Synthesis and flavor properties of some alkyl-substituted .alpha.-pyrone derivatives

An Expedient Synthesis of Olfactory Lactones by Intramolecular Hydroacylalkoxylation Reactions

“…In all cases, the selectivity for the trans isomer is higher than that previously observed for the cyclisation of 5 (Scheme ), with ratios ranging from 1:4.3 (Table 1, Entry 5), up to 1:11.5 (Entry 1). In comparison, δ‐lactones 8a – c , also known to have unique olfactory properties,17 were obtained as an inseparable mixture of cis and trans isomers with ratios between 1:1 and 1:2. Their identity was established by LC‐MS and comparison with literature data.…”

Two Novel and Simple Approaches to ‘CD45 Protein Tyrosine Phosphatase Inhibitor’ (Z)-Pulchellalactam and Derivatives

“…Although that reaction route is clearly less regioselective than the previous approach, it has the advantage of giving only these two regioisomers, which are easily separable by classical flash chromatography over silica gel and were isolated with 30 and 50% yield, respectively. The 6-isopropyl α-pyrone 8 obtained is known to exhibit flavour properties 29 and antifungal activity. 30 To our knowledge, only one report of the syn-…”

“…Compounds 5, 16 7, 21 and 8 29 were described previously. All other reagents were purchased from commercial suppliers.…”

The chemistry of the Bio-Control Agent, Trichoderma Harzianum

“…A different procedure that was used to prepare a range of 6-alkyl-2H-pyran-2-ones, involved the acylation of methyl but-3-enoate and a thermal cyclization. 17 The dehydrogenation of 6-pentyl-3,4dihydropyran-2-one 5, obtained by the cyclization of 5-oxodecanoic acid, provided another method 18 although the dehydrogenation has proved to be rather unreliable.…”