Abstract
3-Methyl-2-cyclopentene-2-ol-1-one (I) and 3-ethyl-2-cyclopentene-2-ol-1-one (II) were identified as new tobacco smoke constituents by gas chromatography and mass spectrometry. After clean-up by thick-layer and thin-layer chromatography and conversion into the methylenolethers by reaction with methanol and HCl, the methylethers of (I) and (II) were identified by high resolution gas chromatography on glass capillary columns and mass spectrometry. The concentration of (I) in tobacco smoke varies according to the tobacco type. Oriental, Virginia and Burley tobaccos were compared. The amounts of (I) and (II) in the smoke of the Oriental tobaccos were at least 0.12 mg/cigarette and 0.048 mg/cigarette respectively. Traces of (I) and (II) were also found in Latakia tobacco. (I) itself has a characteristic aroma of ''burnt sugar'' and a taste which can be described as maple-licorice with a suggestion of walnut. This means that (I) is a flavour constituent of tobacco smoke. But more interesting is the fact that (I) acts as a flavour enhancer and has a modifying effect on the flavour produced by phenols, which results in a ''smoky'' rather than a ''phenolic'' or ''cresotic'' character. We think that substances like the two compounds (I) and (II) found by us are of general importance for the basic smoky flavour of cigarette smoke