3 -Furanone from methylated sugars

Furanones and pyranones constitute a family of compounds that derive from a common a-dicarbonyl intermediate, namely, CHj-CO-CO-(CHOHJn-CHjR (where R-H or OH). Acetylformoin, which has a fruity-caramel aroma, has been isolated from browned instant orange juice (43) and from a sugar model system containing a catalyst (38). It can be formed by dehydration and cyclization of methyl dihydroxy-ethyl reductone (enediol of the methyl dicarbonyl intermediate), but it decomposes easily in air to pungent compounds (44). 

Hiebl, J. Ledl, F. Severin, T. Isolation of 4-hydroxy-2-(hydroxymethyl) - 5-methyl-3(2H)- furanone from sugar amino acid reaction mixtures. J. Agric. Food Chem. 1987, 35, 990-993. 

Studies have also been made of 3-deoxy-2,5,6-tri-0-methyl-D-en/thro-hex-2-enofuranose (42, R = H, R = Me), prepared from 2,3,5,6-tetra-O-methyl-D-glucofuranose.80 The derived methyl glycosides were separated, and were found to be very acid-labile, affording black polymers under several conditions, but, on reaction with methanol, they gave the methyl 3-deoxy-5,6-di-0-methyl-D-glycero-hex-3-eno-sidulose dimethyl acetals which, like the unsaturated free sugar, gave 5-(D-g/ycero-l,2-dimethoxyethyl)-3(2H)furanone (44) on hydrolysis. 

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