I. Roling et al., ANALYTICAL AND SENSORY CHARACTERIZATION OF GAMMA-THIOLACTONES AND DELTA-THIOLACTONES, Journal of agricultural and food chemistry, 46(2), 1998, pp. 668-672
gamma-Thiolactones [5-alkyldihydro-2(3H)-thiaphenones] and delta-thiol
actones (6-alkyltetrahydro-2H-thiopyran-2-ones) were synthesized via i
sothiouronium salts by reaction of the corresponding oxygen-containing
lactones with thiourea and hydrobromic acid. The identity of the comp
ounds was confirmed by means of IR, MS, and H-1 and C-13 NMR. Separati
on of the enantiomers of the thiolactones was achieved by capillary GC
using akis(2,3-di-O-methyl-6-O-TBDMS)-beta-cyclo-dextrin as stationar
y phase. The substitution of oxygen by sulfur induces tropical fruit n
otes, which are more pronounced for the beta-thiolactones. Odor thresh
olds are dependent on ring size and chain length.