Synthesis, odour characteristics, and antibacterial activity of optically active cognac lactones

Abstract

In this study, all stereoisomers of cognac lactone (1) were synthesized with over 99% enantiomeric excess via diastereomeric resolution using N‐benzyloxycarbonyl‐l‐proline (N‐Cbz‐l‐proline) as a resolving agent. N‐Cbz‐l‐proline could be applied for the diastereomeric resolution of both syn‐ and anti‐forms and yielded all diastereomers in over 99% diastereomeric excess. The odour properties of racemic and optically active 1 were evaluated for their orthonasal aromas. All the stereoisomers had different odour characteristics and thresholds. In general, the (3S)‐ and (3R)‐forms had fruity and herbal notes, respectively, and (3R,4S)‐1 had the lowest odour threshold at 0.01 ppm. All stereoisomers, except (3R,4S)‐1, showed antibacterial activity against Staphylococcus aureus. Moreover, (3S,4S)‐1 showed high antibacterial activity against both S aureus and Escherichia coli.

Synthesis, Odour Characteristics, and Antimicrobial Activity of Optically Active (<i>Z</i>)-7-Decen-4-olide and Its Derivatives

“…We previously reported that N-Cbz-L-proline is an efficient agent for diastereomeric resolution 13,14,26) . (±) -2a-2f were esterified with N-Cbz-L-proline to give a mixture of diastereomer esters 3a-3f (Scheme 2) .…”

“…1) . Because lactones exhibit antimicrobial activities 10−12) , we previously reported the antimicrobial activities of optically active whisky and cognac lactones against S. aureus 13,14) . Although γ -alkyllactones are typically used in perfumes, these lactones (1a-1f) can be used in new applications if they Abstract: Six optically active (Z)-7-decen-4-olide derivatives (1a-1f) were synthesized in 99% enantiomeric excess using diastereomeric resolution.…”