones, which have remained unclear for the past 40 years since their discovery, were clarified by the vibrational circular dichroism technique as well as chemical relay reactions. Odor evaluation of each enantiomer revealed relationships between their configurations and their odor activities

<b>Low Handgrip Strength (Possible Sarcopenia) with Insulin Resistance Is Associated with Type 2 Diabetes Mellitus, </b>Supplementary Tables.

Supplementary Table 1. The number of individuals with lipid-lowering and diabetes drugs in groups.Supplementary Table 2. Associations between the prevalence of type 2 diabetes and IR-Possible sarcopenia in subjects with IR.Supplementary Table 3. Associations between the prevalence of type 2 diabetes and IR-Sarcopenia.</p