Phenylalkenal compounds, due to the presence of aroma-contributing groups such as aromatic rings and aldehyde groups in their molecular structure, are a key class of odorants with significant applications in the flavor and fragrance industry. A series of six novel phenylalkenals were synthesized via a cross-aldol condensation of phenylacetaldehyde with various alkyl aldehydes using sodium acetate as a base in anhydrous ethanol. The resulting compounds were characterized by nuclear magnetic resonance (¹H NMR, ¹³C NMR), infrared spectroscopy (IR), and high-resolution mass spectrometry (HRMS). Their odor characteristics were evaluated by a sensory panel. Their thermal behaviors were analyzed by thermogravimetry-derivative thermogravimetry (TG-DTG), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). TG-DTG analysis deter- mined the temperature range corresponding to 90% mass loss and the temperature at the maximum mass loss rate for each compound. The results revealed that, with the exception of compound 3d, the other five compounds satisfied the volatility requirements for flavor compounds in heat-not-burn (HNB) cigarettes. Additionally, Py-GC/MS studies at 400  ℃ showed that all six compounds underwent partial pyrolysis, generating various aromatic products that contributed to flavor profiles. The antioxidant evaluation revealed that all six compounds exhibited significant antioxidant activity. Notably, compound 3c demonstrated the strongest scavenging capacity toward ABTS^＋•, while compound 3e showed the highest scavenging efficiency against DPPH•. This study provides new candidate compounds for the development of novel flavor substances, particularly those suitable for HNB cigarettes, with promising potential in areas such as tobacco product formulation and food additives.

Key words: aldol condensation, phenylalkenal, flavor and fragrance, thermal behavior, antioxidation