Bestimmung der absoluten Konfiguration von chiralen Thiolen durch ¹H‐NMR‐Spektroskopie diastereomerer Thiolester

Abstract

Filtrat. Es wird abfiltriert und zweimal rnit Diethylether gewaschen. AnschlieDend trocknet man (2) bei Raumtemperatur im Vakuum. Ausbeute 21.8g (61 %); Fp=213 bis 215"C, Lit.

Enantiomeric Distribution of 2-Pentanethiol in Guava Fruit (Psidium guajava L.) by Multidimensional Gas Chromatography with Sulfur Chemiluminescence Detection

“…The absolute configuration of (S)-2-pentanethiol was established by 1 H NMR spectroscopy using its diastereomeric HTA ester according to the method of Helmchen [8,9]. As seen from the 1 H NMR data (Table 1), the resonance of the b-H and c-H in the ester was upfield shifted, thus indicating (S) configuration.…”

“…of 100% (S). The absolute configuration was checked by 1 H NMR using its HTA ester [8,9]. HTA esters of racemic and (S)-2-pentanethiol were formed by adding a solution of 40 mg 2-pentanethiol (0.38 mmol) in dry CCl 4 (10 ml) to a stirred solution of 252 mg (1.5 mmol) of freshly prepared (R)-(-)-phenylpropionyl chloride.…”

Stereoisomere Aromastoffe, XII. 3‐Methyl‐4‐octanolid – „Quercuslacton, Whiskylacton”︁ – Struktur und Eigenschaften der Stereoisomeren

“…139 (45), 138 (lo), 137 (ll), 136 (16), 135 (3), 126 (2), 125 (32), 124 (7), 122 (3), 121 (7), 115 (17), 114 (4), 113 (4), 112 (S), 111 (16), 110 (9). 109 (48), 108 (S), 107 (7), 105 (9,101 (3), 100 (3), 99 (26), 98 (lo), 97 (61), 96 (30), 95 (15). 94 (3,93 (Il), 91 (6), 87 (S), 85 (5), 84 (8), 83 (70), 82 (7), 81 (141, 80 (2), 79 (9).…”

Chirality in flavor chemistry‐recent developments in synthesis and analysis

“…By introduction of the acetyl residue, the primary alcoholic function of 13 is protected, and the 3-mercapto group is esterified with chiral acylchlorides [e.g., (-)-camphanoyl chloride (47)] to give the diastereomeric thiol esters, which are separated by liquid chromatography and transferred into the enantiomers 13a and 13a' by reductive cleavage with LiAlH 4 . Absolute configurations of 13a and 13a' were derived from 'H-NMR spectroscopic behavior of their hydratropic acid thiol esters (44). This method proves the (R)(-) and (5)(+) configuration of the optical isomers 13a and 13a', respectively.…”

“…Absolute configurations were derived from the corresponding HTS-esters according to Helmchen (44). In both cases the first peak eluted from the LC column was analyzed to be 4R-configurated.…”