Tetrahydro-4,5-dimethyl-2-furanone,

Updated Entry replacing D-03708 fi-Methyl-y-valerolactone. P,y-Dimethylbutyrolactone. Tetrahydro-4,5-dimethyl-2-furanone [6971-63-7]... 

Wamhoff and Huang obtained alkyl 2,3,4,9-tetrahydro-6-oxo-67/-pyrido[l,2-a]pyrimidine-9-carboxylates 237 in the reaction of 3-(hexahy-dropyrimidin-2-ylidene)-2(3.//)-furanones 235 (R3 = H) and methyl propi-olate in a refluxing alcohol in excellent yields (Scheme 17) (84CB1856). When the reactions were carried out in benzene or dioxane, addition products 236 could be isolated, which then were transformed in quantitative yields to tetrahydro-6-oxo-6//-pyrido[ 1,2-a ]pyrimidine-9-carboxyl-ates 237 by stirring in an alcohol at ambient or elevated temperature. When 3-(hexahydropyrimidin-2-ylidene)-2(3//)-furanones 235 (R3 = Me) were reacted with methyl acrylate or with dimethyl acetylenedicarboxy-late, hexahydro- and tetrahydropyridopyrimidin-6-ones 238 and 239, respectively, were obtained in good yields (84CB1926). 

Recently, AEDA and SHA-0 yielded 41 and 45 odor active compounds for Scheurebe and Gewurztraminer wines, respectively (P). Ethyl 2-methylbutyrate, ethyl isobutyrate, 2-phenylethanol, 3-methylbutanol, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, 3-ethylphenol and one unknown compound, named wine lactone, showed high flavor dilution (FD)- factors (Table I) in Gewurztraminer and Scheurebe wines. 4-Mercapto-4-methylpentan-2-one belongs to the most potent odorants only in the variety Scheurebe whereas cis-rose oxide was perceived only in Gewurztraminer (Table I). 4-Mercapto-4-methylpentan-2-one was identified for the first time in Sauvignon blanc wines (JO). The unknown compound with coconut, woody and sweet odor quality, which has not yet been detected in wine or a food, was identified as 3a,4,5,7a-tetrahydro-3,6-dimethylbenzofuran-2(3H)-one (wine lactone) (JJ). 

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